(bright music)
- Welcome to the Understanding Espresso series,
a series where we take apart on individual variable
in the espresso making process.
In the past, we've looked at dose in, ratio and brew time.
Today, we're looking at the most complex of the variables
in my opinion, which is the grind setting.
how fine or how coarse you should be grinding the coffee,
and when you should use your grind setting
to make an adjustment to taste.
Espresso is a lot of fun,
but it's also immensely frustrating,
especially when you're starting out.
And I would say, this variable is by far
the most frustrating of all of them to work with.
And I'll give you the reasons why.
And there's kind of three reasons.
So let's say you make a grind setting change
going a little bit finer.
In doing so, you'll expose a lot more surface area
of the ground coffee.
If you think about cutting an apple into big pieces,
there's not that much surface area,
but if you diced it down into tiny pieces,
you'd expose a lot more of the inside of an apple,
and the same is true with a coffee bean.
And so far, that's good news.
More surface area is very useful
for extracting more coffee flavor.
But when you change the surface area,
you also change the way that the grounds
interconnect with each other.
And when you tamp them down in your little pack of coffee,
the finer the pieces are, the better they fit together,
and the harder it is for the water to flow through them.
This will increase the contact time
between the water and the coffee.
So you have this one change to surface area
that impacts flow rate and contact time as well,
and that's a bit of a headache.
And then for an extra twist,
quite often, changing the grind setting
is a little bit wasteful.
Now, this isn't true of every single grinder ever made
but it's very true of many, many, many coffee grinders
people use for espresso.
They don't perfectly push out
all of the coffee that they grind every time
that you use them inside the grinding chamber
that houses the burrs as well as the exit chute,
you'll often find some residual ground coffee
and that was ground at a setting
maybe before you made a change.
So when you make a change,
you need to purge out some coffee,
to push out to these old grounds
that are sort of set at the wrong ground setting
with some new ones.
And that's frustrating
because some grinders need a lot of purging
and others don't.
But either way, that's coffee that you never get to drink.
That's coffee that you waste.
And so, changing the grind setting is frustrating,
but it's necessary.
Without grinding finely enough,
you can't do the extraction work that you need to,
to get all the good flavor out
using only a little bit of water.
And that's the kind of nature of espresso
because you want to use just a little bit of water
to have a strong, concentrated, thick, delicious,
gooey, sweet espresso at the end of it.
Now just quickly, I wanna go back
just through how we got to this point,
a little bit of history.
People worked out pretty early on
that to brew faster you had to grind finer,
that way this increased surface area
meant that those flavors were more accessible.
But quickly you get to the point where there was a problem.
Finely ground coffee is difficult to get water through.
And in the early years of espresso,
different methods were found to increase the pressure
that the water was pushed through with the coffee.
Eventually, with compressed springs,
we got to the kind of pressures that we use today,
around nine bars of pressure.
It's equivalent in strange money of 130 psi,
but ultimately, it's nine atmospheres of pressure.
And that is a lot of pressure.
That causes problems in espresso brewing.
Generally speaking, you wanna go as fine as you can
expose as much surface area as you can,
before you break the puck.
Espresso brewing happens at these very fine pressures
and they are dependent on resistance
coming from the coffee cake.
But at some point,
that very high pressured water may well find a channel
through which to run, an easier pathway.
And what happens when an espresso puck essentially breaks
is that it begins to channel
and more water begins to flow through less of the coffee.
Channeling happens in most expressos at some point
and to varying degrees.
But as you go finer and finer and finer,
you increase the likelihood of the channel forming
because you created such a lot of resistance
to the water pressure.
Now the grind is not the only variable
that dictates how good a job your puck does
of creating even resistance throughout the whole brew.
Obviously, the depth of the puck will play a role,
as does your puck preparation
and how evenly the coffee is distributed
before you tamp it down.
Often people will talk about over extraction
when you grind a little bit too fine.
I know I've done that too,
and we associate that word with very bitter flavors
coming through in your espresso.
Generally speaking, the puck as a whole
may not actually be over extracted.
The puck as a whole maybe under extracted actually.
But the areas around the channels
where water has flowed much faster and in higher volumes,
they are extremely over extracted.
So they've given up more flavor than we want,
and they've added that bitter harshness to the shots,
but you'd argue that's really more uneven extraction
than it is over extraction.
Or just localized over extraction
rather than total over extraction.
Because again, if you're measuring this stuff
with refractometers,
and looking at your total yields,
you won't see a big increase in extraction,
that incredibly fine grained, you'll actually see a drop.
And in the past, this actually pushed people
to experiment with a much coarser grind
than is typically used for espresso,
in a paper that was published,
and I made a video about that,
so you should check that video out, up here,
when you're done watching this one.
Now, I'm not gonna say you have to use very coarse grains,
because you end up needing to use a higher ratio
to get a more balanced shot.
But you do get a more even extraction
using these slightly coarser grounds
than you do using rare finely ground coffee,
but your end result does feel and taste
and have kind of different texture and strength to it.
So let's talk about using grind on much more practical way.
I would definitely use grind to first and foremost,
get my flow rate about right.
Let's say I'm looking for an 18 grams in 36 grams out
in around 30 seconds.
Well, I'm gonna use my grind setting
to get me to that point.
But once I'm there, I'm gonna taste it
and chances are, the tweaks I'm gonna make,
if the espresso is good, but not perfect,
are gonna be two other variables that we'll discuss.
If I'm still a long way, away from good tasting,
I say I'm still very sour, I'm gonna go finer again,
and see how that does,
even if it's outside of my original spec.
But if I get my grind setting approximately correct,
then I'm gonna make those little tweaks
with dose, with yield,
potentially with temperature in some cases but unlikely,
but primarily, I would suspect with my coffee in
and my coffee out.
They're gonna let me fine tune that recipe, pretty easily.
Now the reason I like to use grind like this
for the big changes,
but maybe not as often when I'm tweaking
is actually largely practical.
If you're a beginner or intermediate
in the world of espresso,
then I think making less grind changes
is probably an easier thing.
There's waste from purging,
there's just the general frustration
around making those changes and making them accurately,
especially if you have a new grinder
or you're just new to the process.
So I think big changes with the grind are good.
And also if you have a stepped grinder
where the steps between each setting are quite large,
then again, I would go probably for the finer of the two,
even if that means dropping down my dose
and that kind of stuff.
'cause I'm just more likely to have a good experience
that way than being stuck with a slightly coarser grind
that I might want.
If I lived in a world with unlimited coffee,
unlimited time and resources,
then I would use grind
to really, really, really make small adjustments.
But that needs a very good grinder,
a lot of patience and quite a lot of waste.
And I'm not sure that's great real word sort of advice
or recommendations.
So I would say, you're more likely to enjoy your espressos
and the espresso making process
if you're not throwing away a ton of coffee each time.
So at the risk of repeating myself,
use your grind to get close, get good tasting espresso.
If things are dominantly sour,
you need to grind a little bit finer.
If you're finding things are getting
a little bit too bitter and harsh,
or you're getting a lot of channeling,
then maybe come back a little bit coarser.
I'll summarize all this in a second.
I'll give you some basic rules for using grind.
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So to wrap up, I'll give you a few simple rules
to use when thinking about grind setting.
So rule one, once again,
use it to get in the ballpark of tasty.
Fix your recipe, don't vary that,
just use your grind setting to get to pretty good
and then tweak from there
using your other variables in the recipe.
Rule two.
Generally speaking, push it as fun as you can
before you start to see channeling happening.
Now channeling will be very obvious
if you're using a naked portafilter
and you'll start to see uneven flow in your basket
especially in the last third of the espresso,
but you can also see it in the spotted portafilter,
you'll just be looking for a sudden increase in flow rate
as coffee starts to gush out of their spouts
in the last third of the of the chart
or potentially the last half
if things have gone really wrong.
Channelled espressos tend to taste
a little bit weaker than you expect, kind of hollow.
They have this acidity coupled with this bitterness
that you get in the finish,
this kind of harsh biting aftertaste.
In the past I've even recommended grinding
from some grinders into a little collection chamber
or bucket or tin or something,
shaking out any potential clumps
and then dosing into your portafilter from there,
for this kind of a reason.
Puck prep is really important,
but going to fine will produce channeling,
kind of no matter what.
Rule three.
Only change one flow related variable at a time.
If you're changing your grind,
do not change the dose of coffee
in your bucket the same time.
You won't understand or get insight into the impact
of either one that way,
and you won't know what's gone right or what's gone wrong.
So if you're changing your grind,
keep everything else the same,
so you can understand the nature of the change
that you've made.
And rule four, purging is essential.
And it's better to purge and waste five grams of coffee
than it is to waste the whole dose
that you ground incorrectly, pull the shot off and waste it.
So if you are changing a grind setting, with most grinders,
five grams, 10 grams,
it really depends on the make and the model,
but just make sure,
you're getting nothing but the new grind setting
that you wanna test,
to see if it makes the espresso that you want to drink.
But now I'd like to hear from you.
How do you feel about setting the grind?
Does it freak you out?
Does it stress you out to change your grand setting?
Does it feel like you make a change and nothing happens
and then something happens later on
or you just feel like
you chase it around and around and around and around
and you never get where you wanna go?
And I'd love to hear from you, down in the comments below.
Let me know which bit of this spoke to you,
let me know what you want me to go into,
in further depth, in the future.
But for now, I'll say thank you so much for watching,
and I hope you have a great day.