Welcome to today's episode of Weird Coffee Science.
Now, usually these are designed in a way
that you can replicate the experiments at home.
This is not the case this time.
This one, you need some lab grade equipment.
Now I'm regretful.
My friend, Bill, happens to have in his kitchen
a lab centrifuge,
for many good reasons that involve delicious cocktails,
but he has kindly lent the centrifuge to me for today.
So I'm gonna get appropriately attired
to do some proper science.
And now, lab coat on, I'm of course perfectly dressed
to make some espresso
which is what we're gonna start with.
So here's the thing,
here's the thing that I'm interested in today.
We talk a lot about the oils in espresso,
about how good they're,
about how wonderful they are,
about how that's one of the best bits of espresso.
But I'm curious what the oils
on their own are actually like.
So here's what we're gonna do.
I'm gonna make a bunch of espresso.
We're then gonna put that into these little things
and put them inside the centrifuge.
This will then separate the oil from the liquid,
from the solids that are suspended in the espresso as well.
And I will have a little taste
of both of those things and see what we see.
So to do that, I'm gonna need to make some espresso
which is what I'm gonna get on with now.
So in this jug, I now have a hundred grams,
a little bit more actually of espresso.
I'm not too worried about crema or anything like that.
That's just foam, that's just gas trapped in coffee
that can go away.
That's not the important bit.
So we've got lots of good espresso.
So now we have to put it into the centrifuge.
And to do that, we have to wear it very carefully.
They really have to be the same weight,
the two kind of buckets
that face each other inside the rotor.
If they're out of rack, the whole thing is very dangerous.
It'll be kind of unstable.
So they've got to weigh the same
to within at least a 0.1 of a gram.
So now it's time to load the machine.
We're just gonna put two in,
you can run up to four,
but we're just gonna do two this time.
So these are now ready to spin.
So this first time we're gonna run it for about 15 minutes
to see what we get.
Around and around we go.
So this will get up to about four,
four and a half thousand RPM, maybe.
We'll let that run for 15 minutes.
so we're done, it's spinning down.
It's gonna eventually stop.
Then we can take out a tube,
and see what we can see.
That's Ooh, interesting.
Got some solids at the bottom here.
And there's just a very thin layer here at the top of oil
which is exactly what we wanted.
Oh wow, it's actually semi solidified.
Like it's acting like a little floating cap of fat
on top of the shot, it's a little girl.
This is kind of gross.
It's like a gooey, almost gelatinous fatty layer.
So there's really only one thing left to do, for science
and that's to eat this, drink this, feed this.
It feels like eat as I look at this right now.
I can't pretend to be appetized.
But hey, coffee oil in espresso.
It's the best.
Oh no!
That's very bad.
That might actually make me cry.
That is,
that is incredibly bitter.
There were obviously a lot of very
oil soluble, bitter compounds.
And now I have a kind of greasy, bitter mouth.
Don't say it.
I should try the liquid underneath.
Maybe that's better without the oil.
I don't know.
You mean it's like a paper filter to espresso but not.
What is wrong with me?
No, no, it's like a, it's fine.
Much better than, oh, the oil.
I still have a lot of bitterness in my mouth.
And I feel like there's definitely been some degradation
of the espresso in the last 15 minutes.
It's cold, which sort of amps up bitterness as well.
But otherwise it's quite a nice shot.
The liquid underneath is fine.
That is not a ringing endorsement
for the oils present in espresso.
They don't make the crema.
We'll have to discuss crema in depth one day,
but oils don't make a crema.
Oils cause problems with crema, actually.
They certainly add texture to an espresso,
but they also are bringing some interestingly
negative flavors that was they're dispersed
out into the rest of these espresso, they're okay.
But on their own.
No, not good, not good.
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So here's experiment two.
What happens if you clarify
or separate grounds from water with a centrifuge?
Now this is my idea.
A gentleman called Yohanas had emailed me,
saying he had access to a lab grade centrifuge
and he wanted to know what would happen.
What kind of ratios to use
to sort of steep ground coffee and water together
and then spin to separate.
Because in that last brew,
all the solids got pushed to the bottom.
So what if that's something we can do
to sort of make a nice brew?
Here's how it's gonna work.
I've got some coffee, I'm gonna grind it.
And then I'm gonna take about two grams,
add it to each one of the tubes inside the buckets.
I'm gonna add about 30 grams of water,
seal it up, give it a quick shake
and then get it in the centrifuge.
That should give it long enough
at a very fine grind to steep and infuse,
but then very quickly be separated.
And when it's separated, it should stop extracting.
So this is espresso grind.
It's the same grind set we used to pull shots a minute ago.
'Cause I think we're gonna have a pretty short brew time
if these are going straight in.
261.24, so point four, acceptable.
Okay, it's a little slower to get sorted than I had hoped.
This should not be good.
Let's just try it for five minutes, five minutes.
Actually, maybe let's just get it up to speed
and then slow it down again,
and see if it's even separated at that point.
Oh yeah.
I mean that is very, very separated.
A little bit of our friend, the coffee oil on top.
Not what I was hoping for.
Not too much coffee oil, which nice.
It smells good.
Cheers!
I mean, this is crystal clear.
That was pretty good.
It was pretty good.
I mean, it's actually a little weak,
a little under extracted ironically,
but that is a very clear liquid.
All right, I have to do this again
with, I think a longer brew time or a bit more agitation.
And then I think we're onto something.
We're just gonna run this again very quickly.
I felt that that previous version
was a little under extracted.
So I'm gonna add my hot water,
make sure that the buckets were exactly the same,
but then give the tubes a little shake
and then get them straight into centrifuge
and spinning, spinning, spinning to do that incredible job
of separating the grounds and the liquid.
Let's go.
Have they separated?
Oh, Ooh.
I feel a little bits of something floating in there.
Looks good.
It smells good.
That agitation has definitely helped increase our extraction
right up to the limit.
Actually that tastes very well extracted.
The first one, not as much.
This, yes.
But it's good, it's clean.
Like blindfolded, I would have no idea
this hadn't been through a paper filter.
Now that's interesting just to have a quick look at the TDS
and the extraction approximately.
We're pretty high extraction on that.
It's showing something like a 23 and a half 24% extraction,
which is high.
Typically it's really, really hard to do infusion brewing
with very finely ground coffee
because they don't separate very easily.
The one, I guess, counter to this is kind of brick brewing,
which does that but they don't really separate the same way
and you end up with a very differently textured beverage.
This didn't taste as intense and strong as it is
because it was so clean.
That's interesting.
Let's summarize what we've learned from today.
We talk up oils and espresso a lot,
but on their own oils and espresso are very bad, very bad.
And we should think about that
and maybe not lavish them with praise
as if they're the most important aspect of the beverage.
That was interesting for sure.
As for the idea of using a centrifuge
as a way to separate grounds and water,
as a kind of filtration method.
Definitely interesting because you can easily separate
very, very, very finely ground coffee from water
in a way that it's usually hard to do.
Paper filters don't work, they clog.
It's hard to get them through things like
espresso machine baskets.
You need huge amounts of pressure.
Here, we did it a different way.
And the result was very, very, very clean.
It was very interesting.
It tasted good.
Undoubtedly, it tasted good.
But that's not really a practical thing, is it?
I mean, it's fussy.
It's hard to make sure that your buckets are balanced.
It's not easy, but it was interesting.
I hope you found it interesting too.
Now let me know down in the comments below
if there's any more stuff
you want me to put through a centrifuge.
I've got this for a little bit longer, so be quick.
I might do it if there's a really great idea.
Have you tried something like this?
Did this confound your expectations a little bit?
Let me know in the comments below.
As always, thank you so much for watching
and I hope you have a great day.