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This was also discussed on HN a few days ago.[1]

[1]: https://news.ycombinator.com/item?id=48552440

I guess that might explain why they had it at such a low temperature (way to low I'd say), as they wanted to make a point about the lower energy consumption? If you wanted it hotter, then it might not actually save energy at all potentially?
This seems very interesting, at least from a pure coffee nerd standpoint and what it could mean for improving espresso brewing in general.

However, I'm going through the research paper, and am a bit skeptical of the energy savings angle, especially considering the many variables with espresso machine in terms of how they heat and brew (single vs dual boilers, heat exchangers vs dippers, spring lever machines vs pump driven). I'm weary of how they are doing a baseline comparison here, especially because the paper states that the comparison was done between a modified Ascaso machine (with the ultrasound gizmo) vs an entirely different machine (Sanremo Cube); and also that they swapped the Ascaso machine's original brew pump and put in a seemingly expensive, but more efficient "positive displacement magnetic gear pump". They still use the pump to drive about 11 bar of pressure during brewing with it run on some sort of interval schedule throughout the 3 minute cycle. They did factor out the initial heat up times which I guess makes sense.

However, another thing (on top of the obvious "room temperature espresso" problem) is that you'd still need steam / heat to produce milk based drinks (relevant for both home and especially cafes). Depending on the machine (including the Sanremo Cube they tested with) some of the "idle energy" usage is to support on demand steam generation. This doesn't seem to have been factored into their energy model which is pretty sketchy.

"room temperature espresso" was the first thing I thought of - espresso is meant to be drunk hot, right away. If you let a good shot cool off and compare it to a bad shot you're not going to notice the difference as much because you made them both worse by letting them sit and cool.

For industrial processes it probably doesn't matter - look at how nescafe is manufactured.

Ok, I just looked it up and the Ascaso Uno is a thermoblock design, while the Sanremo Cube is an HX machine with a full on steam boiler. Therefore, the Ascaso wouldn't even have instant on steaming and has basically no stand-by power usage. So yea... their comparison is bogus, unless I'm missing something from the paper.
It seems like most of the energy associated with espresso would not come from the brewing step, but rather from the cultivation, processing, and transportation of the beans. Similarly, the brewing energy is likely 100% electrified, and could be supplied by carbon neutral sources, while the energy from earlier in the process is more likely to be from fossil fuels.
Room temperature espresso is very intriguing to me. One of my coffee complaints is the heat involved.
"Wary," not "weary." I try to suppress my pedantic urges online, but wary is a great word and it gets misused a lot! I hope the feedback is helpful and not annoying.
Very interesting for industrial use, that’s for sure.

For domestic use, in the home of somebody whose coffee snobbery is dialled to 11, I need far more information.

What beans were they using, freshness, etc? (Edit: Campos coffee… not on my shopping list that’s for sure…)

How did they control for extraction method differences to maximise output quality for all brew methods? (Edit: TDS and EY)

Were the “regular” coffee drinkers regular consumers of espresso?

Most importantly, how long until Hoffman does a deep dive and much will it cost so I can allocate budget for yet another coffee making device?

> Campos coffee… not on my shopping list that’s for sure

I’m from Melbourne, have a Brewtus IV + Mazza Mini, probably have a low user ID on coffeesnobs, hung out every day our Prouds and Patricia’s, and can tell from first sip if the beans are South American, African, or from Sumatra, so you can probably tell I’m anal about my coffee… and all I can say is don’t knock Campos (especially their King Street).

> Did the espresso drinks have milk in them?

I felt a great disturbance in Italy, as if millions of voices suddenly cried out in terror and were suddenly silenced.

Espresso does not have milk.

Macchiato, is an espresso based drink with milk.

Edit: it's bad form to change your message after-the-fact to remove the thing that was quoted.

My dad was stationed on a submarine in the navy and he and a few others used to dump their laundry in the ultra-sonic cleaner normally used to clean engine parts. Said it did a great job....
Submarines didn’t always have laundry services. For a 90-day trip, the crew would bring six uniforms and rotate them daily. Shower was one minute of water once a week. Everyone smoked tobacco all the time, everywhere.
Maybe there can be an ultra-sonic laundry machine
After the last one of these posts talking about cold brew coffee I attempted to replicate the results by just throwing some water and coffee into an ultrasonic jewelry cleaner. Results were not satisfactory. I wonder if extracting the transducer from the jewelry cleaner and attaching it to my Portafilter would work.
It'd be a learning experience to find the right settings.

Coffee usually goes in two directions. Under-extracted (sour) or over-extracted (bitter). Things that will affect the extraction are temperature (hotter usually means more extraction), time (longer = more), grind size (more surface area in smaller grinds = more), pressure (higher = more) etc. Roast levels also matter.

"Most of us think of espresso as a hot, high-pressure ritual." - No, most of us dont care how the sausage is made, and just want the end product. Sure theres lots of individual coffee enthusiasts who cares, but in % terms thats not "most of us", most of us do not care, and nobody in my 40 years of life has ever complained about coffee energy usage.

Extract with sound waves is an interesting idea, but dont romanticize demand that doesnt exist, it wrecks credibility, literally in the first sentence of the article

An espresso machine is essentially a 1-2kW electric boiler, a compressor pump, some valves/actuators, and some PIDs, right?

Even if it draws 1.5kW constant for 24h/day that’s only 36kWh. That’s about ~$5 to ~$15 of electricity, depending on how mismanaged your utility is.

It costs less than an hour of labor to power an espresso machine for an entire day, the energy cost to pull a shot is negligible, pennies. The rooftop unit cooling and heating the coffee shop probably uses 2-3x more energy.

A very similar process does a lot more than just coffee

https://www.youtube.com/watch?v=YlQT4ptwLKs

I was inspired by the above video and have been playing around with ultrasonically aged drinks for quite some time now. It's quite fun. Still haven't brought myself to try ultrasonically aged milk yet though.

About 6-7 years ago I bought a machine that prepares single-shot cold brew with ultrasonic cavitation. I like my caffeine potent and chilled, so this has worked out extremely well for me.

When I have a guest that wants a hot coffee, I just pour the shot into a mug and top it up with hot water to their taste, which works great.

What this isn't is anything new. That doesn't make it bad, but it's not novel.

As I glance at my (checks notes) $200 power bill in San Diego apartment used entirely to run 3 ceiling fans and a box fan, I’m getting curious about all the ways power consumption can be reduced. No AC, LED lights, all gas appliances.

I am going to switch over to a bunch of DC tower fans which claim to cut energy usage substantially. I wish more appliances would just switch to DC motors.

This is fascinating from a food technology standpoint.

But the framing of the article around espresso specifically is somewhat bizarre. Most people want their shot of espresso to be piping hot, not room temperature. And most iced coffee is very intentionally not made with espresso (although you certainly can use it if you want).

The text of the article seems to suggest that this is more intended for "making ready-to-drink coffee products at industrial scale". But then that is not single-serve espresso shots that the article shows in several images.

So is this about room-temperature espresso shots (not what most people want) or about industrial-scale concentrated coffee? And if it's the latter, what would those machines look like? It's one thing to use ultrasound at a small scale; but what about in gigantic basins? Does that work, or are there challenges? Is this tech that scales?

I've noticed a lot of people lend the name espresso to things that obviously aren't espresso. Is there any reason for this?

I get the sense that these people think calling something espresso is a mark of quality, but it's just a brewing method like any other...

At a 3 minute shot, I’d rather use the same time to do a pour over
I see the value for American-style "espresso-flavored" drinks, or similar bottled/packaged products.

But, yuck, who on earth wants to drink actual espresso at room temperature?

I don't really care about the very small energy savings, but I'm excited about smaller espresso machines:

- The taste is apparently the same "There were no significant differences in aroma, flavour, bitterness or overall liking."

- That ultrasonic horn looks a lot smaller than both a modern espresso machine or a hand-cranked model like a Flair/Rok.

I tend to wake up before my partner, and I can only imagine the look on her face when the ritualistic grinder noise gets joined by a noisy brewer.

In all seriousness, people tend to have a routine around coffee, but I think the Aeropress showed that people will change if the result is meaningfully better.

Yeah, if I drink an espresso and it's not hot, I'm fighting the barista.
I don't know anyone who buys ready-to-drink coffee all that often. It's more of an impulse or convenience buy.

Cutting costs does make sense for this type of product, but is it enough to keep up with declining demand?

> [...] that produces high-frequency high-frequency transducer attached t. Richard Freeman / UNSW.

AI generated/hallucinated article? Or no one, author or editor, read it before publishing?

The guy is from Colombia, so I can believe it is a good method
Can’t wait for the ultrasonic truck driving my coffee beans down the mountain to port, and the ultrasonic cargo ship bring my coffee beans from Colombia.
If you want to really save energy, then they've already made the ideal product: caffeine pills. It's all the wonderful drugs without any of the bullshit. You can have it at any temperature, with any drink or even without a drink at all. It doesn't get cold or give you coffee breath. They're ultra compact and don't require rituals or specialty restaurants. They're also incredibly cheap.
Is power consumption really the issue. Or just more consistent flavor?
I want to meet the person that CAN distinguish between the espresso
Cool, but does it taste like the one made by Bialetti Moka Express?
What's the cost for the machine though?
Can it do Black? :devilhorns:

I like my coffee heavy metal.

see also sonochemistry https://www.organic-chemistry.org/topics/sonochemistry.shtm
Manual lever machines like the Flair use even less energy. This is silly.
Don't show this to the EU, or they will force us drink only ultrasound espresso from now on.