- Today, we're gonna be doing some grownup coffee science
and some weird coffee science,
because finally I've got my hands on some liquid nitrogen,
kind of as much as I want,
'cause I'm here at Cometeer and here at Cometeer,
they have a lot of liquid nitrogen.
I think I just need to show you how much they have.
They have this tank of liquid nitrogen
outside of the building.
This thing is huge. It's like three stories tall.
It is just massive.
Now, if you're unfamiliar with Cometeer,
they buy delicious coffees, extract them,
and flash freeze them, so all you have to do
is melt that back into hot water
to have a delicious cup of coffee,
which means they've got lots of liquid nitrogen
and so we're gonna be replicating, to start with,
the experiments of Chris Hendon.
Now, before we continue,
there's a couple of disclosures I should make.
I'm here at Cometeer because they're extracting
and I'm gonna taste some Square Mile's coffee
to go into the capsules.
And secondly, I do have an ongoing relationship
with Cometeer, which means that you should absolutely
treat this video as an ad.
Chris Hendon wrote a paper,
he was the lead author on a paper in 2015,
that basically convinced everyone
that grinding frozen coffee beans was better.
His research showed that the colder the coffee was,
the more uniform the particle size,
and also the finer the coffee ground.
Now I'm not saying the science is wrong,
I just want to check, I just want to repeat it.
So the first thing we're gonna do
is kind of replicate that thing,
but let's get into the science.
For that, we need some liquid nitrogen.
(liquid sizzles)
So what we're gonna do, and I know I look good,
but what we're gonna do is take 10 grams of coffee,
poach it in liquid nitrogen,
and then throw it straight into the grinder.
We're gonna then take some frozen coffee from the freezer,
grind it at the same grind setting,
and then we'll take some room temperature coffee,
grind at the same grind setting,
and then we're gonna compare the grinds of each of those.
(metal plinks) (liquid hisses)
(grinder whirs)
So what I now have is 10 grams of room temperature coffee,
freezer coffee, like domestic freezer,
like -15 and -20 degrees Celsius,
and then the liquid nitrogen coffee here.
Now we could brew them, but I want to go deeper.
There's toys here that we can play with,
so we're gonna take these to a particle size analyzer
and actually look at the difference
between the grind distributions of these three coffees.
Let's go do that.
- This is a laser particle analyzer,
and it tracks the distribution curve of our grounds
that we'll be sampling today.
We load our grounds into this over here,
and when we close this, a vacuum will suck up
all the grounds into this analyzer over here
and it'll take readings and show a distribution curve
on the screen over here.
- We have our results.
Now, what Hendon's papers suggested was that
the colder you make the coffee beans before grinding,
the finer the grinds would be
and the more uniform the particle size would be.
Did we get that result?
Well, kind of, actually.
What was interesting to me is that
the room temperature coffee was really very similar
to the kind of domestic freezer temperature.
The kind of average particle size
or the kind of peak particle size
went from 670 microns down to, like, 664,
which is a pretty minimal change, to say the least,
and sort of surface area didn't change that much.
But we did see a bigger change with the liquid nitrogen.
That dropped down to 640, but when you look at the data,
what you'll see is a real change in uniformity
and in surface area as well, so it's definitely true.
The colder you make the coffee, the finer its grinds,
and sort of the more uniform it is.
So we wanna do a taste test to kind of understand
this whole thing a little bit more.
So here's how it's gonna work.
We're gonna brew three cups of each
of the three temperatures of beans.
So we'll brew a room temperature, we'll brew a freezer,
and then we'll brew the liquid nitrogen-chilled beans again.
To match the grind settings is tricky,
and we've used the particle analyzer again
to try and dial it in.
So the difference is this.
To get a matching particle size,
if we grow the liquid nitrogen, frozen beans,
at 6.5 on the EK, we're gonna be grinding
the other two at 6, so like a half step finer
to try and match the same sort of peaks
as that super chilled frozen coffee bean result that we get.
So we've brewed the three brews.
Michael's mixed them up again for me,
so I don't know which is which, which is interesting.
The room temperature and the frozen
brewed pretty identically in terms of drawdown time.
The liquid nitrogen brew was actually very slightly slower,
but not so much slower that it couldn't have been my fault
for being slightly inconsistent.
There was a maybe 10 second slower than the others.
I wouldn't say it's super important or worth worrying about.
I think, ultimately, these brewed very similarly.
Can I detect a difference in taste?
I may not be able to, but we'll see.
This cup is, like, a little bit sweeter and cleaner.
It's almost lighter, right?
And that could be me having a little confirmation bias
in that I think it might be the liquid nitrogen
and therefore I think it might have a few less finds.
I need to taste these some more.
There's like a little extra harshness in these two cups
that isn't as present in this one.
It's kind of weird, it's a weird thing,
because this one tastes almost less extracted.
I feel like actually I would want to go find out
on this one, whichever it is.
It doesn't taste as extracted as these two,
but it tastes lighter and cleaner
and kind of more, kind of linear in a way,
not in a bad way, but just, like, less attack on it.
If I'm honest, I'm gonna pick this
as I think this is the most uniform particle size,
therefore I think it's the liquid nitrogen.
These two, interestingly, and I expected a bigger difference
between the freezer and the room temp,
but actually, maybe I shouldn't.
If we think about the data that we had before,
they were surprisingly close in terms
of particle distribution and kind of peak particle size.
So these two, I think,
are very similar in that way.
I don't know which is which, so that's my guess.
I guess we try and do a reveal and find out.
This is B, therefore that's the freezer one there.
This one says A.
Good, that's A, so that is the room temperature.
So that kinda makes sense.
And this one, I'm gonna lift it up,
even though I know what it says.
That is the C, okay. What does this mean?
'Cause that's ultimately the question.
Why run this experiment again? What are we trying to learn?
How does this apply to you at home?
I'm not saying you have to go and get a Dewar
and get some liquid nitrogen and start freezing
your coffee beans before you grind them,
even though it's quite cool and huge fun.
What I am saying is that I had previously been
not a huge lover of grinding from frozen,
but I think I've had that opinion challenged
quite heavily here.
I think there's no real downside to grinding from frozen.
You know, we didn't see a big difference
in particle distribution.
I don't see a big difference in taste when you brew them.
And that means if you like to freeze coffee
to keep it longterm, 'cause freezers are super helpful
for that, then you don't have to worry about defrosting
or that kind of stuff.
You know, I think there can be differences
that are more pronounced with something like espresso,
where small, small variances in particle size
manifest in flow rate quite notably, but for brewed coffee,
I think grinding from frozen is definitely okay.
It's definitely good thing.
And I think the liquid nitrogen is just cool,
And I kinda want to breW that again a little finer,
but that's the learning here.
The paper was right. I agree.
We've replicated Chris Hendon's work.
That's what we got, and we learned a thing.
I'm very grateful for Cometeer for hosting me here
and indulging me in my ridiculousness.
If you want to check out what they're doing,
there's a link in the description down below.
It's not an affiliate link,
but you should totally treat it like an affiliate link.
You can check it out if you want to.
But now I want to hear from you.
Have you done an experiment like this?
Have you tried to do a side-by-side
with freezing coffee or brewing at room temperature?
Did this go as you expected?
Have you seen anyone else kind of replicate
this sort of stuff with the liquid nitrogen?
But for now, I'll say thank you so much for watching
and I hope you have a great day.