Making espresso with ultrasound
unsw.edu.au
unsw.edu.au
> It is noted that espresso is normally consumed hot and has transient sensory attributes that are temperature- and time-dependent. Hence, serving espresso at 22 °C will alter its sensory characteristics.
This is a weird test, coffee get’s so much worse when cold. So people can’t distinguish between two bad coffees.
Coldbrew is a thing and done right it brings out a refreshing sweetness. Also iced coffee. Bad coffee is bad hot or cold.
I would rather have room temperature coffee than a cold brew usually though. I just did not have good luck with it so far
This is a myth. Bad coffee tastes better when hot because your sense of taste is dulled - reducing bitterness. Also, at higher temperatures, aromatics and volatile compounds are more airborne, improving the smell of coffee. Good coffee is better enjoyed around 60-70C
Regardless, I would say it’s an objective fact that good coffee is ruined at room temperature. It still tastes fine, but no where near as good.
What especially irks me is that they could have just heated the stuff in a microwave [1] to 50°C and have a much better test.
If you want to scald your mouth I don't think you need coffee to do that.
Room temperature coffe is just like room temperature water: boring.
Our espresso machine (De'Longhi) makes cold brew in like a minute or two. Brilliant. It's tastes like normal cold brew but I enjoy espresso over ice better. Maybe this ultrasonic espresso machine could achieve better extraction with cold water than purely pumping water at high pressure through coffee?
Anyway I'd be quite excited to see a review by James Hoffmann when it hits the market.
How does ultrasound affect flow rate? Do fines sink to the bottom of the puck and choke the shot?
There is a new movement happening, especially in lighter roast coffees, where we're finding that more balanced extractions (less bitterness/acidity/acridity) are happening at lower pressures, even going so far as grinding so coarse that the puck offers zero resistance - effectively making the pump the limiting factor for flow rate. Light roast coffee is much less porous and more hydrophobic.
I wonder if adding ultrasound would allow light roasts to yield more extraction in general, maybe even keeping the high temperature. Or, would adding ultrasound allow a finer grind size and more resistance without adding the harsh flavors of a high-temperature shot.
So many experiments to be done!
Edit: The article shows that they chose this method specifically to use the basket, and the basket allows for the vibrations they need. The other conveniences of the basket form factor also come into play; reloading, cleaning, etc. and don't need reinventing or retraining. Cool stuff. I wonder whether they'll remodel the machine around the basket and remove what's not needed if this becomes a product.
Where's James Hoffmann when you need him?
[1]: https://www.unsw.edu.au/newsroom/news/2024/05/Ultrasonic_col...
(You might quibble whether it's actually espresso if there's not pressure and it's extracted cold; but it's closer to espresso in strength.)
I like the ritual of it, for sure, but I'm not sure that's what makes it a good shot?
I'm surprised by this, my assumption from hot coffee vs cold brew was that since the water isn't hot, there wouldn't be as much bitterness? Or maybe I'm reading it wrong and it's why they prefer it, because it's less bitter?
Makes nice coffee, but I don’t think it’s worth the cost (but he has a lot of money, so it’s not a big deal for him).
I envision some fairly high-end kit, coming from this.
An awful lot of people drink iced espresso drinks these days. Room temperature (or below) brewing would make a big difference to the dilution in those drinks.
Might be a new meta for iced lattes.
It's not for you
There's a semi-famous, super hipster cafe near me in Tokyo, that I sometimes go to.
Once, they had a special on the menu, when they give you a flat white, and a double shot of espresso on the side, with a thermometer hovering over the shot, with suggestions of tasting notes that you can get out from sips at different temperatures.
Now, that's generally very much a thing — things definitely taste differently based on the temperature (or maybe _they_ don't, but we _perceive_ them differently? distinction without a difference, I guess.).
The suggested temperature ranges were 51-40C; 40-30C, and 30-20C.
51-40 was great. 40-30 was getting weird, but still _interesting_, because you definitely got different notes.
But the 30-20 was terrible. That is absolutely too cool to enjoy a shot of espresso. I'm all for experimentation and doing weird things, but that was no longer riding the line of "not great but interesting" and went straight into "why would you ever do this" territory.
A typical recipe is something like 20g coffee and 80g water, yielding about 60g of concentrated coffee. Lance Hedrick has done a few videos on the subject.
It is not espresso, obviously, but it takes no time to prepare, it tastes fantastic and it is very easy to dial-in.
Still, pretty cool.
TL;DR: Aiming for a high-volume industrial goal, tone-deaf to coffee enthusiasts.
But perhaps this can be used in the instant coffee industry or something.
But I also need my coffee: I'll drink whatever quality coffee is being offered, as long as it's the best I can get that morning.
Technically you can also buy a bottle of grape juice from the grocery store, let it sit on the kitchen sink with a yeast lock for a few weeks and call it wine, and technically it even is, but it's also going to taste quite shitty.
You could just read the linked paper?
> Esp was prepared using a Sanremo Cube espresso machine. Brewing parameters were standardised following the supplier's guidelines: extraction time of 35 ± 3 s, pressure of 9 bar, and boiler temperature of 122 °C, with the corresponding group-head temperature of 94 ± 1 °C. A total of 21 g of ground coffee (GS = 2.6 ± 0.1; ∼262 μm) was placed in a ridged coffee basket and tamped using a constant-pressure tamper (MHW Flash Constant Pressure Tamper 2), applying 13.6 kg of force. The BR was reduced from 2 to 1.7 following the recommendations of the coffee roaster for better flavour (1 g of coffee grounds yielding 1.7 g of coffee brew).
1:1.7 is a bit short for my preferences (I like longer shots, usually aim for ~2.5); but otherwise that sure sounds like a pretty good double to me!
As stated in the article, the whole point is for use in ready-to-drink coffee manufacturing.
Cold drip coffee is a thing, done well a very nice thing.
An average coffee shop's espresso machine might use $200/month of electricity, so even though the percent saving (75%) is high, it's off a base that's small relative to other costs; possibly too small to be enticing.
If you're drinking light, floral and acidic coffees, it's been relatively "trendy" recently to skim the crema off before drinking it.
I don't bother with that, but pulling two shots and removing the crema from one of them and trying them side by side is an interesting sensory experience — I'd encourage you to try, at least once!
https://www.vice.com/en/article/a-vietnamese-company-is-brin...
Seemingly as early as 2010:
https://en.wikipedia.org/wiki/Trung_Nguy%C3%AAn#Weasel_and_L...
I assume that such coffee is good because the civet cat has taste for good coffee cherries, not really because of the digestive enzymes or whatnot.