Today, we're gonna answer a question that I admit
at first seems pretty ridiculous.
Is immersion brewing
better than percolation brewing?
Is something like a French press, therefore
better than something like a pour over.
The reason I wanna do this is a few things
have been bothering me
at the back of my brain
and I've gotta make sure I need to scratch.
I've been thinking about immersion brewing quite a lot.
And in recent videos, they've been times
where immersion brews have been under extracted
but it still tasted pretty good.
So here's the really simple experiment.
I'm gonna take a stock and quite common grinder.
In this case, I have an EK 43 and I'm gonna set it
at five different grind settings
going from its coarsest setting all the way through
to its very finest setting.
We're then gonna take those five grind settings
and brew a cup of coffee
with each of these two methods with them.
And at the end of that
we'll do some extraction measurement.
We'll see if one brew method performs better than another
but more importantly at the end of all of that
when they've cooled down, I'll do a big taste test.
I'll line them up and I'll do a head-to-head
at each ground setting to see which one comes out on top.
I will acknowledge now that that taste test
will not be a blind test
'cause I don't have anyone here to help me with that
because of the way things are at the moment.
But I still think it will be interesting
for me to taste a comparison and go side by side.
So let's begin.
We're gonna grind 20 grams of coffee for each brew.
I don't think we need to brew much more than that
but brewing less than that
I don't think necessarily would be fair or real world.
To try and give you a little bit more insight.
Here are the five different grind settings
showed next to the KRUVE brewler,
so the way it's gonna work is this,
I'm gonna brew a French press using my
French press technique that I'm very fond of.
You can check a video up here,
if you wanna see how to do that
let it steep for four minutes.
I'm gonna break the crust, scoop it off.
And then I'm gonna pour relatively quickly after that
because I'm not worried about sediment
in this particular case, I'm worried about extraction.
And later on, I'll obviously remove any sediment
or suspended material from a sample that I'll do
an extraction test with using a refractometer.
As this deeps I'm gonna brew myself and I settled V 60.
All alright, first round done, four to go.
Okay 10 cups of coffee have been brewed.
It took a reasonably long time
but we're done, we're through it.
It was kind of interesting
everything at the coarser end of things,
which is here the coarsest
through to here at the finest brew very quickly
as you'd expect.
In the middle it kind of brewed quite normally
at that sort of eight setting
close to where I would be anyway.
The moment we got to four
things got muddy and soupy and weird.
And by the time we were one
that pour over looked super odd,
it looked like there was some
sort of channel potentially there.
I don't really understand what I was seeing
in that bed at the end of that, but it didn't look good.
Now my original plan was to do the extraction measurements
on these first, but I think I'm gonna taste them.
I think I'm gonna taste them first to have as little bias
as possible going in
because I'm gonna have a bias
knowing which one is which on each case.
Now for you, the ones at the front here
are the immersion brews
and the ones at the back here
are all of the percolation brews.
Let's start at the coarsest end with these ones.
I'll spare you the endless slipping noises
having had a slurp, it's kind of interesting.
So here at the very coarse end
they're both obviously quite empty,
quite hollow, quite weak.
There's a slight kind of tanginess
a slightly less pleasant acidity
in the percolation and the poor over brew,
than the immersion.
Moving up just a little bit.
There is definitely more textures of both of them.
They do taste a bit stronger in both cases.
The immersion brew does just taste a little bit sweeter.
I don't know how else to describe it.
Into the middle which is actually kind of
where I'd probably grind for both of them.
So I would expect peak quality here.
Yeah, both are very pleasant, both very enjoyable here.
They both have good qualities.
The clarity that you get from paper filter is pleasant
that extra texture here and kind of richness
is also very pleasant.
Going finer again though we see a big change.
In both cases there's a slightly roastier characteristic
to this coffee.
This coffee is, I don't know it very well
but it's sort of in the sort of medium range of things,
I guess, for a filter coffee.
So that roastiness it's kind of there for both of them.
The difference is that the percolation brew
the pour over has a pronounced kind of
bitter attack to it that the immersion brew does not have.
So there's a harshness and an astringency
and a bitterness to this percolation brew
that just tastes a lot less pleasant.
It tastes ultimately
like a much less even extraction at this point.
And that's probably because
we're starting to get some channels forming
in that percolation brew.
Things are starting to fall apart
and then you get to that very fine setting.
The coffee's lost a lot of its fruit here
as an immersion brew.
But again, it's not overly bitter.
It's not particularly harsh.
It's quite muddy.
It's difficult to discern flavor
but it's not unpleasant at all.
It's really not that bad.
The pour over though, very harsh, very bitter,
no sweeteners, just really a lot less enjoyable.
So every at the beginning I'm gonna call that one a draw,
neither is victorious, particularly.
Here, I don't really like to call it
but I'd probably say maybe the immersion
but it's pretty close.
Here in the middle like for like I could not pick a winner.
And then here by this point
the immersion has pulled ahead, right?
The immersion brew is notably more delicious
than the percolation brew.
And at the end here with that very fine grind,
massive win to immersion brewing.
The percolation is extremely unpleasant to drink.
It is undrinkable, but I could drink.
I wouldn't necessarily enjoy it
but I could drink that immersion brew.
So we'll do some actual measurement in a moment.
Where we'll measure those extractions
and see how they chart out compared to what I tasted.
And then we'll also talk about
what the real world implications of that might be.
How does this experiment matter to you in the real world?
And then we'll talk about why it might be this way.
Why would immersion have this advantage over percolation?
Why might it in these particular circumstances
be a better brewing method?
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So the measurement is done.
All 10 samples have been measured.
There were all stirred before a measurement was taken.
And those that were from the French press
were filtered again through paper
to make sure that there was no suspended material
to mess up our results.
Now what's important about refractometer numbers
is not to take them as absolutes.
There are a number of other factors here
that I don't really wanna get into.
What we can look at, what is valuable are trends.
With the immersion brews most of those numbers
are in the kind of good extraction zone.
Again, I don't wanna get too much into that
but the way that they increase seems to make sense.
The finer you grind
the more extraction you see with an immersion brew
and that's reasonably linear, not entirely but reasonably.
And it sort of starts to top out
as we get towards the threshold
of what is easily extracted from coffee
with the V 60 something very interesting happens.
We see that increase in extraction each time
and then suddenly it seems to plateau
and then it falls back.
And at the finest grind setting
we saw the lowest extraction.
What on earth is going on there?
Surely that defies convention,
but actually this is a phenomenon
you see all the time in espresso.
When you go to fine, you get channeling.
Generally speaking if water can find
a path of less resistance, a channel
then more of that water will flow
through that part of the bed.
The coffee around that channel will have a lot of extraction
because most of the water has flowed through it.
And the rest of the coffee won't see as much extraction
which is why on the whole, the bed is under extracted
even though the taste was extremely bitter and unpleasant.
And so it would be a fair argument
to say across grind sizes,
immersion brewing does a better job
because it does, it does a better job
because all of the coffee spent a good amount of time
in contact with all of the brew water.
With percolation the brew time is quite variable
and it's determined by the size of the grind
for the most part.
Now, when it comes to coffee theory and extraction theory
it's important to understand
that very little water penetrates
into the grind of the coffee.
Mostly it's washing away what is on the surface
of those grounds.
That means your limit for extraction
is set by your surface area.
Immersion has the advantage
of having all the time that you give it
to do that extraction
to whatever surface area is available.
With percolation your contact time is determined
by the grand size, by the resistance
it gives to the water as it floats through.
And so with a coarse grind
your water doesn't get much contact time.
And that's why it produces such inferior results.
Typically, compared to immersion brewing.
As you go finer it does get better.
And we see that in terms of taste
but then you hit a wall of fineness
where you've gone to fine
and the water is looking for channels,
finding them, exploding them
and your extraction goes down
and your taste gets much, much, much worse.
But what does this all mean for the real world?
Well, one, it doesn't mean
you should stop brewing with percolation brewers
and only use immersion brewers.
That's ridiculous.
You can get incredible cups of coffee
from percolation brewing.
I love pour overs.
I think they are delicious.
This is not what I'm saying.
If you are stuck with a grind
that is not suited for your pour over method though
brewing it with an immersion brew
is likely to yield you better results.
And this I think also explained
the enduring popularity of something like the AeroPress.
the AeroPress combines immersion brewing with percolation.
You have this sort of steeping phase typically
followed by some percolation.
And I think giving a decent amount of time.
And I generally prefer longer steeps in an AeroPress.
I think for this reason,
means that you're likely to have a pretty good infusion
a pretty good immersion brew
before you then go through an additional percolation phase.
But the AeroPress is something we'll talk about
another time.
But now I wanna hear from you.
I hope this is gonna be a useful little tip,
a little trick, a little hack to have in the tool bag.
Should you end up with coffee ground
in a way that you don't want it should be ground.
What should I have tested?
What didn't we test?
What should we look at in the future in these kinds of tests
and experiments?
I would love to hear from you down in the comments below
but for now, I'll say thank you so much for watching
and I hope you have a great day.