I've done a talk for the last maybe five
years called VST what the and it
was focusing on extraction and
refractometers and recently we've
started focusing away from just talking
about refractometers because I think for
a while they were a tool that was new
and interesting but and they helped us
learn some things and we were focusing
on the tool but now I think it's time
for us to just focus on the coffee and
what's going on and the refractometer is
kind of like a secondary thing that
allows us to measure some stuff so
tonight is mainly I hope that you'll
walk away from tonight
understanding how extraction works and
what our biggest struggles are to
extract coffee really really well and
that might sound really simple and
lacking context but I hope that by the
end tonight you'll understand what I'm
talking about I hope to dispel some
myths I hope to answer some difficult
questions please if at any time you do
have a question I encourage and prefer
questions during the talk when everyone
is in the same frame of mind and
everyone's dialed in to a certain
concept if you don't understand it I'll
have four other ways to describe it to
you and different analogies rather than
at the end and then we have to sort of
reframe and get back and waste some time
and get back into it so don't feel like
an idiot if you ask a question I didn't
understand any of this at one point
either so I'm more than happy to bring
you up to speed to where I am now so
please put your hand up or yell or
whatever and I'll happily stop at any
point and answer questions so let's
begin first up is strength of coffee
which we call TDS or total dissolved
solids or it's the ratio of water to
dissolve coffee and this is real simple
stuff this is the most basic of starting
to analyze and objectively
appreciate coffee whenever I talk about
strength today I'm not talking about
intensity intensity is this coffee is
intensely bad tasting or
what this coffee has an intense rubber
flavor that rubber flavor can be intense
but the coffee can be strong all week so
whenever I talk about weak or strong
coffee and strength I'm talking about
the TDS of that coffee and whenever I
say specifically intensity or flavor
that's what I'm talking about something
else other than TDS just to clear that
one up so when we're talking about
strength for a filter coffee it's
probably going to be something like
ninety eight point six percent water and
1.4 percent coffee so coffee is an
exceptionally strong flavoring agent
compared to most other things that we
cook with just a tiny little amount of
it will flavor an entire mug of coffee
and that's pretty cool so for espresso
it's even stronger at ten percent and
it's actually really rare that anything
in a chemistry lab or even nature
approaches a ten percent concentration
when you extract it into water it's
quite a rare thing to have a solution
with ten percent total dissolved solids
so an espresso is kind of a rarity and
it's also one of the strongest things we
taste in terms of the number of
chemicals and what an assault on our
mouth it is but in terms of manipulating
strength and moving with strength it's
so simple and easy there's just a single
axis that we can move up or down more
strong less strong so when coffee is not
strong enough I would describe it as
weak watery insipid thin empty and when
it's on the less bad side of not strong
enough delicate or tea like our also in
there as well so that's pretty easy when
it's on the strong side heavy
overwhelming and rough at the usual
flavors we would use and then intense
obviously I just said that I wasn't
talking about intensity with strength
but when you have a strength that's
intense that's intense so that
that doesn't count and then bitter also
has an Asterix because there are
multiple kinds of strengths in coffee
and one of them is when the strength is
too high and there's a certain threshold
and all of you have it and every single
one of you have a different threshold
where once the coffee exceeds a certain
TDS your tongue will just send the
message to your brain or your brain will
interpret the message somewhere along
that chain somewhere your brain says no
that's too strong
and then you just taste it as bitterness
and the easiest way to ascertain whether
it is indeed bitterness from strength
rather than bitterness from some
compound is to just dilute that coffee
with some water and taste it again and
if the bitterness is still there then
you know that it's not strength so there
are lots of different kinds of
bitterness --is in coffee and
unfortunately from a natural selection
point of view apparently bitterness
emerged as don't eat that it's poison
and because we don't die we slowly
develop an appreciation for bitterness
and its various complexities but bitter
itself is still just a signal it's a
binary yes/no maybe it has some
intensity in the in the information as
well so every time we perceive
bitterness sometimes we get clues from
other flavors about what that bitterness
is like if you have Campari you're like
mmm different herbs and bitterness
that's Campari
but with coffee there's so much going on
that sometimes you don't quite know
what's what the bitterness is so
diluting your coffee can be an easy
little trick to check if it's a strength
bitterness problem now when its strength
is correct I kind of like to refer to it
as oh yeah there was a hand hello yeah
like I hated my first Campari
or my first in a brownie I thought it
was disgusting and then the next hot day
I was like wouldn't mind some of that
memory I had the other day and it's like
a a slow appreciation for it and you
might find that those people haven't had
much other bitter foods as well whereas
cocktail people seem to merge quite
nicely into coffee because they've
already started appreciating all of
those bitter interesting combinations of
flavors and chefs as well so yeah I
think it's
only a learned thing because natural
selection tells us that's poison get it
out of your mouth please I like to think
of correct strength as like the music in
a venue if you don't realize that the
music's wrong it's probably good so when
the strength of a coffee is correct it's
usually pleasing mouth filling luscious
rich nuanced creamy it's just good and
you don't need to think about it it just
is and I think that's a really important
thing so in that sense strength is easy
and that's all I'm going to talk about
strength tonight if you want to make it
stronger you use more coffee if you want
to make it weaker you add some water
strength is so simple it is a
one-dimensional line going up and down
for the rest of tonight we're going to
talk about extraction which is far more
interesting and has far more dimensions
and complexities so when I talk about
extraction I'm talking about your
percentage extraction yield or your
yield or how much of your dry dose has
been dissolved in water and taken into
the brewery that's what extraction is or
how much flavor you've taken from the
coffee is the opposite way to think
about it
so extraction also has a nice simple
one-dimensional flavor relationship and
we're going to start off with that but
then we're gonna start adding more
dimensions to it as we go through so
when an extraction is low when we
haven't extracted much you might think
of the last time you pulled a very short
espresso so not much water went through
the espresso and for some reason you
tasted it and it was probably sour
it was probably vegetal salty nutty two
other words that I like to use for
coffees that aren't extremely under
extracted but you're still searching for
what's wrong with it is underwhelming
he's kind of like yo this coffee it's a
bit boring there's not much going on
it's probably under extracted or could
be more is what a lot of people say when
their coffee is under extracted they're
like I just feel like there's more in
this thing it's usually under extracted
now when extraction is too high which
isn't necessarily from the same it's not
like a linear relationship you change
some knobs on your grinder or whatever
and you go from low to high
it's a lot there's a lot of things going
on but when you do somehow over extract
coffee maybe you boiled it in a sauce
pin then it starts to go dry it starts
to go astringent powdery empty and I
mean powdery is in the texture like as
if you've had a drink with cacao in it
like powdered cocoa and once again
bitter with an asterisk because over
extraction can sometimes be bitter as
well so bitterness again is a tricky one
now when extraction is right and this is
the key is it's transparent now the best
analogy I've heard for this is from
George Howell of George Howell coffee in
the US and he says that each step in the
coffee chain is like a window and that
window can be clean or dirty and when
you have bad processing you have a dirty
window that looks back at the farm and
your still when you go when you move
further down the chain you're still
looking through that dirty window to the
farm so if you can clean every window
then your coffee becomes quite
transparent and you can taste what's
going on with it and I would say that
that is a very noble goal for specialty
coffee which I assume all of you are in
because as specialty coffee
professionals we need to justify
charging more for our coffee than other
coffees and if it's not special and
transparent and unique then we're not
really doing anything and it's probably
just I don't know our interior design or
our marketing so balanced nuanced tasty
aromatic parts the clouds is another
phrase that people use a lot but I would
have to say the most important
descriptor for a correct extraction is
sweet every time I've ever chased
sweetness any any time we've ever
ruthlessly tried to get more sweetness
out of a coffee is when it's when our
extraction has increased and improved
and become more even the coffee has
become more sweet and I don't think I've
ever heard anyone ever say that espresso
was too sweet
has anyone ever said that I think I said
it once for a filter coffee so yeah we
have plenty of room to go with more
sweetness you can always find some more
sweetness and no one's going to complain
so always be focusing on that sweetness
so there's another dimension to
extraction which is where we start
getting a little bit more complex
that's slide just slid in there how do
you measure extraction how much have we
taken from the coffee equals how much
coffees and the cup divided by how much
coffee we used simple we don't need to
go any further into that though so this
extra dimension is why extraction is
hard because there's more than one
extraction going on in a cup of coffee
so you could also say that extraction is
uneven it's always uneven because every
single coffee grind that's in every
single one of your brews has a different
diameter a different shape it reacts
with water differently water travels
through paths into and out of it
differently which means that our
extraction isn't perfectly homogeneous
like that last slide would lead you to
believe it's always a mélange a blend of
all of those things so when we have an
uneven extraction we have our classic
under extracted flavors we have our
classic over extracted flavors and
what's left in the middle at the same
time is muddled unfocused some people
would say it's complex some people
actually aim for this flavor because
it's really easy to hit so then you're
very satisfied all the time it's so true
though and aromatic because it smells
and tastes like coffee now this is every
is probably every espresso you've ever
had probably and it's what a lot of
people say is the espresso flavor is
actually just a big old mix of generic
under extraction generic over extraction
muddling up a little bit of correct
extraction and it's why a lot of people
struggle to discern different coffees in
an espresso machine they're like they
just all taste like espresso and some of
you might have been a little bit
embarrassed when you were tasting
espressos and
sort of thinking these all tastes the
same they taste like espresso and that's
ok because they probably did and it's
not your fault so this is normal but
once again we're specialty coffee we're
trying to be special and unique if
everything's generic I can make the best
geisha in the world taste unevenly
extracted and I can make the cheapest
robusta taste unevenly extracted and
they're both going to taste the same
because those generic flavors can be in
any coffee and if that's not the
antithesis of specialty than I don't
know what is but luckily we can improve
this situation we can improve our
extraction and make it more even now the
beauty of making your extraction more
even is that you actually get a two-fold
benefit for every one unit of
improvement you put into improving the
evenness of your extraction you get a
two-fold improvement in the flavor of
that coffee because not only do you
remove the generic bad flavor maybe it's
over extraction or under extraction but
the coffee that was contributing that
over or under extraction is now
contributing a net positive benefit to
the good extraction so it's a - one of
the bad flavor or it's adding one point
because you got rid of a bad flavor and
adding another point because you're
adding good flavor so there's not often
in coffee where one unit of effort gives
you two units of net gain usually it's
marginal gains and we're squeezing to
get anything out of it so if there's one
area where you can put in 20% of effort
and get 80% of results it's in making
your extractions more even so once you
move to a more even extraction you start
to taste your coffee in high definition
I like to use the analogy of going from
a VHS and it's the same movie but now
you're watching it in HD it's the same
storyline everything's the same is the
same studio but now you get to see
everything in crystal-clear clarity now
that may mean that you're tasting the
problems with your roasting or tasting
the problems with the coffee from and
where it's from but roast better and buy
better coffee that's your problem it's
going to be sweeter it's going to be
more
intense and and mouth-filling so you've
actually turned up the volume on the
good flavor now so before where it was
generic coffee now you have really
intense unique coffee which is hopefully
what we're all trying to sell complex
rich aromatic no distractions is a
really important one because there's
none of those generic flavors there's
just the coffee so you've really cleaned
up that window and now you're serving
the coffee that you said you were
serving and your customers are more
likely to appreciate and understand that
ah there was some effort put into this
it actually does taste different so even
extractions are pretty key but
unfortunately every single step in the
supply chain all the way up to brewing
the coffee introduces unevenness and we
have to control all of them lest we
produce an uneven cup so I'm just going
to go through every single way that a
coffee can be uneven just to show you
the gargantuan battle that you have if
you truly want to eliminate all
unevenness in a coffee so step one is
location so if you have a regional
coffee whenever you have a coffee that's
from Colombia called Kalka or a coffee
called Pit Alito or something like that
that is a region that's potentially
hundreds of farms all of them at
different altitudes all of them with
different drying they've got their own
little second arrow at the back where
they dry they coffee a different way
different moisture percentages different
soils different sunlight different
rainfall different moisture everything
and then when you start to slowly move
down that line to micro Lots you get
less and less and less uneven now this
isn't necessarily saying that micro Lots
are better but they generally taste more
unique and that's not micro Lots don't
taste more unique necessarily because
they're better or because anyone put
more effort into them it's because
they're probably going to be more
transparent because there's less
distracting flavors there's more
uniqueness concentrated in a micro light
and less randomness in each cup and
that's probably why micro lots are
usually more interesting now estates or
and plots are in the middle there as
well so you can you can divvy up your a
lot of coffee to be quite macro it could
even be like an entire state of a
country like in an Ethiopian coffee
exchange kind of world all the way down
to micro Lots if you're lucky that
melange of flavour might be what your
customers like so you might have a blend
of coffee that's a milk coffee and to
keep it consistent all year you
deliberately choose a regional lot so
that it's more consistent
whereas micro lots will be quite varied
all the time it really depends but it
does introduce unevenness then of course
there's different farms altitude soils
sunlight plant ages pruning watering
different fertilization regimes all that
kind of stuff all of it introduces
unevenness the variety that's probably
the biggest in terms of what is the
coffee going to do how's it going to
react to the roaster what's going to
happen later because that's at the DNA
level of the plant it's not just - ah
it's how is the cellulose in this being
structured which is going to have a
massive effect so if you're aiming for a
really intensely unique cup of coffee
from Kenya you don't buy coffee
that's SL 2834 and Rui route 11 you
would say no I don't want all those
different varieties from the farm I want
SL 28 please thank you and then it's
probably going to be more unique and
interesting it might be more expensive
but that's the price you pay in terms of
processing obviously picking is huge
sorting is huge how long has it
fermented for and how what percentage is
it dried to drying has a massive effect
on meillard reactions in a roaster if
some of your coffee is wetter and some
of your coffee is drier some of it will
steam and some of it will cook and
that's gonna have a massive effect down
the line on your extraction so this is
all again unevenness unevenness
packaging usually that's okay because
it's all in the same if you buy a
container of coffee it's all packaged in
the same way but if it's shipped for a
long time and one end of the container
was in the Sun on the side of the boat
that's going to get cooked and then the
moisture is going to change the water
activity is going to change and then
even this is going to occur and then age
of course as well so there's a lot
against the green buyer to get evenness
in their coffee but these challenges
have been somewhat surmounted by good
practices and good buyers good farms who
understand what's going on but next we
have roasting so roaster design is
generally pretty terrible for cooking
coffee we're currently specialty coffees
currently using tumble dryers disguised
as coffee roasters and it's really just
like a massive beans at a 30 at a 20
degree angle sitting in a tub getting
spun around by some arms in a barrel
with some hot air coming over the top it
is not even if you showed that to a
process engineer or a chemical plant
engineer who designed you know mass
transfer or anything involving fluid bed
design they would laugh at you
because it's just so uneven the
application of heat to coffee beans is
horrific in drum coffee roasters so yeah
that's against us I honestly don't know
whose fault it is that specialty coffee
industry uses drum Roasters but whoever
it is deserves a lot of pain whoever
bought the first probe at or like I
don't know if Instagram was around then
but whoever did whoever did that yeah
they deserve some pain so we have
development and solubility if your
roaster is accelerating towards the end
of the roast if you have a lot of heat
being applied near the end of the roast
the outside of the bean will be more
cooked than the inside of the bean kind
of like a steak you don't want a charred
rare coffee bean that's delicious when
you have a steak but you really just
want like a awful boiled Suvi steak that
hasn't been seared that is optimal for
coffee and it's really hard to make that
happen in Drumm coffee roasters and then
obviously of course blending yes yes
absolutely if I I would you know the AG
tron color scoring thing the machine
that was actually designed for french
fries for McDonald
and it is a French fry machine and it
uses some specific wavelength of light
or near-infrared to measure the
development of certain chemicals in
coffee and normally Roasters will
measure the outside of their coffee
beans they'll put the beans in a tray
and slide it in the machine it measures
them then they'll grind the beans and
put them back in and now measure the
difference from internal to external
color and a lot of specialty Roasters
pride themselves on having a big
difference between those two numbers and
it's just underdeveloped and savory and
awful those those numbers should be
theoretical identical otherwise you're
just inviting unevenness and if you have
an even roast then you can choose to
move it darker or later but if you have
an uneven roast your freedom of movement
of where you could have moved an even
roast darker or later your freedom is
now there now whenever you make small
adjustments you're gonna be very
frustrated so you want the inside and
the outside to be identical which is
hard but if you can get there then you
have so much more freedom and you're
making coffee that tastes so much more
delicious it's really hard with the drum
Roasters Jeremy challenger from prufrock
who I just hired has a wonderful analogy
for roasting he says roasting and drum
roaster is like throwing a porcelain
vars onto a shelf on the top of the
bookshelf and it has to land on the top
of the bookshelf without breaking the
first time and you don't get any
practice rounds and it's kind of right
because it's so difficult to cook a
little coffee being the right way and
then people blend and they'll
deliberately Brett blend a Brazil and a
kenyan because they're like I want a
chocolaty coffee that's also fruity but
one of them super dense and one of them
is super not dense and they'll roast
them pretty similarly and then you'll
have massive unevenness once again
reducing your freedom to move around and
your Brazil will be over extract your
Kenyan will be under extracted and your
actual you know average extraction is
somewhere in the middle and it's just
not going to be great so roasting adds
another bunch of fun things to evenness
I can't wait for specialty people to use
more fluid bed roasting yes
that's even worse I didn't even bring
that up yeah if you yeah no absolutely
because it's cheaper in it and easier to
just like pre blend yeah yeah that's
true actually if you yeah if you pre
blend you're green that's just adding
even more problems because if you if you
were really good at blending you would
match the solubility and porosity of
your different blend components by
roasting them differently perhaps two
different times or temperatures and then
they would match each other once you
started brewing them and if you actually
focus on that you the blends you start
to make taste so good but the amount of
effort it requires to consistently match
porosity and density of different
coffees in a tumble dryer is like way
too much effort
so nobody does it let me just kind of
like hope that we're close yeah I'm
gonna I'm gonna get to that later yeah
because that's that's a new thing that
we've started figuring out properly so
then finally his grinders and grinders
is we're going to sit for a while
because that's probably what most of you
have control over and what you can
understand and what you can manipulate
most of the time I'm sure there's a few
Roasters here but everyone here I'm sure
uses grinders and has it at least a
little bit of an understanding so
extraction is an average and that's why
it's really hard to understand it is not
just a number that comes out of a
refractometer and that's also why most
most of the criticism I hear about
refractometers
is that it is just an average therefore
it'll never tell you what's actually
going on but an average will at least
give you an idea of more or less and
that's really important so when you have
a lot of different grinds coming out of
a grinder you have small ones bigger
ones way bigger ones on a 2 or 3 orders
of magnitude in terms of microns the
smallest ones have so little mass and so
much surface area so their surface area
to mass ratio is so out of whack that as
soon as water touches it it's fully
extracted
there's almost nothing left to extract
whereas when you have a very large
coffee grind that really taught us
tortuous matrix of cellulose is hard for
the water to get into it's not just
gonna freely dive in and then come back
out again and if you want an example of
that through some coffee beans in hot
water and see if you get a pour oh it's
not going to happen because the water
doesn't get into those coffee beans so
our extraction is going to be made up of
completely extracted tiny grains less
extracted slightly larger grinds and
very very under extracted large grinds
and as you'll find out soon because of
the way spheres work this completely
blows out of proportion once we start
grinding with regular coffee grinders
and it's a real hassle to actually get
full extraction out of our coffee grinds
because of this problem so this was
actually the little card that I printed
out for the judges at the 2013 world
Barista Championship when I used an ek
43 for making espressos I was like I
don't think espresso grinders are
probably optimal for extraction
because of this and its really obvious
you've got a whole bunch of pebbles
coming out of an espresso grinder and a
whole bunch of dust and with a filter
grinder you have a whole lot of really
small coffee grinds and the first time I
ever made an espresso with an ek 43 I
hit 22% extraction whereas I'd been
struggling to hit 18% with a roba and I
didn't do anything weird we didn't
change the grind we didn't change the
machine we just presented the water with
so much more surface area and so much
less big grinds that our extraction
yield went up and the coffee tasted so
much better so this is a really basic
example you know a really big
contrasting example of why it's better
but we're gonna dig in a little bit
deeper and start to really understand
what is better where does it become
better and why and how does that change
occur with
different grinders so this is a classic
particle yes no that would cost a lot of
money but you can choose equipment and
brewing practices that reduce the need
to do that kind of stuff and I'll
definitely get into that later so this
is a classic particle size graph that
would come out of a device called a
laser diffraction particle size analyzer
so what it does is you grind some coffee
grinds chuck them in this machine
it sucks on the through with a vacuum
shoots lasers at them and because of the
magic of physics it measures the
diameter of every single particle which
is pretty neat because I wouldn't want
to do it by hand so it pumps out a graph
like this now on the at the join of the
axes would be zero microns on the x axis
all the way up to that's probably a
millimeter and this is a logarithmic
graph so if that's zero and that's a
thousand then that would be 10 and that
would be 100 microns so it's a scale of
10 a log scale so in this particular
example on the y axis is percentage or
percentage volume and you can pretty
much just say there's more or less of
them like that's the easiest way to
think about that y axis so we have in
terms of volume not in terms of count
this is just how much space do they all
take up cumulatively
we have very little 0 to 100 micron or 0
to 10 micron grades we have some up to
100 we have lots of volume between 100
and 1000 and that's pretty classic for
most grinders and that's a problem so if
we put in this other line here here
you'll see that it's very different in
terms of the 10 to 100 micron range
and it's missing a whole heap of the
probably 400 to 1000 micron grains at
big empty space up the right-hand side
there now for the longest time everyone
in the coffee industry would say the
black line is superior because it has a
taller peak and everyone was very
focused on the peak the peak the peak
the peak and it turns out that the
height of the peak of whatever your
chosen grind setting is isn't really
important what's really important is
what's your total standard deviation of
every little extraction that's happening
from all of these grinds so how big is
the distance from your most extracted
grind to your least extracted grind and
can we manipulate that so with this red
line we've reduced that standard
deviation now this is really important
the reason we want to move this line to
the left instead of eliminating all of
this and moving everything to the right
and making more coffee up in here is
because these little grinds down here
act and brew exactly the same way as the
exterior of all of these so a big grind
doesn't all extract at 13% it extracts
at an average of 13% because the outside
is at 28 and the inside is at zero and
halfway between zero and 28 is 14 so
that was a bad example but 13 14 14
percent that's why your big grind is at
13 percent extraction it's not because
big grinds extract at 13 percent it's
because water only penetrates a little
bit into the big grind leaves the rest
alone destroys the outside and then
leaves and then your average is 13 or 14
so if these guys all down here are
behaving exactly the same as the outside
of these grinds then really we should be
optimizing everything to meet your
maximum so maximum is actually great
because you were already extracting all
of your grinds to maximum it's just that
your average of what you were missing
the inside of those grinds was dragging
your average down
now I'm gonna re explain that in about
five different ways over the next 15
minutes to make sure that you all
completely understand what I'm talking
about now the most optimal grind would
be like that and that's what you would
see from something called a roller mill
that they use to grind for like a
Nespresso capsules and high-volume
industrial grinding and that's an
extremely even very fine grind size
where everything is extracted to 26% and
it tastes amazing but unfortunately
they're really expensive and they're
hard to fit into a room like this so
it's not exactly an ek 43 so we just
have to try and get there we just need
to try and optimize our grind and use
brewing methods that move us down that
way so that we can approach that optimum
so I'm gonna explain it another way
instead of looking at a graph we're now
going to pretend that coffee grounds are
two-dimensional they're flat and the
waters on the outside and the coffee
grown is just like a circle so if we
look at a course a medium and a fine
grind in terms of we've sliced them and
we're looking at them as a cross-section
and we use black white to black as our
extraction zero being white black being
28 or maximum extraction you'll see a
tiny grind is completely extracted
twenty-eight percent probably 25 percent
but 20 28 percent is our theoretical
maximum and the really fine grind only
has a tiny little speck in the middle
that hasn't been extracted a lot the
rest of it is completely extracted now
you notice that that thickness is the
same in the medium grind but because the
medium grain is larger there's more of a
space in the middle that has been less
extracted so therefore the average
extraction for your medium grind is less
but the outside still has the same level
of extraction as
this fine ground and then as we go
course you'll see that thickness is
still the same but the inside is so
large there's such a large proportion of
that ground that hasn't really been
extracted that the average is taken down
again now cast your eyes to the colored
band this is what everyone thinks
extraction is in terms of good and bad
on the same axes so because of this
average phenomenon where our extraction
number is just a mixture of everything
what it leads us to believe is that zero
to 18% is under extracted eighteen to
twenty three percent is great and then
above twenty three percent to twenty
eight percent is over extracted and
that's an illusion because of that
average effect what really happens on
what I strongly believe is the case is
that it's more like this if you actually
measured every grind to see how it was
extracted and you could isolate it
correctly everything up until eighteen
percent would be under extracted
eighteen to twenty three percent would
still be under extracted and then 23
percent to 28 percent would be correctly
extracted because remember the outside
of our grounds are all being completely
fully extracted every delicious coffee
you've ever had the majority of the
flavor you're tasting is actually at 28
percent extraction or whatever is
maximum for that coffee because the
external area of all of the grinds in
that brew that you thought was delicious
were at maximum they were completely
extracted and any number that if you
measured that coffee in at read twenty
two percent what you're really saying is
I really enjoyed this coffee because
some of it was extracted to 28 percent
but there was some that the water missed
so the average extraction is probably 22
so full extraction is actually optimal
yes there is over extraction and that's
why I stumbled on the over extraction
column of the previous slide because
over extraction does occur but you
really have to try and I'm finding more
and more
or that the flavors that we associate
with over extraction you really have to
try to get them and normally it's all
this coffees bitter and dry
must be ever extracted you're roasting
sucks is usually what you know that
reason is or usually what that symptom
is for and you know dryness emptiness
you really have to sit well roasted
coffee in a boiling saucepan for two
minutes to achieve over extracted
flavors or you have to run an espresso
four minutes but if you roast coffee
perfectly and push water through an
espresso machine push a filter coffee
ratio one to sixteen through well
roasted coffee grinds in an espresso
machine it's still not over extracted so
over extraction probably doesn't really
matter that much it's probably your bad
roasting or bad coffee quality or you
were making a brick coffee and left it
in the sand for too long but I think
it's very rare that anyone has actually
tasted truly over extracted coffee maybe
little bits have been ever extracted if
you channeled an espresso and then all
of the hot water was just going through
a tiny little bit that channel has
probably been well over extracted but if
you're evenly extracting I think it's
pretty much almost impossible to
completely over extract the coffee and
this is really counterintuitive and it's
taken me a long time to even like poke
my head up and be like maybe this is
actually what's going on because I
usually get usually get shot down by a
lot of people but this is this is I'm
pretty convinced what's going on and a
lot of people are now becoming convinced
are the same thing yes maybe yeah I
think there's so much pressure from the
water once you actually I'll start
brewing that tamping pressure is a
little bit of relevant because there's
like 100 and what is it hundred and
sixty no 115ps i-49 bar it's like if you
could tamper 115
so I'd be like guns gun show the
pressure from the water I think
completely nullifies any light tamping
that you were doing and just brings it
to max so yeah I'm not sure so I did a
little experiment because I was like
maybe I'm wrong
so that's science the hell out of this
so what we did was we used a sifter and
we sifted we ground some coffee and we
made three fractions of grind sizes they
were 0 to 250 microns or what I would
consider to be very fine particles any
finer than that and we would have been
sifting all day then we had 250 to 500
microns and then 500 microns plus now a
micron is one one thousandth of a
millimeter so 500 microns is half a
millimeter so this is pretty small so
what we did was we measured out the same
weight of each of those different size
ranges put them in cupping bolts and
then poured boiling water on them the
exact same amount of boiling water on
each of these little cupping balls
stirred them vigorously and then in
different cupping balls so it didn't
take samples from the same bowl we did a
specific Bowl for each time we took a
sample of the liquid and then measured
the TDS so this is a pretty good way of
understanding how water penetrates a
grind and what it does and when it
actually starts to come back out again
and give you flavor so at 15 seconds
which was my first Waypoint the five
larger than 500 micron grinds were at 14
percent extraction the 250 to 500 s were
at just under 20 and the 0 to 250 were
at just under 23 and then we measured
again at 30 seconds and the largest
grinds had jumped up to 17 the middle
fraction was just above 21 and the
smallest grinds had only increased a
little bit from maybe twenty two point
eight to twenty three point eight so
maybe 1% more now after that the
smallest grinds barely moved again
the largest grinds had also started to
plateau quite heavily so what you would
expect to see with the large grinds is
that line continuing to go up to meet
the smallest grinds because you would
expect that the extract the water would
go in deeper and deeper and get more get
more coffee and then come back out again
and contribute all of those solubles to
the brew but it didn't it just kept on
lagging and I kept on going
oops all the way up to 10 minutes or 600
seconds and as you can see the 250 to
500 microns eventually got there so the
water in that case eventually got in so
at the maximum size 500 microns it had
traveled in 250 microns because that's
the radius from the edge to the center
of those grinds assuming they're
spherical which is the only thing we can
assume and then it traveled all the way
back out again and eventually we got to
this the same level of extraction as the
smallest grinds but it took 10 minutes
that's why cuttings
I think taste so great is because
they're probably more evenly extracted
because we gave it so long to extract
now the largest grinds were still only
at just up just above 19 19 and a half
percent extraction after all of that
time which means the water hadn't even
touched what was happening on the inside
so this isn't super obvious like sorry
this isn't super new like we anyone
could have predicted that the large
grinds would have a lower extraction
yield than the smallest grounds but what
this data showed us was that the outside
of the grinds and that first layer
that's been penetrated by the water
behaves exactly the same no matter what
the diameter of your coffee grinds if
you do some quick math and figure out
what the depth of extraction is because
if we assume the smallest grinds have
been completely extracted and our
maximum is 24 then you can figure out
how based on how big the grind particles
are how do
the waters gone in because if they're
the same density the whole way through
and you've extracted half then you
figure out what half the volume of that
sphere is in terms of a ring around the
outside and then you know how deep the
waters gone and it was really really
eye-opening because at every single
point where we compared the different
fractions of diameters the water had
penetrated 100 microns almost every
single time within plus or minus 10
microns it was it was going in 100
microns doing its thing and not going
any deeper and that's it so if we look
at our grinds again from that previous
example this is really what we're
extracting from every grind is a layer
now again we're assuming they're
spherical and this is a worst case
scenario so it only gets better for this
argument if they're not spherical which
is great we're only extracting a hundred
microns deep in all of those different
coffee grinds and then the rest is
wasted so that means that the optimal
grind setting absolutely optimal would
be 200 microns maximum which is
ridiculous because any broad would clog
instantly so like that's that's beyond
my paygrade yeah we were staring the
hell out of it the whole time yeah
because the cellulose is still there it
does continue to extract and that's why
the largest that's why that blue line
down the bottom continued to increase
because you had erosion occurring and
that's why you see at a certain point in
the espresso extraction your water flow
it sort of goes quicker and it starts
slow gets quicker and then plateaus and
once it sort of hits that plateau of
flow rate that's when you've eroded
everything that you're going to erode
and now it's just water flowing through
cellulose this is probably because
stuff's eroding 30% of those tunnel
walls have been eroded now the tunnel
walls a bit no the tunnels are bigger so
the water can get in more easily so
that's that slow increase that we're
seeing there probably other things
happening as well but it's not the water
just doesn't travel into a maze because
it feels like it yeah yeah yes
I have no idea yeah I think co2 probably
gets in the way of extraction when it's
really fresh because there's all bubbles
and stuff everywhere especially in
espresso because because we would I
think we normally trended when we were
capturing data from all our espressos
every day the older it got the higher
our extraction yields got I think was
the general trend was there it yes big
glorious yeah yes oh my god yes so much
less yeah but I'm not saying a hundred
microns I'm saying 200 because it's a
radius so the water can go in to the
middle and then come back out again and
it's probably more it's probably like
250 yeah and it also really depends on
how you roasted the coffee if you if you
smash it with a really high temperature
the bean will expand more there was a
guy who did rad experiments back in the
80s where he roasted coffee and then
injected it with mercury to see how
porous it wasn't what the internal
volume was like a real mad scientist
and he found all kinds of cool
things about how roast effects the
expansion of the bean so I would hazard
a guess that if you were a roaster if
you started measuring volume and you
were aiming for maximum volume increase
without roasting too dark your porosity
would be increasing because you've got
the same amount of cellulose it's now
bigger so your porosity would increase
now this coffee that we tested was very
like it was roasted by onyx in the US
and they are they're on the lightest end
that I would enjoy and that means that
it's probably going to be a lot less
soluble so this rule is only for this
coffee in this particular way in this
experiment and if you change the
roasting you might find that you've got
a bigger window that you can play with
in terms of that depth that the water
can actually penetrate the grinds yeah
like way more pores yeah and that's
usually the case because a lot of people
try to under X tracked dark roasts
because they're so eat there so soluble
and so red
be extracted and I need to do way more
testing to actually figure out what is
the spread where's the where's the
average where does it go to it's really
early days and I'm sure labs have done
this properly but we're just like you
know four people in an office in
Melbourne yes yeah it was them it was
the coffee we sent out for the
subscription it was a Guatemalan which
means it was probably cateura from finca
in Seoul it was just the tasty coffee we
had on hand in the officer at the time
because we were sending it out but I'm
not saying that everyone has to grind
superfine tomorrow and that's that's the
problem here is that we can't just
change how we're grinding our coffee to
make them more really small because
everything in clogged and it's not going
to work so if we have a look at these
electron microscope images either off an
electron microscope images you can see
these little bars here or a hundred
microns and it kind of gives you an idea
for how deep the water is actually
penetrating into these grinds and you
can see based on the cell structure of
this coffee how the cell structure and
those pores really defines how the water
can get into the coffee because coffee
isn't this beautiful crystalline
substance that's just endlessly
repeating and perfectly dense it's
really gnarly it's got little holes and
tunnels and bits and bobs and coffee
flavor hanging off walls and it's not
optimal for water flow it's possibly the
worst thing for water flow and this is
even more zoomed in that's a hundred
microns again that that white line
that's how deep the water's getting in
that experiment you know it's a couple
of pause maybe it gets into one poor
finds a hole gets into the next one it
stops that's it so it's really tricky
for water to get into this stuff it is
not designed for that so essentially
what I'm saying is over extract
isn't really a thing it exists yes and
it tastes awful yes but you're probably
not going to encounter it what you need
to do is always aim for more extraction
now every time I say this someone goes
but more inspection doesn't always taste
good and that's because what you're
normally doing is you're measuring your
coffee you're grinding to fine tasting
it again seeing that the extraction went
up a little bit and saying that over
extraction is bad and you shouldn't aim
for more that's like one case in this
entire multi-dimensional sphere of how
to make coffee extracted more yes it can
taste worse when you increase your
average extraction but if you understand
how averages work then you need not be
scared about increasing the average if
you do it in the right way so the bad
way to do it is to grind so fine that
you end up going backwards so this I
took this up on the blog years ago as
you continue to grind finer your
extraction will go up obviously of
course it will and then at a certain
point you hit the maximum amount of
extraction that you're going to get with
that brewing device that coffee that
combination variables and as you
continue to grow and finer you're going
to go off a cliff and your extraction is
going to go back down again so you need
to find that little maximum that local
maximum it's not a local maximum it's
the maximum extraction that you can get
from that coffee and that is always
going to be the best tasting coffee in
my opinion maybe you like under
extracted coffee that's cool I think
that's going to be the best tasting
representation of that coffee that you
can possibly serve is that that maximum
point now a lot of people as I said
complain that it doesn't always tastes
better when you increase the extraction
I would argue either that you're
roasting sucks you don't have a pellet
or if you're doing it the wrong way
because it's always better so this is
what's normally happening when people
they have an uneven extraction and they
say Matt you're an idiot extracting more
is just going to make it taste bitter
and awful what they're already doing is
that uneven extraction that I was
talking about before this is one coffee
and as we've learned it's
not a melange of under extraction
spreading evenly through to over
extraction it's under extracted
internals of groins and over extracted
externals so that's represented with the
same colors as before but we have this
line here where it's not not tasting
great it's kind of over extracted and
it's not good if they increase the
extraction of this coffee that has to
move even further into the depths of
over extraction before the bulk of their
coffee or it may be half of their coffee
even begins to become well extracted so
of course you would argue that
increasing your extraction is bad when
it's uneven because it's already so
close to over extraction and not tasting
good and also already so under extracted
at the same time that you don't have any
freedom to move and you're kind of stuck
so of course you don't want to increase
it and if you make your extraction quite
even then it's going to be sitting
somewhere in the middle you've combined
both of those you've doubled its size
and it's now sitting in a reasonable
level of extraction but because you've
reduced the amount of space that it
takes up on that extraction axis you'll
now free to move that tiny bubble of
coffee extraction up or down which means
you can bump it all the way up I don't
know what's going with this slide all
the way up to as close to maximum that
you possibly can
and then you're using less coffee you're
extracting more of it it's more sweet
you have less under extracted you have
less over extracted and it's just more
generally delicious
so once you understand that improving
the evenness of your coffee to produce
more extraction is great then you really
open up an entire new realm of
deliciousness and it's far more freeing
than any other variables that you can
adjust so I have practical tips yes I
made a at the mal Koenig Factory in
Hamburg I got to play with their giant
industrial grinder that has burs about
like that big I think it's called like a
DK 27 and it does tons and hour
and we put in a little 20 gram dose in
the top and it was like just just
disappeared we got three yeah we got
three grams out but we dialed it in and
got 26% and it was it was otherworldly
it was bizarre but I've had similar
levels of extraction at in espresso
which is frightening from roller mill
grinding as well
I felt like single-serve pods and things
like that
so in terms of brewed coffee you need to
treat every grind the same way imagine
that you've got a wonderful democratic
republic and every single one or maybe
socialist and every single one of those
grinds needs to be treated exactly the
same way all of them and they need to be
the same size and everything needs to be
fair agitate and stir
you're not gonna over extract a filter
coffee by stirring it at the beginning
that's absolutely ridiculous
you're extracting it for three minutes
stirring it at ten seconds isn't going
to do nothing except make your
extraction more even which is going to
make it more delicious agitation and
stirring is to get every grind wet asap
so just get everything wet if you see
bubbles later then something was dry and
has just become saturated and released
co2 that's a really great indicator in a
pour-over or a cupping bowl or whatever
that not all of the grinds were wet
don't grind so find that flow is choked
because there is that maximum and that
decline again you need to find the max
that's as fine as you can go and if you
do want to sift he's gone the sifting
that is gone there is if you want to
sift I would recommend sifting
everything larger than 500 microns
because that's the fastest sifting you
can do because I will just pass straight
through and then the boulders are left
behind there's no tapping and shaking
and all that kind of stuff
everything just drops through a 500
micron sieve except the worst offending
boulders and you then you can regrind
those if you're grinders appropriate for
that and you'll improve your coffee to
no end instantly in terms of drip I
didn't have time to redo this but I
recommend flatbed Brewers more than the
cone sort of shape because there's no
reason the water
wants to travel all the way down to the
bottom of a cone that seems a little bit
prosperous but flatbed at least if the
water is flowing through one part of the
coffee it has the same level of
incentive to flow through every part of
the coffee just seems to make more
simple sense
so W dose and stirrup that's easy
make sure the grinds are up on the edges
make sure the water levels never too
high because then it just wants to go
through the paper if you can get if you
were water and you have the choice of
going through coffee or paper you've got
you
you go through paper which so don't pour
too high
keep your agitation and level the same
like I see a lot of Brewster's whipping
their little kettles which is very
inconsistent just keep it a consistent
height and let gravity do the pin drop
for you in terms of batch brew if you
need to turn off the sensor if you have
a new fedko so that it doesn't turn off
when you take the basket out there is
options for that or trick it by like
cutting out the magnet and gluing it to
it there's ways and make sure that the
number of pulses keeps the coffee wet
but the bit the water height never too
high like you don't want to have three
pulses that completely over blow the
basket and then take forever to drain
out you want to just be constantly
delivering nice hot water and keeping
that level just sitting above the grinds
there is always a minimum dose in the
batch Brewers where and once you grow
below that minimum dose the water just
goes through the sides and there's no
reason for it to go through the coffee
it's really weird way the water delivery
in batch Brewers this has nothing to do
with the rest of the lecture but nobody
actually weighs what comes out of that
batch brew and there trust what's on the
screen it's wrong so weigh at least five
and then each day way to and an average
it and that's your brew water wait for
the day and then measure it when the
dishwashers on and be depressed because
it'll be less and generally with batch
brews just grind coarser and I know I
didn't say to grind course you have to
grow in finer but the problem with batch
brew is that there's no there's no ins
there's no pressure pushing that water
through finely ground coffee
if the water can go out the side it'll
go out the side so you need to make it
as easy for the water to go through the
coffee as it is
through the paper so that's pretty
coarse in terms of immersion dump the
water in as fast as you can so that the
dumping of the water stirs the grind so
you don't need to carefully you know
drop water in just dump it and then
that'll agitate everything for you
stir it but don't leave it spinning I
find with arrow presses if you leave it
spinning some grounds will be sat still
and others will be whizzing around at
the top and they're going to be more
extracted than the ones that are still
down the bottom marginal gains every one
increase yeah use two papers for an
arrow press it's always better and the
usual inversion is fine
now for espresso I everyone thinks I get
paid by VST but he's so stingy
he doesn't give me a cent VST baskets
way better than everything else just use
them that's so cheap and they last
forever
they don't last forever they last for a
very long time if you have a curved
tamper put it on the Shelf it looks nice
and get a flat tamper because your
extraction will become uneven with a
curved tamper because water doesn't like
going through not flat things evenly
fill your hopper up with espresso
grinders if the bed depth of the coffee
before the birds is different than your
particle size distribution would be
different
that's a mad design error and then
distribution I still have no idea what
the best distribution method is we
released some results for that the other
day some of you might have read it and
we discovered that using the OCD tool
kind of spinny things is better than
doing nothing but it's just as good as
the free method of just like tapping the
portafilter with your palm
which is a little just a little bit
cheaper than 2-hundred what is it a
hundred and twenty quid or whatever it
is over here but we're working on what
is optimal and how do we get there
rather than just that doesn't work let's
do something cheaper yes that's what we
need to do next we need to test ten
Muppets sorry baristas and see and see
if they can actually do it consistently
and then we also need because the other
problem with the testing was that
everyone who sent us a distribution tool
for testing said we're not claiming that
it does anything but here it is for
testing so so if it doesn't work we
didn't say it worked but if it did do
something that'll be great if you could
tell everyone and they also said and
make sure that it's evenly distributed
before you use the tool so to test the
OCD based on what they recommend to use
the OCD with we literally had to do
stock filleth before or whatever that is
before we use the OCD so anyway
it's all very silly what we are working
on is this silly thing which looks like
a murder weapon that kind of like
punctures the coffee and it's not it's
not as much about needles making paths
through the coffee as it is adding so
much volume to the bed of grinds that
the grinds have to move to accommodate
them and they move sideways because
there's no reason that they they can't
move down and they're probably not going
to move up unless they have to so we're
kind of calling it sideways tamping and
honestly I think it's the silliest thing
when you took when you just like move
this thing that sticks holes in the
coffee but on most of our tests so far
our extraction yields increased by two
percent which is the largest increase
I've ever seen since using going to a
good flat burger rinder or moving from a
curve to a flat tamper so I don't care
what it looks like if it does the job
and it increases their espresso
extractions by two percent and wins
every blind tasting that we've done so
far it's doing something so I'll sell it
and it'll make your coffee taste better
if you want to use it but that's we're
still testing it
still trying to figure out exactly what
it does and does it not work in some
cases as well so we're still a little
while away from actually releasing it I
still have no idea if the sideways
tamping thing is even real or not but if
blind taste tests and extraction yields
are consistent across the board we will
start manufacturing something like this
and it's obviously not for high volume
cafes that's an ugly prototype version
that we just busted out in a week it'll
look much better than that but if it
does work will release y-you know we
think it works and people can choose for
themselves yeah it's a weird thing
espresso
app so gameplan from now on after
tonight is more extraction that's pretty
obvious even more extraction than you
just did until it's worse and then take
a little step backwards so always more
always more more more more more more
more more more more until it tastes bad
and then dial it back a little bit and I
promise you that's the best cup of
coffee that you can possibly make so
that seems pretty simple now here's the
silly part of tonight it's all been
value up until now we just released an
online course that is pretty much the
stuff I talked about tonight in detail
and we go into algebra in terms of how
to manipulate all the different aspects
of a coffee brew we go into extraction
theory we have spreadsheets and
calculators and tools and all kinds of
stuff this is what barista hustle is
mainly sort of going to be focusing on
now is online education and I think
there's already 400 students in there
that have finished or already started
the course and we're getting we're
getting very good reviews and we're
continually updating as people ask
questions so it is more like a living
document this first course so that's up
and available get your managers to buy
it for you or we're going to continue to
offer more courses we want to get into
doing a barista or cafe financial
literacy course and try to tailor it to
each major sort of area so that if your
baristas or if your managers or cafe
owner
and your staff have done a course like
this hopefully they can make your
business more profitable and everyone
can make more money we want to do a
advanced espresso course so this is a
what we talked about tonight was kind of
like a meta-level extraction not
necessarily filtered not necessarily
espresso we want to do an espresso a
specific course that goes super deep we
have a lot of research equipment
arriving for so we can actually figure
out what the hell's going on with
espresso we want to do a filter coffee
course all kinds of stuff because it
turned out that releasing things for
free on a blog is cool but releasing
everything for free on a blog it doesn't
pay any salaries and leads to things not
going places because that's how the
internet works these days so we decided
to change tack and go down the very
professional very advanced courses
online and certification route because
education is pretty lacking in the
coffee industry and you don't have to do
it but I think they're pretty good
courses and they're pretty advanced and
relevant compared to a lot of the
incumbents that are out there at the
moment so that's the little silly part
of tonight
now if the questions now I have a rule
about questions at question times it
talks if your first sentence doesn't
finish with a question mark you've
surrendered your question that's the
rule if there was a second sentence then
you also surrendered your question yeah
we're we don't there's the rest of the
people in this room don't want to hear
your story and question time isn't
necessarily about sounding smart because
you asked a smart question it's about
figuring stuff out
so many questions sessions get derailed
because everyone wants to show everyone
how smart they are by answering the
question they already know the answer to
but I'd much prefer to answer questions
that you don't know the answer to
because then everyone learns so I'm yeah
anyone anyone can ask anything if you
like yes
worst water London's up there but I
think Copenhagen takes the takes the
winner for the worst tap water
it's like 1,200 ppm it's like more than
Evian it's a lot of stuff in your water
like that's ocean
oh oh she annek you don't need that much
for dark roasts not even not even maybe
two orders of magnitude less would be
acceptable still yeah we we've got a
bunch of different have you read the
articles that we put up about water
chemistry and just start experimenting
with that we we made a chart with lots
of different points and different
combinations that represent different
standards but also different cities that
have coffee good coffee cultures and you
can start experimenting by with two
concentrates that we designed so that
each gram of concentrate equals one
milligram per liter of the eventual
chemical and if you start playing around
with those with one coffee and making
different different water recipes you
can really start to understand how the
knobs on that extra sketch actually move
flavor and you the only way to do it is
just to do it yes just give it a crack
it you know take get a couple mates buy
some bath salts have a bath party
afterwards or something have a spa and
just just have some fun yeah yes
because calcium making calcium into
solution is really hard unless it's
already it's what is so weird if it's
not already in the water and it's like
slowly dissolved in there over eons and
that's a natural water source
you can't just jam calcium into water
it's really hard and it screws up other
chemistry's as well it's like you do one
thing in water and then ten other things
will change and then you have to like
it's like herding cats every time you
change one variable so the magnesium
most people who have played around with
coffee chemistry and have played with
cat played with magnesium have been like
actually magnesium tastes a lot better
than calcium does so we figured for ease
of use go to the hardware store pick it
up we just go with those chemicals yeah
ease of use what an exploration was the
biggest thing that we wanted to do there
for sure yeah cool anyone else yeah at
the back well they they they do that in
roller mills because a roller mill will
usually have three sets of rollers so
it's double regrinding I would reground
boulders after you sit at them out but
generally I would advise against tree
grinding because the amount of torque
required by the grinder motor to re
grind grounds and get them through would
normally stall the motor and if your
grinder isn't designed correctly that
will damage it or it'll overheat or
something will happen and regrinding
grinds means that there's grinds where
there were beans in the pre grinding
stage and then it gets really messy so
yeah I don't know it's not great just
grind finer yes
yes are you struggling to get it slow
enough is it going really quick and
you're it find the finest sitting your
birds are not aligned so you need to
need to align your burrs at the moment
they're like this and they're sort of
spinning off axis and that means that
you're getting a mix of fine and coarser
grinds if you make them parallel you can
make them on average get a lot closer so
we have a guide for that as well well
now I think a youtube channel or
something on how to align them with
shims and takes about an hour and it
sucks but it's totally worth it because
your coffee will be instantly better and
more even and taste great and you'll
have more freedom in terms of the grind
setting you can use absolutely yeah and
especially if you're at the finest
setting that means something's wrong
you should be at about 2:30 to 3:00
o'clock
wait no three o'clock is maximum no just
after 3 o'clock maximum you should be at
like 2:15 at 2:45 o'clock yeah 1:00 or
2:00 o'clock
sure yeah was there customary yeah once
once it tastes good yeah now because
every every coffee day gas is slightly
differently in how you roast it as well
so whenever it tastes good yeah yeah
there's a lot of masturbation around
roast date optimal roast date time and I
think is could be simplified to when
does it taste good yeah neat yes yeah we
usually run it like whenever we do
anything like stats related or protocol
related we run it past some peers it's
not a form of peer review process and at
the moment we did start looking into
that and I am an author on a paper with
about grind
besides analysis but the I think the
amount of value that I can or that we at
barista hustle can create and the speed
at which we can move in terms of just
dabbling in different things to see
what's going on how can we optimize this
very quickly how can we optimize that we
can probably do ten to a hundred times
more value we or we can create ten to a
hundred times more value for the coffee
industry by being a little bit quick and
reckless honestly compared to very
formal peer-reviewed stuff which is very
slow and yes our you know our P P would
be closer to 0.05 or you know we improve
it if we did heat morsel sample sets but
I think there is a balance of how quick
and reckless we can be this isn't
medicine so we're gonna kill anyone I
hope and I think that we can create a
lot of net utility by doing these
experiments the way we're doing them
asking couple scientists is that do you
think this is ridiculous and they're
like now give it a crack and then
publishing those results are moving on
we can help a lot more people and move
things a lot more quickly and if UC
Davis and SCA want to like formalize
stuff afterwards and you know lock it
all in great but yeah we're I think
we're creating more I'm just trying to
create value like every meeting we have
unlike more value how do we how do we
you know move things forward quickly and
peer-review and like formal stuff like
that because it is so structured and
there is such a process that you have to
slowly go through it just slows things
down and we wouldn't be profitable
anymore we'd have to start getting
funding in other ways and everyone he'll
be bored because I do in the same speech
for three years because that's all we'd
be able to focus on is the one paper for
three years or whatever it was so I wish
that it was easier to do peer-reviewed
you know like published papers that'd be
amazing but expensive yes
yeah yeah I mean acrylamide is a
carcinogen but you know so is everything
and there's background background
radiation in this room right now
that's probably killing us too yeah I
think California is probably the most
nanny state but also they've done some
pretty valuable stuff for citizens in
terms of protecting them like they're
pretty easy Ellis I would say
overzealous maybe but in but sometimes
they really like do a great job oh yeah
what I don't know what temperature is
acrylamide created at 2:30 or something
yeah I don't know I just keep roasting
even further and then it's gone yeah
right yeah I mean there's so many
carcinogens in the world and every week
another paper comes out that is a meta
study of coffee drinkers and each week
it veers towards it's gonna kill you or
it doesn't kill you and there's a lot of
other things that have a much higher
confidence interval of it's probably
going to kill you so I don't know it'll
probably be on BuzzFeed for a year
afterwards and then everyone forget
about it because they're not going to
give up coffee I mean there's so many
other products in the state of
California that have this product is
known to cause birth defects etc etc and
people are still chugging it so yeah I
don't know maybe sales will drop and
much what a turmeric lattes will take
off for a month I don't know yes
you may yield is in more water through
the coffee yeah but then you'll
sacrifice you'll have less strength yeah
and that's always the compromise you
know you've got your seesaw that you
want to balance on and if you're if
you're at the point where you're like I
don't want this to be any weaker and I
am grinding as fine as I can that's when
you start ruthlessly going through every
other possible thing you know how did we
distribute it how's the water going
through it did something else happen
what's the shower screen doing what's
the basket doing how did we you know and
just keep keep going keep chipping away
at how to make this more even and you'll
notice that your extraction and strength
simultaneously go up when you do a good
when you're at that maximum and then you
do a good job with other things like
distribution they'll both move up
together and that's a win yes well the
Arrhenius equation which is like the
basic if you increase temperature you
extract more stuff you know sort of
basic equation is every 10 degrees
Celsius as a rule of thumb will double
your rate of extraction so that's the
easy answer I mean make it as hot as you
can so it still tastes good because you
could pull faster shots and then you're
more efficient so great so if your
coffee starts to taste terrible at 96 no
matter what you do bring it down but if
your coffee still tastes great at 96
then you can pull faster shots and be
more efficient and make more money and
laugh all the way to the bank with your
I don't know five extra dollars a day or
something yeah sweet yes
I want California to put a food warning
on that before they put it on McCulloh
minds because that's like you may as
well just spit on the coffee if you're
gonna blow it yeah yeah it tastes less
like carrot when you do that like chef
tastes pretty bad normally it should
come out from the roasting like if
you've still got a lot of chaff in your
grinds after roasting than you probably
pros to light that's a very rule of
thumb but if you need to be blowing it
off then that's that's a problem I think
well there's not enough movement or
airflow in the roaster or something's
going on yeah what's the time Nick maybe
I think we're getting pretty close to it
we nailed it pretty fun evening nice
years called VST what the and it
was focusing on extraction and
refractometers and recently we've
started focusing away from just talking
about refractometers because I think for
a while they were a tool that was new
and interesting but and they helped us
learn some things and we were focusing
on the tool but now I think it's time
for us to just focus on the coffee and
what's going on and the refractometer is
kind of like a secondary thing that
allows us to measure some stuff so
tonight is mainly I hope that you'll
walk away from tonight
understanding how extraction works and
what our biggest struggles are to
extract coffee really really well and
that might sound really simple and
lacking context but I hope that by the
end tonight you'll understand what I'm
talking about I hope to dispel some
myths I hope to answer some difficult
questions please if at any time you do
have a question I encourage and prefer
questions during the talk when everyone
is in the same frame of mind and
everyone's dialed in to a certain
concept if you don't understand it I'll
have four other ways to describe it to
you and different analogies rather than
at the end and then we have to sort of
reframe and get back and waste some time
and get back into it so don't feel like
an idiot if you ask a question I didn't
understand any of this at one point
either so I'm more than happy to bring
you up to speed to where I am now so
please put your hand up or yell or
whatever and I'll happily stop at any
point and answer questions so let's
begin first up is strength of coffee
which we call TDS or total dissolved
solids or it's the ratio of water to
dissolve coffee and this is real simple
stuff this is the most basic of starting
to analyze and objectively
appreciate coffee whenever I talk about
strength today I'm not talking about
intensity intensity is this coffee is
intensely bad tasting or
what this coffee has an intense rubber
flavor that rubber flavor can be intense
but the coffee can be strong all week so
whenever I talk about weak or strong
coffee and strength I'm talking about
the TDS of that coffee and whenever I
say specifically intensity or flavor
that's what I'm talking about something
else other than TDS just to clear that
one up so when we're talking about
strength for a filter coffee it's
probably going to be something like
ninety eight point six percent water and
1.4 percent coffee so coffee is an
exceptionally strong flavoring agent
compared to most other things that we
cook with just a tiny little amount of
it will flavor an entire mug of coffee
and that's pretty cool so for espresso
it's even stronger at ten percent and
it's actually really rare that anything
in a chemistry lab or even nature
approaches a ten percent concentration
when you extract it into water it's
quite a rare thing to have a solution
with ten percent total dissolved solids
so an espresso is kind of a rarity and
it's also one of the strongest things we
taste in terms of the number of
chemicals and what an assault on our
mouth it is but in terms of manipulating
strength and moving with strength it's
so simple and easy there's just a single
axis that we can move up or down more
strong less strong so when coffee is not
strong enough I would describe it as
weak watery insipid thin empty and when
it's on the less bad side of not strong
enough delicate or tea like our also in
there as well so that's pretty easy when
it's on the strong side heavy
overwhelming and rough at the usual
flavors we would use and then intense
obviously I just said that I wasn't
talking about intensity with strength
but when you have a strength that's
intense that's intense so that
that doesn't count and then bitter also
has an Asterix because there are
multiple kinds of strengths in coffee
and one of them is when the strength is
too high and there's a certain threshold
and all of you have it and every single
one of you have a different threshold
where once the coffee exceeds a certain
TDS your tongue will just send the
message to your brain or your brain will
interpret the message somewhere along
that chain somewhere your brain says no
that's too strong
and then you just taste it as bitterness
and the easiest way to ascertain whether
it is indeed bitterness from strength
rather than bitterness from some
compound is to just dilute that coffee
with some water and taste it again and
if the bitterness is still there then
you know that it's not strength so there
are lots of different kinds of
bitterness --is in coffee and
unfortunately from a natural selection
point of view apparently bitterness
emerged as don't eat that it's poison
and because we don't die we slowly
develop an appreciation for bitterness
and its various complexities but bitter
itself is still just a signal it's a
binary yes/no maybe it has some
intensity in the in the information as
well so every time we perceive
bitterness sometimes we get clues from
other flavors about what that bitterness
is like if you have Campari you're like
mmm different herbs and bitterness
that's Campari
but with coffee there's so much going on
that sometimes you don't quite know
what's what the bitterness is so
diluting your coffee can be an easy
little trick to check if it's a strength
bitterness problem now when its strength
is correct I kind of like to refer to it
as oh yeah there was a hand hello yeah
like I hated my first Campari
or my first in a brownie I thought it
was disgusting and then the next hot day
I was like wouldn't mind some of that
memory I had the other day and it's like
a a slow appreciation for it and you
might find that those people haven't had
much other bitter foods as well whereas
cocktail people seem to merge quite
nicely into coffee because they've
already started appreciating all of
those bitter interesting combinations of
flavors and chefs as well so yeah I
think it's
only a learned thing because natural
selection tells us that's poison get it
out of your mouth please I like to think
of correct strength as like the music in
a venue if you don't realize that the
music's wrong it's probably good so when
the strength of a coffee is correct it's
usually pleasing mouth filling luscious
rich nuanced creamy it's just good and
you don't need to think about it it just
is and I think that's a really important
thing so in that sense strength is easy
and that's all I'm going to talk about
strength tonight if you want to make it
stronger you use more coffee if you want
to make it weaker you add some water
strength is so simple it is a
one-dimensional line going up and down
for the rest of tonight we're going to
talk about extraction which is far more
interesting and has far more dimensions
and complexities so when I talk about
extraction I'm talking about your
percentage extraction yield or your
yield or how much of your dry dose has
been dissolved in water and taken into
the brewery that's what extraction is or
how much flavor you've taken from the
coffee is the opposite way to think
about it
so extraction also has a nice simple
one-dimensional flavor relationship and
we're going to start off with that but
then we're gonna start adding more
dimensions to it as we go through so
when an extraction is low when we
haven't extracted much you might think
of the last time you pulled a very short
espresso so not much water went through
the espresso and for some reason you
tasted it and it was probably sour
it was probably vegetal salty nutty two
other words that I like to use for
coffees that aren't extremely under
extracted but you're still searching for
what's wrong with it is underwhelming
he's kind of like yo this coffee it's a
bit boring there's not much going on
it's probably under extracted or could
be more is what a lot of people say when
their coffee is under extracted they're
like I just feel like there's more in
this thing it's usually under extracted
now when extraction is too high which
isn't necessarily from the same it's not
like a linear relationship you change
some knobs on your grinder or whatever
and you go from low to high
it's a lot there's a lot of things going
on but when you do somehow over extract
coffee maybe you boiled it in a sauce
pin then it starts to go dry it starts
to go astringent powdery empty and I
mean powdery is in the texture like as
if you've had a drink with cacao in it
like powdered cocoa and once again
bitter with an asterisk because over
extraction can sometimes be bitter as
well so bitterness again is a tricky one
now when extraction is right and this is
the key is it's transparent now the best
analogy I've heard for this is from
George Howell of George Howell coffee in
the US and he says that each step in the
coffee chain is like a window and that
window can be clean or dirty and when
you have bad processing you have a dirty
window that looks back at the farm and
your still when you go when you move
further down the chain you're still
looking through that dirty window to the
farm so if you can clean every window
then your coffee becomes quite
transparent and you can taste what's
going on with it and I would say that
that is a very noble goal for specialty
coffee which I assume all of you are in
because as specialty coffee
professionals we need to justify
charging more for our coffee than other
coffees and if it's not special and
transparent and unique then we're not
really doing anything and it's probably
just I don't know our interior design or
our marketing so balanced nuanced tasty
aromatic parts the clouds is another
phrase that people use a lot but I would
have to say the most important
descriptor for a correct extraction is
sweet every time I've ever chased
sweetness any any time we've ever
ruthlessly tried to get more sweetness
out of a coffee is when it's when our
extraction has increased and improved
and become more even the coffee has
become more sweet and I don't think I've
ever heard anyone ever say that espresso
was too sweet
has anyone ever said that I think I said
it once for a filter coffee so yeah we
have plenty of room to go with more
sweetness you can always find some more
sweetness and no one's going to complain
so always be focusing on that sweetness
so there's another dimension to
extraction which is where we start
getting a little bit more complex
that's slide just slid in there how do
you measure extraction how much have we
taken from the coffee equals how much
coffees and the cup divided by how much
coffee we used simple we don't need to
go any further into that though so this
extra dimension is why extraction is
hard because there's more than one
extraction going on in a cup of coffee
so you could also say that extraction is
uneven it's always uneven because every
single coffee grind that's in every
single one of your brews has a different
diameter a different shape it reacts
with water differently water travels
through paths into and out of it
differently which means that our
extraction isn't perfectly homogeneous
like that last slide would lead you to
believe it's always a mélange a blend of
all of those things so when we have an
uneven extraction we have our classic
under extracted flavors we have our
classic over extracted flavors and
what's left in the middle at the same
time is muddled unfocused some people
would say it's complex some people
actually aim for this flavor because
it's really easy to hit so then you're
very satisfied all the time it's so true
though and aromatic because it smells
and tastes like coffee now this is every
is probably every espresso you've ever
had probably and it's what a lot of
people say is the espresso flavor is
actually just a big old mix of generic
under extraction generic over extraction
muddling up a little bit of correct
extraction and it's why a lot of people
struggle to discern different coffees in
an espresso machine they're like they
just all taste like espresso and some of
you might have been a little bit
embarrassed when you were tasting
espressos and
sort of thinking these all tastes the
same they taste like espresso and that's
ok because they probably did and it's
not your fault so this is normal but
once again we're specialty coffee we're
trying to be special and unique if
everything's generic I can make the best
geisha in the world taste unevenly
extracted and I can make the cheapest
robusta taste unevenly extracted and
they're both going to taste the same
because those generic flavors can be in
any coffee and if that's not the
antithesis of specialty than I don't
know what is but luckily we can improve
this situation we can improve our
extraction and make it more even now the
beauty of making your extraction more
even is that you actually get a two-fold
benefit for every one unit of
improvement you put into improving the
evenness of your extraction you get a
two-fold improvement in the flavor of
that coffee because not only do you
remove the generic bad flavor maybe it's
over extraction or under extraction but
the coffee that was contributing that
over or under extraction is now
contributing a net positive benefit to
the good extraction so it's a - one of
the bad flavor or it's adding one point
because you got rid of a bad flavor and
adding another point because you're
adding good flavor so there's not often
in coffee where one unit of effort gives
you two units of net gain usually it's
marginal gains and we're squeezing to
get anything out of it so if there's one
area where you can put in 20% of effort
and get 80% of results it's in making
your extractions more even so once you
move to a more even extraction you start
to taste your coffee in high definition
I like to use the analogy of going from
a VHS and it's the same movie but now
you're watching it in HD it's the same
storyline everything's the same is the
same studio but now you get to see
everything in crystal-clear clarity now
that may mean that you're tasting the
problems with your roasting or tasting
the problems with the coffee from and
where it's from but roast better and buy
better coffee that's your problem it's
going to be sweeter it's going to be
more
intense and and mouth-filling so you've
actually turned up the volume on the
good flavor now so before where it was
generic coffee now you have really
intense unique coffee which is hopefully
what we're all trying to sell complex
rich aromatic no distractions is a
really important one because there's
none of those generic flavors there's
just the coffee so you've really cleaned
up that window and now you're serving
the coffee that you said you were
serving and your customers are more
likely to appreciate and understand that
ah there was some effort put into this
it actually does taste different so even
extractions are pretty key but
unfortunately every single step in the
supply chain all the way up to brewing
the coffee introduces unevenness and we
have to control all of them lest we
produce an uneven cup so I'm just going
to go through every single way that a
coffee can be uneven just to show you
the gargantuan battle that you have if
you truly want to eliminate all
unevenness in a coffee so step one is
location so if you have a regional
coffee whenever you have a coffee that's
from Colombia called Kalka or a coffee
called Pit Alito or something like that
that is a region that's potentially
hundreds of farms all of them at
different altitudes all of them with
different drying they've got their own
little second arrow at the back where
they dry they coffee a different way
different moisture percentages different
soils different sunlight different
rainfall different moisture everything
and then when you start to slowly move
down that line to micro Lots you get
less and less and less uneven now this
isn't necessarily saying that micro Lots
are better but they generally taste more
unique and that's not micro Lots don't
taste more unique necessarily because
they're better or because anyone put
more effort into them it's because
they're probably going to be more
transparent because there's less
distracting flavors there's more
uniqueness concentrated in a micro light
and less randomness in each cup and
that's probably why micro lots are
usually more interesting now estates or
and plots are in the middle there as
well so you can you can divvy up your a
lot of coffee to be quite macro it could
even be like an entire state of a
country like in an Ethiopian coffee
exchange kind of world all the way down
to micro Lots if you're lucky that
melange of flavour might be what your
customers like so you might have a blend
of coffee that's a milk coffee and to
keep it consistent all year you
deliberately choose a regional lot so
that it's more consistent
whereas micro lots will be quite varied
all the time it really depends but it
does introduce unevenness then of course
there's different farms altitude soils
sunlight plant ages pruning watering
different fertilization regimes all that
kind of stuff all of it introduces
unevenness the variety that's probably
the biggest in terms of what is the
coffee going to do how's it going to
react to the roaster what's going to
happen later because that's at the DNA
level of the plant it's not just - ah
it's how is the cellulose in this being
structured which is going to have a
massive effect so if you're aiming for a
really intensely unique cup of coffee
from Kenya you don't buy coffee
that's SL 2834 and Rui route 11 you
would say no I don't want all those
different varieties from the farm I want
SL 28 please thank you and then it's
probably going to be more unique and
interesting it might be more expensive
but that's the price you pay in terms of
processing obviously picking is huge
sorting is huge how long has it
fermented for and how what percentage is
it dried to drying has a massive effect
on meillard reactions in a roaster if
some of your coffee is wetter and some
of your coffee is drier some of it will
steam and some of it will cook and
that's gonna have a massive effect down
the line on your extraction so this is
all again unevenness unevenness
packaging usually that's okay because
it's all in the same if you buy a
container of coffee it's all packaged in
the same way but if it's shipped for a
long time and one end of the container
was in the Sun on the side of the boat
that's going to get cooked and then the
moisture is going to change the water
activity is going to change and then
even this is going to occur and then age
of course as well so there's a lot
against the green buyer to get evenness
in their coffee but these challenges
have been somewhat surmounted by good
practices and good buyers good farms who
understand what's going on but next we
have roasting so roaster design is
generally pretty terrible for cooking
coffee we're currently specialty coffees
currently using tumble dryers disguised
as coffee roasters and it's really just
like a massive beans at a 30 at a 20
degree angle sitting in a tub getting
spun around by some arms in a barrel
with some hot air coming over the top it
is not even if you showed that to a
process engineer or a chemical plant
engineer who designed you know mass
transfer or anything involving fluid bed
design they would laugh at you
because it's just so uneven the
application of heat to coffee beans is
horrific in drum coffee roasters so yeah
that's against us I honestly don't know
whose fault it is that specialty coffee
industry uses drum Roasters but whoever
it is deserves a lot of pain whoever
bought the first probe at or like I
don't know if Instagram was around then
but whoever did whoever did that yeah
they deserve some pain so we have
development and solubility if your
roaster is accelerating towards the end
of the roast if you have a lot of heat
being applied near the end of the roast
the outside of the bean will be more
cooked than the inside of the bean kind
of like a steak you don't want a charred
rare coffee bean that's delicious when
you have a steak but you really just
want like a awful boiled Suvi steak that
hasn't been seared that is optimal for
coffee and it's really hard to make that
happen in Drumm coffee roasters and then
obviously of course blending yes yes
absolutely if I I would you know the AG
tron color scoring thing the machine
that was actually designed for french
fries for McDonald
and it is a French fry machine and it
uses some specific wavelength of light
or near-infrared to measure the
development of certain chemicals in
coffee and normally Roasters will
measure the outside of their coffee
beans they'll put the beans in a tray
and slide it in the machine it measures
them then they'll grind the beans and
put them back in and now measure the
difference from internal to external
color and a lot of specialty Roasters
pride themselves on having a big
difference between those two numbers and
it's just underdeveloped and savory and
awful those those numbers should be
theoretical identical otherwise you're
just inviting unevenness and if you have
an even roast then you can choose to
move it darker or later but if you have
an uneven roast your freedom of movement
of where you could have moved an even
roast darker or later your freedom is
now there now whenever you make small
adjustments you're gonna be very
frustrated so you want the inside and
the outside to be identical which is
hard but if you can get there then you
have so much more freedom and you're
making coffee that tastes so much more
delicious it's really hard with the drum
Roasters Jeremy challenger from prufrock
who I just hired has a wonderful analogy
for roasting he says roasting and drum
roaster is like throwing a porcelain
vars onto a shelf on the top of the
bookshelf and it has to land on the top
of the bookshelf without breaking the
first time and you don't get any
practice rounds and it's kind of right
because it's so difficult to cook a
little coffee being the right way and
then people blend and they'll
deliberately Brett blend a Brazil and a
kenyan because they're like I want a
chocolaty coffee that's also fruity but
one of them super dense and one of them
is super not dense and they'll roast
them pretty similarly and then you'll
have massive unevenness once again
reducing your freedom to move around and
your Brazil will be over extract your
Kenyan will be under extracted and your
actual you know average extraction is
somewhere in the middle and it's just
not going to be great so roasting adds
another bunch of fun things to evenness
I can't wait for specialty people to use
more fluid bed roasting yes
that's even worse I didn't even bring
that up yeah if you yeah no absolutely
because it's cheaper in it and easier to
just like pre blend yeah yeah that's
true actually if you yeah if you pre
blend you're green that's just adding
even more problems because if you if you
were really good at blending you would
match the solubility and porosity of
your different blend components by
roasting them differently perhaps two
different times or temperatures and then
they would match each other once you
started brewing them and if you actually
focus on that you the blends you start
to make taste so good but the amount of
effort it requires to consistently match
porosity and density of different
coffees in a tumble dryer is like way
too much effort
so nobody does it let me just kind of
like hope that we're close yeah I'm
gonna I'm gonna get to that later yeah
because that's that's a new thing that
we've started figuring out properly so
then finally his grinders and grinders
is we're going to sit for a while
because that's probably what most of you
have control over and what you can
understand and what you can manipulate
most of the time I'm sure there's a few
Roasters here but everyone here I'm sure
uses grinders and has it at least a
little bit of an understanding so
extraction is an average and that's why
it's really hard to understand it is not
just a number that comes out of a
refractometer and that's also why most
most of the criticism I hear about
refractometers
is that it is just an average therefore
it'll never tell you what's actually
going on but an average will at least
give you an idea of more or less and
that's really important so when you have
a lot of different grinds coming out of
a grinder you have small ones bigger
ones way bigger ones on a 2 or 3 orders
of magnitude in terms of microns the
smallest ones have so little mass and so
much surface area so their surface area
to mass ratio is so out of whack that as
soon as water touches it it's fully
extracted
there's almost nothing left to extract
whereas when you have a very large
coffee grind that really taught us
tortuous matrix of cellulose is hard for
the water to get into it's not just
gonna freely dive in and then come back
out again and if you want an example of
that through some coffee beans in hot
water and see if you get a pour oh it's
not going to happen because the water
doesn't get into those coffee beans so
our extraction is going to be made up of
completely extracted tiny grains less
extracted slightly larger grinds and
very very under extracted large grinds
and as you'll find out soon because of
the way spheres work this completely
blows out of proportion once we start
grinding with regular coffee grinders
and it's a real hassle to actually get
full extraction out of our coffee grinds
because of this problem so this was
actually the little card that I printed
out for the judges at the 2013 world
Barista Championship when I used an ek
43 for making espressos I was like I
don't think espresso grinders are
probably optimal for extraction
because of this and its really obvious
you've got a whole bunch of pebbles
coming out of an espresso grinder and a
whole bunch of dust and with a filter
grinder you have a whole lot of really
small coffee grinds and the first time I
ever made an espresso with an ek 43 I
hit 22% extraction whereas I'd been
struggling to hit 18% with a roba and I
didn't do anything weird we didn't
change the grind we didn't change the
machine we just presented the water with
so much more surface area and so much
less big grinds that our extraction
yield went up and the coffee tasted so
much better so this is a really basic
example you know a really big
contrasting example of why it's better
but we're gonna dig in a little bit
deeper and start to really understand
what is better where does it become
better and why and how does that change
occur with
different grinders so this is a classic
particle yes no that would cost a lot of
money but you can choose equipment and
brewing practices that reduce the need
to do that kind of stuff and I'll
definitely get into that later so this
is a classic particle size graph that
would come out of a device called a
laser diffraction particle size analyzer
so what it does is you grind some coffee
grinds chuck them in this machine
it sucks on the through with a vacuum
shoots lasers at them and because of the
magic of physics it measures the
diameter of every single particle which
is pretty neat because I wouldn't want
to do it by hand so it pumps out a graph
like this now on the at the join of the
axes would be zero microns on the x axis
all the way up to that's probably a
millimeter and this is a logarithmic
graph so if that's zero and that's a
thousand then that would be 10 and that
would be 100 microns so it's a scale of
10 a log scale so in this particular
example on the y axis is percentage or
percentage volume and you can pretty
much just say there's more or less of
them like that's the easiest way to
think about that y axis so we have in
terms of volume not in terms of count
this is just how much space do they all
take up cumulatively
we have very little 0 to 100 micron or 0
to 10 micron grades we have some up to
100 we have lots of volume between 100
and 1000 and that's pretty classic for
most grinders and that's a problem so if
we put in this other line here here
you'll see that it's very different in
terms of the 10 to 100 micron range
and it's missing a whole heap of the
probably 400 to 1000 micron grains at
big empty space up the right-hand side
there now for the longest time everyone
in the coffee industry would say the
black line is superior because it has a
taller peak and everyone was very
focused on the peak the peak the peak
the peak and it turns out that the
height of the peak of whatever your
chosen grind setting is isn't really
important what's really important is
what's your total standard deviation of
every little extraction that's happening
from all of these grinds so how big is
the distance from your most extracted
grind to your least extracted grind and
can we manipulate that so with this red
line we've reduced that standard
deviation now this is really important
the reason we want to move this line to
the left instead of eliminating all of
this and moving everything to the right
and making more coffee up in here is
because these little grinds down here
act and brew exactly the same way as the
exterior of all of these so a big grind
doesn't all extract at 13% it extracts
at an average of 13% because the outside
is at 28 and the inside is at zero and
halfway between zero and 28 is 14 so
that was a bad example but 13 14 14
percent that's why your big grind is at
13 percent extraction it's not because
big grinds extract at 13 percent it's
because water only penetrates a little
bit into the big grind leaves the rest
alone destroys the outside and then
leaves and then your average is 13 or 14
so if these guys all down here are
behaving exactly the same as the outside
of these grinds then really we should be
optimizing everything to meet your
maximum so maximum is actually great
because you were already extracting all
of your grinds to maximum it's just that
your average of what you were missing
the inside of those grinds was dragging
your average down
now I'm gonna re explain that in about
five different ways over the next 15
minutes to make sure that you all
completely understand what I'm talking
about now the most optimal grind would
be like that and that's what you would
see from something called a roller mill
that they use to grind for like a
Nespresso capsules and high-volume
industrial grinding and that's an
extremely even very fine grind size
where everything is extracted to 26% and
it tastes amazing but unfortunately
they're really expensive and they're
hard to fit into a room like this so
it's not exactly an ek 43 so we just
have to try and get there we just need
to try and optimize our grind and use
brewing methods that move us down that
way so that we can approach that optimum
so I'm gonna explain it another way
instead of looking at a graph we're now
going to pretend that coffee grounds are
two-dimensional they're flat and the
waters on the outside and the coffee
grown is just like a circle so if we
look at a course a medium and a fine
grind in terms of we've sliced them and
we're looking at them as a cross-section
and we use black white to black as our
extraction zero being white black being
28 or maximum extraction you'll see a
tiny grind is completely extracted
twenty-eight percent probably 25 percent
but 20 28 percent is our theoretical
maximum and the really fine grind only
has a tiny little speck in the middle
that hasn't been extracted a lot the
rest of it is completely extracted now
you notice that that thickness is the
same in the medium grind but because the
medium grain is larger there's more of a
space in the middle that has been less
extracted so therefore the average
extraction for your medium grind is less
but the outside still has the same level
of extraction as
this fine ground and then as we go
course you'll see that thickness is
still the same but the inside is so
large there's such a large proportion of
that ground that hasn't really been
extracted that the average is taken down
again now cast your eyes to the colored
band this is what everyone thinks
extraction is in terms of good and bad
on the same axes so because of this
average phenomenon where our extraction
number is just a mixture of everything
what it leads us to believe is that zero
to 18% is under extracted eighteen to
twenty three percent is great and then
above twenty three percent to twenty
eight percent is over extracted and
that's an illusion because of that
average effect what really happens on
what I strongly believe is the case is
that it's more like this if you actually
measured every grind to see how it was
extracted and you could isolate it
correctly everything up until eighteen
percent would be under extracted
eighteen to twenty three percent would
still be under extracted and then 23
percent to 28 percent would be correctly
extracted because remember the outside
of our grounds are all being completely
fully extracted every delicious coffee
you've ever had the majority of the
flavor you're tasting is actually at 28
percent extraction or whatever is
maximum for that coffee because the
external area of all of the grinds in
that brew that you thought was delicious
were at maximum they were completely
extracted and any number that if you
measured that coffee in at read twenty
two percent what you're really saying is
I really enjoyed this coffee because
some of it was extracted to 28 percent
but there was some that the water missed
so the average extraction is probably 22
so full extraction is actually optimal
yes there is over extraction and that's
why I stumbled on the over extraction
column of the previous slide because
over extraction does occur but you
really have to try and I'm finding more
and more
or that the flavors that we associate
with over extraction you really have to
try to get them and normally it's all
this coffees bitter and dry
must be ever extracted you're roasting
sucks is usually what you know that
reason is or usually what that symptom
is for and you know dryness emptiness
you really have to sit well roasted
coffee in a boiling saucepan for two
minutes to achieve over extracted
flavors or you have to run an espresso
four minutes but if you roast coffee
perfectly and push water through an
espresso machine push a filter coffee
ratio one to sixteen through well
roasted coffee grinds in an espresso
machine it's still not over extracted so
over extraction probably doesn't really
matter that much it's probably your bad
roasting or bad coffee quality or you
were making a brick coffee and left it
in the sand for too long but I think
it's very rare that anyone has actually
tasted truly over extracted coffee maybe
little bits have been ever extracted if
you channeled an espresso and then all
of the hot water was just going through
a tiny little bit that channel has
probably been well over extracted but if
you're evenly extracting I think it's
pretty much almost impossible to
completely over extract the coffee and
this is really counterintuitive and it's
taken me a long time to even like poke
my head up and be like maybe this is
actually what's going on because I
usually get usually get shot down by a
lot of people but this is this is I'm
pretty convinced what's going on and a
lot of people are now becoming convinced
are the same thing yes maybe yeah I
think there's so much pressure from the
water once you actually I'll start
brewing that tamping pressure is a
little bit of relevant because there's
like 100 and what is it hundred and
sixty no 115ps i-49 bar it's like if you
could tamper 115
so I'd be like guns gun show the
pressure from the water I think
completely nullifies any light tamping
that you were doing and just brings it
to max so yeah I'm not sure so I did a
little experiment because I was like
maybe I'm wrong
so that's science the hell out of this
so what we did was we used a sifter and
we sifted we ground some coffee and we
made three fractions of grind sizes they
were 0 to 250 microns or what I would
consider to be very fine particles any
finer than that and we would have been
sifting all day then we had 250 to 500
microns and then 500 microns plus now a
micron is one one thousandth of a
millimeter so 500 microns is half a
millimeter so this is pretty small so
what we did was we measured out the same
weight of each of those different size
ranges put them in cupping bolts and
then poured boiling water on them the
exact same amount of boiling water on
each of these little cupping balls
stirred them vigorously and then in
different cupping balls so it didn't
take samples from the same bowl we did a
specific Bowl for each time we took a
sample of the liquid and then measured
the TDS so this is a pretty good way of
understanding how water penetrates a
grind and what it does and when it
actually starts to come back out again
and give you flavor so at 15 seconds
which was my first Waypoint the five
larger than 500 micron grinds were at 14
percent extraction the 250 to 500 s were
at just under 20 and the 0 to 250 were
at just under 23 and then we measured
again at 30 seconds and the largest
grinds had jumped up to 17 the middle
fraction was just above 21 and the
smallest grinds had only increased a
little bit from maybe twenty two point
eight to twenty three point eight so
maybe 1% more now after that the
smallest grinds barely moved again
the largest grinds had also started to
plateau quite heavily so what you would
expect to see with the large grinds is
that line continuing to go up to meet
the smallest grinds because you would
expect that the extract the water would
go in deeper and deeper and get more get
more coffee and then come back out again
and contribute all of those solubles to
the brew but it didn't it just kept on
lagging and I kept on going
oops all the way up to 10 minutes or 600
seconds and as you can see the 250 to
500 microns eventually got there so the
water in that case eventually got in so
at the maximum size 500 microns it had
traveled in 250 microns because that's
the radius from the edge to the center
of those grinds assuming they're
spherical which is the only thing we can
assume and then it traveled all the way
back out again and eventually we got to
this the same level of extraction as the
smallest grinds but it took 10 minutes
that's why cuttings
I think taste so great is because
they're probably more evenly extracted
because we gave it so long to extract
now the largest grinds were still only
at just up just above 19 19 and a half
percent extraction after all of that
time which means the water hadn't even
touched what was happening on the inside
so this isn't super obvious like sorry
this isn't super new like we anyone
could have predicted that the large
grinds would have a lower extraction
yield than the smallest grounds but what
this data showed us was that the outside
of the grinds and that first layer
that's been penetrated by the water
behaves exactly the same no matter what
the diameter of your coffee grinds if
you do some quick math and figure out
what the depth of extraction is because
if we assume the smallest grinds have
been completely extracted and our
maximum is 24 then you can figure out
how based on how big the grind particles
are how do
the waters gone in because if they're
the same density the whole way through
and you've extracted half then you
figure out what half the volume of that
sphere is in terms of a ring around the
outside and then you know how deep the
waters gone and it was really really
eye-opening because at every single
point where we compared the different
fractions of diameters the water had
penetrated 100 microns almost every
single time within plus or minus 10
microns it was it was going in 100
microns doing its thing and not going
any deeper and that's it so if we look
at our grinds again from that previous
example this is really what we're
extracting from every grind is a layer
now again we're assuming they're
spherical and this is a worst case
scenario so it only gets better for this
argument if they're not spherical which
is great we're only extracting a hundred
microns deep in all of those different
coffee grinds and then the rest is
wasted so that means that the optimal
grind setting absolutely optimal would
be 200 microns maximum which is
ridiculous because any broad would clog
instantly so like that's that's beyond
my paygrade yeah we were staring the
hell out of it the whole time yeah
because the cellulose is still there it
does continue to extract and that's why
the largest that's why that blue line
down the bottom continued to increase
because you had erosion occurring and
that's why you see at a certain point in
the espresso extraction your water flow
it sort of goes quicker and it starts
slow gets quicker and then plateaus and
once it sort of hits that plateau of
flow rate that's when you've eroded
everything that you're going to erode
and now it's just water flowing through
cellulose this is probably because
stuff's eroding 30% of those tunnel
walls have been eroded now the tunnel
walls a bit no the tunnels are bigger so
the water can get in more easily so
that's that slow increase that we're
seeing there probably other things
happening as well but it's not the water
just doesn't travel into a maze because
it feels like it yeah yeah yes
I have no idea yeah I think co2 probably
gets in the way of extraction when it's
really fresh because there's all bubbles
and stuff everywhere especially in
espresso because because we would I
think we normally trended when we were
capturing data from all our espressos
every day the older it got the higher
our extraction yields got I think was
the general trend was there it yes big
glorious yeah yes oh my god yes so much
less yeah but I'm not saying a hundred
microns I'm saying 200 because it's a
radius so the water can go in to the
middle and then come back out again and
it's probably more it's probably like
250 yeah and it also really depends on
how you roasted the coffee if you if you
smash it with a really high temperature
the bean will expand more there was a
guy who did rad experiments back in the
80s where he roasted coffee and then
injected it with mercury to see how
porous it wasn't what the internal
volume was like a real mad scientist
and he found all kinds of cool
things about how roast effects the
expansion of the bean so I would hazard
a guess that if you were a roaster if
you started measuring volume and you
were aiming for maximum volume increase
without roasting too dark your porosity
would be increasing because you've got
the same amount of cellulose it's now
bigger so your porosity would increase
now this coffee that we tested was very
like it was roasted by onyx in the US
and they are they're on the lightest end
that I would enjoy and that means that
it's probably going to be a lot less
soluble so this rule is only for this
coffee in this particular way in this
experiment and if you change the
roasting you might find that you've got
a bigger window that you can play with
in terms of that depth that the water
can actually penetrate the grinds yeah
like way more pores yeah and that's
usually the case because a lot of people
try to under X tracked dark roasts
because they're so eat there so soluble
and so red
be extracted and I need to do way more
testing to actually figure out what is
the spread where's the where's the
average where does it go to it's really
early days and I'm sure labs have done
this properly but we're just like you
know four people in an office in
Melbourne yes yeah it was them it was
the coffee we sent out for the
subscription it was a Guatemalan which
means it was probably cateura from finca
in Seoul it was just the tasty coffee we
had on hand in the officer at the time
because we were sending it out but I'm
not saying that everyone has to grind
superfine tomorrow and that's that's the
problem here is that we can't just
change how we're grinding our coffee to
make them more really small because
everything in clogged and it's not going
to work so if we have a look at these
electron microscope images either off an
electron microscope images you can see
these little bars here or a hundred
microns and it kind of gives you an idea
for how deep the water is actually
penetrating into these grinds and you
can see based on the cell structure of
this coffee how the cell structure and
those pores really defines how the water
can get into the coffee because coffee
isn't this beautiful crystalline
substance that's just endlessly
repeating and perfectly dense it's
really gnarly it's got little holes and
tunnels and bits and bobs and coffee
flavor hanging off walls and it's not
optimal for water flow it's possibly the
worst thing for water flow and this is
even more zoomed in that's a hundred
microns again that that white line
that's how deep the water's getting in
that experiment you know it's a couple
of pause maybe it gets into one poor
finds a hole gets into the next one it
stops that's it so it's really tricky
for water to get into this stuff it is
not designed for that so essentially
what I'm saying is over extract
isn't really a thing it exists yes and
it tastes awful yes but you're probably
not going to encounter it what you need
to do is always aim for more extraction
now every time I say this someone goes
but more inspection doesn't always taste
good and that's because what you're
normally doing is you're measuring your
coffee you're grinding to fine tasting
it again seeing that the extraction went
up a little bit and saying that over
extraction is bad and you shouldn't aim
for more that's like one case in this
entire multi-dimensional sphere of how
to make coffee extracted more yes it can
taste worse when you increase your
average extraction but if you understand
how averages work then you need not be
scared about increasing the average if
you do it in the right way so the bad
way to do it is to grind so fine that
you end up going backwards so this I
took this up on the blog years ago as
you continue to grind finer your
extraction will go up obviously of
course it will and then at a certain
point you hit the maximum amount of
extraction that you're going to get with
that brewing device that coffee that
combination variables and as you
continue to grow and finer you're going
to go off a cliff and your extraction is
going to go back down again so you need
to find that little maximum that local
maximum it's not a local maximum it's
the maximum extraction that you can get
from that coffee and that is always
going to be the best tasting coffee in
my opinion maybe you like under
extracted coffee that's cool I think
that's going to be the best tasting
representation of that coffee that you
can possibly serve is that that maximum
point now a lot of people as I said
complain that it doesn't always tastes
better when you increase the extraction
I would argue either that you're
roasting sucks you don't have a pellet
or if you're doing it the wrong way
because it's always better so this is
what's normally happening when people
they have an uneven extraction and they
say Matt you're an idiot extracting more
is just going to make it taste bitter
and awful what they're already doing is
that uneven extraction that I was
talking about before this is one coffee
and as we've learned it's
not a melange of under extraction
spreading evenly through to over
extraction it's under extracted
internals of groins and over extracted
externals so that's represented with the
same colors as before but we have this
line here where it's not not tasting
great it's kind of over extracted and
it's not good if they increase the
extraction of this coffee that has to
move even further into the depths of
over extraction before the bulk of their
coffee or it may be half of their coffee
even begins to become well extracted so
of course you would argue that
increasing your extraction is bad when
it's uneven because it's already so
close to over extraction and not tasting
good and also already so under extracted
at the same time that you don't have any
freedom to move and you're kind of stuck
so of course you don't want to increase
it and if you make your extraction quite
even then it's going to be sitting
somewhere in the middle you've combined
both of those you've doubled its size
and it's now sitting in a reasonable
level of extraction but because you've
reduced the amount of space that it
takes up on that extraction axis you'll
now free to move that tiny bubble of
coffee extraction up or down which means
you can bump it all the way up I don't
know what's going with this slide all
the way up to as close to maximum that
you possibly can
and then you're using less coffee you're
extracting more of it it's more sweet
you have less under extracted you have
less over extracted and it's just more
generally delicious
so once you understand that improving
the evenness of your coffee to produce
more extraction is great then you really
open up an entire new realm of
deliciousness and it's far more freeing
than any other variables that you can
adjust so I have practical tips yes I
made a at the mal Koenig Factory in
Hamburg I got to play with their giant
industrial grinder that has burs about
like that big I think it's called like a
DK 27 and it does tons and hour
and we put in a little 20 gram dose in
the top and it was like just just
disappeared we got three yeah we got
three grams out but we dialed it in and
got 26% and it was it was otherworldly
it was bizarre but I've had similar
levels of extraction at in espresso
which is frightening from roller mill
grinding as well
I felt like single-serve pods and things
like that
so in terms of brewed coffee you need to
treat every grind the same way imagine
that you've got a wonderful democratic
republic and every single one or maybe
socialist and every single one of those
grinds needs to be treated exactly the
same way all of them and they need to be
the same size and everything needs to be
fair agitate and stir
you're not gonna over extract a filter
coffee by stirring it at the beginning
that's absolutely ridiculous
you're extracting it for three minutes
stirring it at ten seconds isn't going
to do nothing except make your
extraction more even which is going to
make it more delicious agitation and
stirring is to get every grind wet asap
so just get everything wet if you see
bubbles later then something was dry and
has just become saturated and released
co2 that's a really great indicator in a
pour-over or a cupping bowl or whatever
that not all of the grinds were wet
don't grind so find that flow is choked
because there is that maximum and that
decline again you need to find the max
that's as fine as you can go and if you
do want to sift he's gone the sifting
that is gone there is if you want to
sift I would recommend sifting
everything larger than 500 microns
because that's the fastest sifting you
can do because I will just pass straight
through and then the boulders are left
behind there's no tapping and shaking
and all that kind of stuff
everything just drops through a 500
micron sieve except the worst offending
boulders and you then you can regrind
those if you're grinders appropriate for
that and you'll improve your coffee to
no end instantly in terms of drip I
didn't have time to redo this but I
recommend flatbed Brewers more than the
cone sort of shape because there's no
reason the water
wants to travel all the way down to the
bottom of a cone that seems a little bit
prosperous but flatbed at least if the
water is flowing through one part of the
coffee it has the same level of
incentive to flow through every part of
the coffee just seems to make more
simple sense
so W dose and stirrup that's easy
make sure the grinds are up on the edges
make sure the water levels never too
high because then it just wants to go
through the paper if you can get if you
were water and you have the choice of
going through coffee or paper you've got
you
you go through paper which so don't pour
too high
keep your agitation and level the same
like I see a lot of Brewster's whipping
their little kettles which is very
inconsistent just keep it a consistent
height and let gravity do the pin drop
for you in terms of batch brew if you
need to turn off the sensor if you have
a new fedko so that it doesn't turn off
when you take the basket out there is
options for that or trick it by like
cutting out the magnet and gluing it to
it there's ways and make sure that the
number of pulses keeps the coffee wet
but the bit the water height never too
high like you don't want to have three
pulses that completely over blow the
basket and then take forever to drain
out you want to just be constantly
delivering nice hot water and keeping
that level just sitting above the grinds
there is always a minimum dose in the
batch Brewers where and once you grow
below that minimum dose the water just
goes through the sides and there's no
reason for it to go through the coffee
it's really weird way the water delivery
in batch Brewers this has nothing to do
with the rest of the lecture but nobody
actually weighs what comes out of that
batch brew and there trust what's on the
screen it's wrong so weigh at least five
and then each day way to and an average
it and that's your brew water wait for
the day and then measure it when the
dishwashers on and be depressed because
it'll be less and generally with batch
brews just grind coarser and I know I
didn't say to grind course you have to
grow in finer but the problem with batch
brew is that there's no there's no ins
there's no pressure pushing that water
through finely ground coffee
if the water can go out the side it'll
go out the side so you need to make it
as easy for the water to go through the
coffee as it is
through the paper so that's pretty
coarse in terms of immersion dump the
water in as fast as you can so that the
dumping of the water stirs the grind so
you don't need to carefully you know
drop water in just dump it and then
that'll agitate everything for you
stir it but don't leave it spinning I
find with arrow presses if you leave it
spinning some grounds will be sat still
and others will be whizzing around at
the top and they're going to be more
extracted than the ones that are still
down the bottom marginal gains every one
increase yeah use two papers for an
arrow press it's always better and the
usual inversion is fine
now for espresso I everyone thinks I get
paid by VST but he's so stingy
he doesn't give me a cent VST baskets
way better than everything else just use
them that's so cheap and they last
forever
they don't last forever they last for a
very long time if you have a curved
tamper put it on the Shelf it looks nice
and get a flat tamper because your
extraction will become uneven with a
curved tamper because water doesn't like
going through not flat things evenly
fill your hopper up with espresso
grinders if the bed depth of the coffee
before the birds is different than your
particle size distribution would be
different
that's a mad design error and then
distribution I still have no idea what
the best distribution method is we
released some results for that the other
day some of you might have read it and
we discovered that using the OCD tool
kind of spinny things is better than
doing nothing but it's just as good as
the free method of just like tapping the
portafilter with your palm
which is a little just a little bit
cheaper than 2-hundred what is it a
hundred and twenty quid or whatever it
is over here but we're working on what
is optimal and how do we get there
rather than just that doesn't work let's
do something cheaper yes that's what we
need to do next we need to test ten
Muppets sorry baristas and see and see
if they can actually do it consistently
and then we also need because the other
problem with the testing was that
everyone who sent us a distribution tool
for testing said we're not claiming that
it does anything but here it is for
testing so so if it doesn't work we
didn't say it worked but if it did do
something that'll be great if you could
tell everyone and they also said and
make sure that it's evenly distributed
before you use the tool so to test the
OCD based on what they recommend to use
the OCD with we literally had to do
stock filleth before or whatever that is
before we use the OCD so anyway
it's all very silly what we are working
on is this silly thing which looks like
a murder weapon that kind of like
punctures the coffee and it's not it's
not as much about needles making paths
through the coffee as it is adding so
much volume to the bed of grinds that
the grinds have to move to accommodate
them and they move sideways because
there's no reason that they they can't
move down and they're probably not going
to move up unless they have to so we're
kind of calling it sideways tamping and
honestly I think it's the silliest thing
when you took when you just like move
this thing that sticks holes in the
coffee but on most of our tests so far
our extraction yields increased by two
percent which is the largest increase
I've ever seen since using going to a
good flat burger rinder or moving from a
curve to a flat tamper so I don't care
what it looks like if it does the job
and it increases their espresso
extractions by two percent and wins
every blind tasting that we've done so
far it's doing something so I'll sell it
and it'll make your coffee taste better
if you want to use it but that's we're
still testing it
still trying to figure out exactly what
it does and does it not work in some
cases as well so we're still a little
while away from actually releasing it I
still have no idea if the sideways
tamping thing is even real or not but if
blind taste tests and extraction yields
are consistent across the board we will
start manufacturing something like this
and it's obviously not for high volume
cafes that's an ugly prototype version
that we just busted out in a week it'll
look much better than that but if it
does work will release y-you know we
think it works and people can choose for
themselves yeah it's a weird thing
espresso
app so gameplan from now on after
tonight is more extraction that's pretty
obvious even more extraction than you
just did until it's worse and then take
a little step backwards so always more
always more more more more more more
more more more more until it tastes bad
and then dial it back a little bit and I
promise you that's the best cup of
coffee that you can possibly make so
that seems pretty simple now here's the
silly part of tonight it's all been
value up until now we just released an
online course that is pretty much the
stuff I talked about tonight in detail
and we go into algebra in terms of how
to manipulate all the different aspects
of a coffee brew we go into extraction
theory we have spreadsheets and
calculators and tools and all kinds of
stuff this is what barista hustle is
mainly sort of going to be focusing on
now is online education and I think
there's already 400 students in there
that have finished or already started
the course and we're getting we're
getting very good reviews and we're
continually updating as people ask
questions so it is more like a living
document this first course so that's up
and available get your managers to buy
it for you or we're going to continue to
offer more courses we want to get into
doing a barista or cafe financial
literacy course and try to tailor it to
each major sort of area so that if your
baristas or if your managers or cafe
owner
and your staff have done a course like
this hopefully they can make your
business more profitable and everyone
can make more money we want to do a
advanced espresso course so this is a
what we talked about tonight was kind of
like a meta-level extraction not
necessarily filtered not necessarily
espresso we want to do an espresso a
specific course that goes super deep we
have a lot of research equipment
arriving for so we can actually figure
out what the hell's going on with
espresso we want to do a filter coffee
course all kinds of stuff because it
turned out that releasing things for
free on a blog is cool but releasing
everything for free on a blog it doesn't
pay any salaries and leads to things not
going places because that's how the
internet works these days so we decided
to change tack and go down the very
professional very advanced courses
online and certification route because
education is pretty lacking in the
coffee industry and you don't have to do
it but I think they're pretty good
courses and they're pretty advanced and
relevant compared to a lot of the
incumbents that are out there at the
moment so that's the little silly part
of tonight
now if the questions now I have a rule
about questions at question times it
talks if your first sentence doesn't
finish with a question mark you've
surrendered your question that's the
rule if there was a second sentence then
you also surrendered your question yeah
we're we don't there's the rest of the
people in this room don't want to hear
your story and question time isn't
necessarily about sounding smart because
you asked a smart question it's about
figuring stuff out
so many questions sessions get derailed
because everyone wants to show everyone
how smart they are by answering the
question they already know the answer to
but I'd much prefer to answer questions
that you don't know the answer to
because then everyone learns so I'm yeah
anyone anyone can ask anything if you
like yes
worst water London's up there but I
think Copenhagen takes the takes the
winner for the worst tap water
it's like 1,200 ppm it's like more than
Evian it's a lot of stuff in your water
like that's ocean
oh oh she annek you don't need that much
for dark roasts not even not even maybe
two orders of magnitude less would be
acceptable still yeah we we've got a
bunch of different have you read the
articles that we put up about water
chemistry and just start experimenting
with that we we made a chart with lots
of different points and different
combinations that represent different
standards but also different cities that
have coffee good coffee cultures and you
can start experimenting by with two
concentrates that we designed so that
each gram of concentrate equals one
milligram per liter of the eventual
chemical and if you start playing around
with those with one coffee and making
different different water recipes you
can really start to understand how the
knobs on that extra sketch actually move
flavor and you the only way to do it is
just to do it yes just give it a crack
it you know take get a couple mates buy
some bath salts have a bath party
afterwards or something have a spa and
just just have some fun yeah yes
because calcium making calcium into
solution is really hard unless it's
already it's what is so weird if it's
not already in the water and it's like
slowly dissolved in there over eons and
that's a natural water source
you can't just jam calcium into water
it's really hard and it screws up other
chemistry's as well it's like you do one
thing in water and then ten other things
will change and then you have to like
it's like herding cats every time you
change one variable so the magnesium
most people who have played around with
coffee chemistry and have played with
cat played with magnesium have been like
actually magnesium tastes a lot better
than calcium does so we figured for ease
of use go to the hardware store pick it
up we just go with those chemicals yeah
ease of use what an exploration was the
biggest thing that we wanted to do there
for sure yeah cool anyone else yeah at
the back well they they they do that in
roller mills because a roller mill will
usually have three sets of rollers so
it's double regrinding I would reground
boulders after you sit at them out but
generally I would advise against tree
grinding because the amount of torque
required by the grinder motor to re
grind grounds and get them through would
normally stall the motor and if your
grinder isn't designed correctly that
will damage it or it'll overheat or
something will happen and regrinding
grinds means that there's grinds where
there were beans in the pre grinding
stage and then it gets really messy so
yeah I don't know it's not great just
grind finer yes
yes are you struggling to get it slow
enough is it going really quick and
you're it find the finest sitting your
birds are not aligned so you need to
need to align your burrs at the moment
they're like this and they're sort of
spinning off axis and that means that
you're getting a mix of fine and coarser
grinds if you make them parallel you can
make them on average get a lot closer so
we have a guide for that as well well
now I think a youtube channel or
something on how to align them with
shims and takes about an hour and it
sucks but it's totally worth it because
your coffee will be instantly better and
more even and taste great and you'll
have more freedom in terms of the grind
setting you can use absolutely yeah and
especially if you're at the finest
setting that means something's wrong
you should be at about 2:30 to 3:00
o'clock
wait no three o'clock is maximum no just
after 3 o'clock maximum you should be at
like 2:15 at 2:45 o'clock yeah 1:00 or
2:00 o'clock
sure yeah was there customary yeah once
once it tastes good yeah now because
every every coffee day gas is slightly
differently in how you roast it as well
so whenever it tastes good yeah yeah
there's a lot of masturbation around
roast date optimal roast date time and I
think is could be simplified to when
does it taste good yeah neat yes yeah we
usually run it like whenever we do
anything like stats related or protocol
related we run it past some peers it's
not a form of peer review process and at
the moment we did start looking into
that and I am an author on a paper with
about grind
besides analysis but the I think the
amount of value that I can or that we at
barista hustle can create and the speed
at which we can move in terms of just
dabbling in different things to see
what's going on how can we optimize this
very quickly how can we optimize that we
can probably do ten to a hundred times
more value we or we can create ten to a
hundred times more value for the coffee
industry by being a little bit quick and
reckless honestly compared to very
formal peer-reviewed stuff which is very
slow and yes our you know our P P would
be closer to 0.05 or you know we improve
it if we did heat morsel sample sets but
I think there is a balance of how quick
and reckless we can be this isn't
medicine so we're gonna kill anyone I
hope and I think that we can create a
lot of net utility by doing these
experiments the way we're doing them
asking couple scientists is that do you
think this is ridiculous and they're
like now give it a crack and then
publishing those results are moving on
we can help a lot more people and move
things a lot more quickly and if UC
Davis and SCA want to like formalize
stuff afterwards and you know lock it
all in great but yeah we're I think
we're creating more I'm just trying to
create value like every meeting we have
unlike more value how do we how do we
you know move things forward quickly and
peer-review and like formal stuff like
that because it is so structured and
there is such a process that you have to
slowly go through it just slows things
down and we wouldn't be profitable
anymore we'd have to start getting
funding in other ways and everyone he'll
be bored because I do in the same speech
for three years because that's all we'd
be able to focus on is the one paper for
three years or whatever it was so I wish
that it was easier to do peer-reviewed
you know like published papers that'd be
amazing but expensive yes
yeah yeah I mean acrylamide is a
carcinogen but you know so is everything
and there's background background
radiation in this room right now
that's probably killing us too yeah I
think California is probably the most
nanny state but also they've done some
pretty valuable stuff for citizens in
terms of protecting them like they're
pretty easy Ellis I would say
overzealous maybe but in but sometimes
they really like do a great job oh yeah
what I don't know what temperature is
acrylamide created at 2:30 or something
yeah I don't know I just keep roasting
even further and then it's gone yeah
right yeah I mean there's so many
carcinogens in the world and every week
another paper comes out that is a meta
study of coffee drinkers and each week
it veers towards it's gonna kill you or
it doesn't kill you and there's a lot of
other things that have a much higher
confidence interval of it's probably
going to kill you so I don't know it'll
probably be on BuzzFeed for a year
afterwards and then everyone forget
about it because they're not going to
give up coffee I mean there's so many
other products in the state of
California that have this product is
known to cause birth defects etc etc and
people are still chugging it so yeah I
don't know maybe sales will drop and
much what a turmeric lattes will take
off for a month I don't know yes
you may yield is in more water through
the coffee yeah but then you'll
sacrifice you'll have less strength yeah
and that's always the compromise you
know you've got your seesaw that you
want to balance on and if you're if
you're at the point where you're like I
don't want this to be any weaker and I
am grinding as fine as I can that's when
you start ruthlessly going through every
other possible thing you know how did we
distribute it how's the water going
through it did something else happen
what's the shower screen doing what's
the basket doing how did we you know and
just keep keep going keep chipping away
at how to make this more even and you'll
notice that your extraction and strength
simultaneously go up when you do a good
when you're at that maximum and then you
do a good job with other things like
distribution they'll both move up
together and that's a win yes well the
Arrhenius equation which is like the
basic if you increase temperature you
extract more stuff you know sort of
basic equation is every 10 degrees
Celsius as a rule of thumb will double
your rate of extraction so that's the
easy answer I mean make it as hot as you
can so it still tastes good because you
could pull faster shots and then you're
more efficient so great so if your
coffee starts to taste terrible at 96 no
matter what you do bring it down but if
your coffee still tastes great at 96
then you can pull faster shots and be
more efficient and make more money and
laugh all the way to the bank with your
I don't know five extra dollars a day or
something yeah sweet yes
I want California to put a food warning
on that before they put it on McCulloh
minds because that's like you may as
well just spit on the coffee if you're
gonna blow it yeah yeah it tastes less
like carrot when you do that like chef
tastes pretty bad normally it should
come out from the roasting like if
you've still got a lot of chaff in your
grinds after roasting than you probably
pros to light that's a very rule of
thumb but if you need to be blowing it
off then that's that's a problem I think
well there's not enough movement or
airflow in the roaster or something's
going on yeah what's the time Nick maybe
I think we're getting pretty close to it
we nailed it pretty fun evening nice