I used sound waves to make espresso | Hacker News Reader

I used sound waves to make espresso

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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?

Probably best suited for cold drinks where the heat is just purely wasted against the ice and diluting the drink.

The heat isn't wasted, it has a significant impact on flavor.

Extraction of flavor etc from coffee grounds changes based on the water temperature. You can easily experiment with this by taking some coffee grounds and trying to brew with various temperatures, and noticing what flavors you get out.

There's a reason cold-brew needs hours and hours to extract a good coffee flavor while regular espresso or pourover is done in a matter of minutes.

> For the espresso samples, participants could not reliably tell the traditional and ultrasonic versions apart. There were no significant differences in aroma, flavour, bitterness or overall liking.

Yeah, I don’t buy it. Just because you make some claims and say it was scientific doesn’t make it good science. It goes completely against a much wider body of knowledge about organic material extraction, well beyond just coffee.

There's a lot of variables at play and it's not like we know much about that trial.

Also, please see the community guides. Treat comments in good faith (i.e. the strongest interpretation of their comment) and try to encourage productive conversations. IMO just quoting is degenerative to the conversation. Quote, but say more. Put your actual voice in the comment

That isn't a comparable experiment to what you'd get from sound wave espresso though.

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.

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.

"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.

If your goal is to understand the quality of the espresso shot, rather than experience a high quality espresso shot, letting it cool off provides a useful data point.

Would be awesome for industrial processes if it can be scaled, is comparable in price to heating water, and preserves what makes a good espresso a good espresso.

Was talking with a roaster who was providing espresso to a distillery recently. The distiller had tried a range of other products but only espresso shots were giving the flavour they were chasing. Needless to say, it ended up being a pretty limited run because the guys grew tired of pulling litres of shots for a batch!

I wonder if this process would work if the water were replaced with milk. Milk would degrade at high temperature, but this (at least in bulk) is at room temperature.

You think people who drink espresso would be ok with drinking milk? Also a majority of humans are lactose intolerant.

The majority of people that drink espresso drink it with milk.

The majority of Americans that drink espresso drink it with milk.

Really? The Last time I was in an American office, there didn't seem to be any milk around. They had an unrefrigerated bottle of "creamer" next to the coffee machine, but I was too scared to try it. I'm still not sure what it is, or how I'm supposed to use it.

It’s intravenous. You should try it!

Odd - when I'm at a cafe, I'm almost always asked if "whole milk" is ok. It work, we have fat free, 2%, and creamer...

Office coffee is not what people drink for pleasure -- it's a caffeine delivery device. If you go to a coffeehouse in the US you'll find that people often order drinks called Lattes which is espresso and steamed milk. And the word is Italian like espresso itself, so I think this isn't some weird Americanism but pretty traditional.

I did go to an American coffee house while I was there. It was called something like "Phil's" and there were no lattes to be had.

Every single coffee shop I’ve ever been in that serves espresso also serves lattes. Philz does not serve espresso, they only serve coffee. You went to virtually the only coffee shop in the US that does not serve lattes.

https://en.wikipedia.org/wiki/Philz_Coffee#Products

Creamer is a liquid made with oil and sweetener that approximates the taste and mouthfeel of milk and sugar. Or really a flavored syrup, not sugar. They often have hazelnut or vanilla flavoring added. You would use it by pouring it in your coffee, at about a 1:1 ratio with how you would use milk.

I'm surprised you associated it with espresso. Creamer and drip coffee machines go together. Milk and espresso machines go together. I've seem drip coffee machines with real milk, but I've never seen an espresso machine with just creamer.

It tends to exist primarily in office environments, because it can stand not to be refrigerated and was the first lactose-free option. Therefore it was easy to buy one bottle and solve the problem of "stuff to add to coffee".

It was a "Keurig", and I had to put a pod in it and wait a few seconds. Is that not espresso?

I make espresso at home by grinding/tamping it myself so I admittedly don't know much about the pod version or whether that still counts as espresso.

It is not an espresso. The temperature and pressure are lower than an espresso machine. The results would be considered analogous to more American style coffee. Meant to be drunk from a full mug (~177ml to ~298ml), etc.

It's marketed as a coffee machine that makes a single cup with a single pod at a time.

(Apparently you can tweak a Keurig to approach an espresso, but it's not the default).

Not only Americans. In my home country of Spain espresso with milk is pretty much the default coffee at bars ("café con leche").

Have you lost your mind 8)

Espresso is so named because you "express" the brew from the beans and you do that with water because water is pretty neutral in flavour, is not poisonous and has quite a few other properties that we have evolved to exploit or live with.

Milk is a weird liquid associated with mammals nursing infants. We humans have evolved to be somewhat lactose tolerant post infancy which is rare in animalia (1)

Given that we are using the Italian word - espresso - then let's use their definition. If you add milk then you have a latte or a cappuccino or an americano con latte, a flat white or whatever.

Real weirdos try to milk oats. I've tried but I can't find their teats.

1. https://en.wikipedia.org/wiki/Lactase_persistence

....surely you must have heard of macchiato(espresso with a dash of foamed milk) at some point in your life?

And lactose free milk is a thing, for those of us who can't have lactose anymore.

a latte?

as in, a glass of just milk?

If we are using italian definitions, "latte" is just a glass of milk.

Depends on where you live.

Lol.

Sometimes I wish HN had flags of where the person is living next to the username or something. This is obviously true for some/many places in the world, but also probably sacrilegious to even think out loud in others.

FWIW, once you poor milk into your espresso, it stops being an espresso, and depending on the coffee/milk ratio (and milk preparation), you know have a Cortado, Cappuccino, or a number of other versions.

So ultimately: no, no one drinks espresso with milk, it's not a thing, they start with an espresso, then turn it into a different espresso-based coffee drink :)

Not in general, but I think some people would be ok, and that's all that's needed for that question to be interesting.

It is a myth that an espresso shot 'dies' if you let it sit. A good espresso shot won't become worse.

Call it what you want, but it certainly becomes less enjoyable.

Agree to disagree.

Espresso, pour overs and even cupping shows you different aspects of the coffee when it cools. In fact, if you follow SCA cupping protocol, one of the most important parts is to evaluate the coffee at room temperature.

I can't recall any amazing cups I drank that became worse when they were cool (both V60s and espresso). They become sweet and syrupy, less harsh and bitter. They taste like juice and it just makes you joyful for some reason, it is almost unbelievable that this is coffee.

No, that’s a fair point. I definitely have certain coffees I still quite enjoy after they’ve cooled, and others that I really, really don’t.

I disagree. I have done the experiment a lot because often I make two shots and reheat the second one. It's noticeably less flavoursome and much less aromatic than the first.

No, reheating for sure will evaporate some compounds and might even overextract it, especially if there are still tiny particles in the coffee - like in moka or ibrik (cezve). Again, drink your shot at room temp or close to it. If brewed correctly, it would be somewhat close to tea or juice. It will still taste good, just cold. Mostly as coffee cools it becomes less bitter, more sweet and a tiny bit pleasantly acidic, more clear and less oily.

Some coffeeshops even recommend to taste it while it cools off and not drink straight away.

At WBC judges need to evaluate coffee as it cools down. Some people brew coffee using extract chilling - over a cool steel ball or using chilled portafilters.

I really don't understand how this myth of 'dead' shots still exists.

> Again, drink your shot at room temp or close to it.

I, um, do not wish to do this.

> Some coffeeshops even recommend to taste it while it cools off and not drink straight away.

Those coffee shops can with their own business.

This is only true for poor quality coffee. The hot temperature masks defects (bitterness). Good coffee tastes better as it cools. https://www.baristamagazine.com/the-temperature-paradox-why-...

Even that article carries on about the experience of having the coffee hot, eg

"This doesn’t mean drinking room-temperature coffee exclusively. The complete experience encompasses the entire temperature journey." and "High temperatures deliver immediate aromatic impact—the unique, irreplaceable value of fresh coffee."

I'm also not sure bitterness should be considered a defect in coffee, it's part of the flavor profile and actually peaks in perception at a higher temperature according to that article.

I find this is definitely true for americano and pour overs but I don't drink enough espresso to know if this also true? I at least feel the sentiment that you want to drink an espresso fairly quickly although I do enjoy savouring it and also drink water in between to re-experience it on the palette

> I at least feel the sentiment that you want to drink an espresso fairly quickly although

There is so many different ways and subjective taste palettes that I don't think there is one way. When I was younger and in a rush, I always drank my espresso maybe 30-60 seconds after they made it, the heat became part of what I enjoyed (eventually). Now I let it cool down to just above room-temperature if I know the place has good beans/roast as I feel even more flavor then. If I'm drinking a Americano, then it pretty much ends up room temperature before I even start drinking it.

Then we have my neighbor who I end up at the same cafe in sometimes, who poor their espresso into a glass of ice, then drink it, and they seem to enjoy their coffee just as much as me, so in the end, I don't think there is a right way here :)

To play the devil's advocate, though, you wouldn't drink espresso at 80 degrees, no? Provided the cup is warm to begin with, you could brew at 50 degrees and still have perfect temperature espresso for drinking? Those 30 degrees are bound to save a bunch of energy, I'd think.

Although if the cup is warm to begin with, then you're using energy to warm up the cup which would eat into those energy savings.

The "optimal" drinking temperature of espresso is still considered higher than 50 degrees, like 60-65 degrees, though of course that is subjective, but the nice aspect of serving it hotter is that those that enjoy it hotter can have it and then it cools quickly and the customer can choose when to enjoy it or get to enjoy it at multiple temps.

It's relatively common around here for people (especially older folks) to order coffee extra hot. Holding the coffee for a while and smelling it as it cools to a drinkable temperature is all part of an enjoyable process.

I'm always wary of studies that claim that there is some optimal way to have coffee. People have different preferences.

> I'm always wary of studies that claim that there is some optimal way to have coffee. People have different preferences.

I've gone one step further and is wary of any study that claims something highly subjective can be "optimized". "Best way to X" or whatever is always bullshit, just do what you feel like, aim to do whatever you find is fun and life will work out.

A large percent of espresso in the US is drunk iced. Iced Americanos, iced lattes, iced shaken espressos.

If you don't need to heat the water before cooling it down it would be an enegy savings.

"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.

Thanks, I'll know for next time.

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.

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?

> 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.

Even if that quote was left in, "espresso drinkS" usually stands for drinks based on espresso, not espresso itself. You know, like cappucino or macchiato.

Correct. An espresso drink may have milk in it. An espresso does not.

Edited to remove because the paper clarifies that it’s black coffee. But missed the (edit- found the clarification). Was quoted whilst in the process of fixing!

There are much greater sins against Italian coffee than dropping a word that doesn't change the meaning. "Espresso drink" vs. "Espresso-based drink"? come on.

For those sensitive souls I'd think they'd be more worried about "Expresso","Frappacino", "Puppacino", Starbucks, and 20oz "venti" lattes.

A mocha is an espresso drink. A latte is an espresso drink. A cappuccino is an espresso drink. An espresso is an espresso drink. Some espresso drinks have milk in them and some don't. Anyone offended by the question, "did the espresso drinks have milk in them?" is just looking for something to be offended by, as seems to often be the case with people who fly off the handle over the topics of coffee, pasta, and pizza.

> Espresso does not have milk

You're using the term in an unnecessarily specific way.

> 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).

It has probably been 10-15 years since I've had anything from Campos. Wasn't a fan. Will give it another shot if I get caught in Sydney again.

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....

Maybe there can be an ultra-sonic laundry machine

I guess a nuclear submarine doesn’t have the same power bill sensitivity as common household. ;)

There are! And you can buy them for a couple bucks.

The biggest downside: rinsing. You have to do it manually. And no, just refreshing the water and letting the ultrasonic emitter run will do nothing. And doing it manually takes a surprising amount of time.

Thanks! I googled after posting my comment here. No viable path with ultrasonic washers.

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.

Wow. In that environment you'd be getting the equivalent of a pack of cigarettes a day, even as a non smoker

Interesting you might only meed 15s of water to shower (assuming you can turn off while soaping) so 5 pause 10, allowing a luxurious 4 showers a week.

> Submarines didn’t always have laundry services [...] Everyone smoked tobacco all the time, everywhere

When the choice is between the smell of unwashed and sweaty sailors with dirty clothes, or smoke, ashes, fag-ends and tobacco, then surely the latter beats the former.

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.

I often produce espresso that is bitter and sour.

The best coffee that I've drank for the past five years have all been pour overs (my favorite was at a place called The Library in Toronto). I sometimes wonder if all the time, effort, and money I've dumped into espresso has been a huge mistake and maybe I should just buy a pour over setup...

You could get an OXO rapid brewer. It can make amazing espresso-intensity (TDS wise) drinks, and can be diluted to be as enjoyable as a pourover.

Also shoutout the library. Great shop

What you’ve hit is uneven extraction. Parts of the puck were over extracted and other parts under extracted.

Usually the cause is channeling, where some pathways in the coffee puck are easier for water to get through, so they get eroded first which leads to even more water going through these channels. Coffee around these channels then gets over extracted (bitter).

Conversely, much less water is reaching the other parts of the puck, leading to those parts getting under extracted (sour)

Better puck prep helps. Using a WDT tool (some acupuncture needles on a cork would do) or a blind shaker to break up the clumps leads to good results. Making sure the surface of the puck is level after tamping is a big one as well.

What also helps is going coarser in the grind. The coarser the grind, the less puck prep matters and the less channeling occurs. Warning, you’ll no longer be getting the thick crema you may associate with espresso, or the instagram worthy beautiful rat tail extractions. But the coffee produced from coarse grind espresso is IMO much better.

I was taught a lot of this by Lance Hedrick and I applied these learnings to achieve mostly consistent fruity and sweet espresso on most mornings.

If your espresso is bitter and sour, you're getting uneven extraction. One reason for this includes channeling: water encountering a tightly-packed puck and boring a hole through it or even lifting the puck so that water flows around it. Channeling over-extracts the areas of the puck that experience a high flow rate and under-extracts the areas that experience low flow.

Channeling is usually caused by too fine of a grind. If your machine (I'm assuming it's a pump machine) is pegging the pressure gauge at max (and dumping excess pressure internally) and your coffee tastes unevenly extracted, you may want to try grinding coarser. Not only will this reduce channeling, it'll result in less fines in the cup, also reducing bitterness.

The best thing I ever did for my espresso was to give up on the rigid rules I was first taught as a beginner. I don't time my shots, I don't use fixed brew ratios, I do everything by feel (watching the pressure build and the coffee flow) and taste. I do use a scale (for weighing beans per dose and weighing shots for repeatability). I dial in by adjusting the coffee output rather than fiddling with the grind. I only set the grind once to get a reasonable pressure (6-9 bars, no maxing out or dropping off), then fine-tune the gram output.

The biggest insight I gained from this freestyle approach is that the standard 2:1 ratio is altogether wrong for most of the light-roasted coffees you get from specialty coffee roasters. They simply will not extract properly with that small amount of water. Grinding coarser and pulling a longer shot (sometimes called a "turbo shot") gives you a much better result.

Don’t forget that pour overs are usually a lighter roast than espresso. I like a sharper tasting vote and so usually use filter roasts (lighter) for my espressos.

Edit: and if you want a non-bitter coffee, skip the pour over and cold brew, and go straight for the cold drip (one drop every second over 24 hours). And when from the fridge, let it sit to get to room temperature - now you have a non-bitter, flavoursome coffee that has a whiskey mouth feel

"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

Guessing you like your espresso bitter?

“Saving up to 75% of energy by not heating the water is a minor benefit for home users or small coffee shops. But for companies making ready-to-drink coffee products at industrial scale…”

The instant and dried coffee market is $35B-$50B. Cold Brew another $3B-$4B.

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.

You’re missing the real cash cow here: industrial scale production.

That’s a very good point, I’d wager that the energy input cost for industrial scale coffee brewing is a larger portion of the overall cost than it is for a shot pulled in a cafe. Reducing input energy by 75% in that case is huge, it’s like switching from resistive heating to a heat pump, any operator would jump at the chance to save that money if the process time is comparable and the ultrasonic brewing equipment plus lower energy costs has a lower amortized cost than the existing plant.

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.

That's very surprising. What's the model of machine?

It's called the Osma Pro.

https://www.engadget.com/osma-pro-cold-brew-coffee-machine-r...

Sadly, the company that made it flew a bit too close to the sun. I'd be genuinely sad if mine broke.

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.

Look into balcony solar, if you have a balcony with sun exposure.

California energy prices are among the highest anywhere, so anything you can do to cut usage will have a bigger payoff there, and justify some investment to achieve it.

How much do you pay for kWh?

(I'm not the person you're replying to, but I live in San Diego too.)

We have the most expensive electricity rates in the country - both summer and winter are over $0.50/kWh.

I just checked my plan yesterday, I pay 0.13 Eur, summer and winter. I can commit to my provider for a year and lower it to 0.11, but with slightly higher fixed monthly cost (which is about 50 eur, regardless of consumption). With this prices you less likely to think about the efficiency of fans - it will probably will years to return the cost of fan replacement.

I pay 0.45 Euro for public car charging, returning the cost of installing a charger at my (rented) house will probably take 2 years.

You may want to do a basic audit of your electrical usage -- it's not unheard of for apartments to have messed up circuits where one pays for usage by another.

If you turn off all of your AC consuming devices is your meter still registering usage?

Were you running all those fans on high 24/7? Three 150W ceiling fans and a 50W box fan?

$200 / $0.50 = 400kWh / 720 hours = 556 watts of load on average, which is more power than I use to run a 1-ton AC unit on auto.

BLDC motors are fairly common these days in HVAC equipment, speed control is much easier and they’re more efficient.

> I am going to switch over to a bunch of DC tower fans which claim to cut energy usage substantially.

I’m guessing they’re made by Vornado?

Perfect guess! They have a lot of DC fan options

No air conditioning? In San Diego? Most people find that climate control makes up the vast majority of their power bill.

Depends on which part of the county you’re in but within a few miles of the coast you can go no AC for all but 4-6 weeks if you don’t mind a few warm afternoons

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?

> And most iced coffee is very intentionally not made with espresso

Really? How is it made?

By soaking regular ground coffee in water for 12 hours or so.

You may be thinking of cold brew, which is usually more expensive due to the higher coffee-to-water ratio. A standard ‘iced coffee’ at most coffee shops is espresso-based

Huh. I never drink cold coffee so I always assumed they were one and the same. Thanks for the correction.

This is not true.

A standard iced coffee is just regular brewed coffee that is then put in the fridge. (Which is different from cold brew which is brewed in the fridge.)

Absolutely not espresso-based.

By making regular hot brew coffee and putting it in the fridge.

If you go to any random cafe and asked for an iced coffee, that's what they're going to give you.

If you want something else, you have to ask specifically for cold brew, or a specialty drink like an iced latte or something.

Iced lattes are a pretty common drink and near ubiquitous menu item.

Iced espresso drinks are the large majority of what people buy at, e.g., Starbucks.

Most iced coffee that people buy is not iced espresso drinks. Those are specialty drinks.

Think an iced coffee from Dunkin Donuts or McDonald's or whatever instead.

Eh, I think lattes are definitely the most popular drink at Starbucks and Dunkin.

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

How long does it take for water to boil? This is slower but still not by much.

If you have a thermoblock espresso machine, the brewing part can be over and done with in all of 1 minute.

But either way, the time consuming parts are preparation and cleanup.

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?

In the style of Benjamin Buford "Bubba" Blue:

"You got your cold brew, your Japanese iced coffee, your iced americano. Then there's your mazagran, that's coffee with lemon juice, real refreshing. Your espresso tonic. Your iced latte, iced cappuccino, iced macchiato. You got your iced mocha, your frappuccino, your Greek frappé. Vietnamese iced coffee with the condensed milk dripping down real slow. Affogato, that's espresso poured right over ice cream. That's... that's about it."

I do!

I think almost everything tastes better at room-ish temperature.

(Some things need to be colder or hotter to keep their texture, but I can't think of anything that _tastes_ better outside of the 16~25°C range)

Sparkling water (8-10C is the recommendation on the bottle in my hand). Bread (fresh from the oven, toast). Chicken Soup. And leaving aside examples, many things do taste better when they are hotter then 25, the heat helps more particles reach the olfactory receptors in your nose.

I'm sure that is correct for many people, but as I said: to _me_ things taste better at around room temperature.

Even though I don't doubt your claim that some particles travel easier at higher degrees I suspect the difference is too small to notice before the rise in temperature becomes distracting to _me_.

Well, you know what's taste good and what's not - for you. You are the only judge for your own experience, and taste is an experience of the brain, not something out there. Nevertheless, most people do prefer hot meals, and there's scientifically explanation for that.

Yeah not for me. I like my coffee hot. Scalding hot. McDonald's was great until they had that lawsuit.

Fine for iced drinks or Americanos. Even drinks with hot milk might be ok. I guess it's not so great at a neat shit of espresso.

s/shit/shot/g

The target of this process is not the residential use, but industry processing.

Instead of heating water to extract coffee and then latter cooling it to freeze dry and make instant coffee you keep the whole process at low temperatures, saving lots of power.

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.

It’s ultrasound so presumably it will be difficult to hear

You know what they say, when you presume you make a pres out of u and me

I have an ultrasound cleaner and it definitely vibrates and is noisy.

I think that's just a sound cleaner.

Every ultrasound device makes sound, sometimes a lot of sound, because it's vibrating all of the materials, liquids, and air around it.

So does every piece of baryonic matter in the universe, in which case I am proud to be an ultrasound device.

Affirming the consequent fallacy.

"Ultrasound machines vibrate everything around them therefore make sound" does not imply "I vibrate everything around me therefore make ultrasound."

Applause for the pun.

When working with ultrasound, I think of it the context of a micro-agitator versus the large scale shaking, snipping, and slapping clothes against rocks methods.

but that could be fixed by isolating the device from the environment, the ultrasound would not be heard, unless you're a bat.

Then the dog barking and the cat screeching through the house will do it then.

Ultrasonic welders sound like all daemons of hell rising up to get you. So... I wouldn't be too sure.

The actual research paper:

https://www.sciencedirect.com/science/article/pii/S135041772...

Yeah, if I drink an espresso and it's not hot, I'm fighting the barista.

It's lose-lose. With this they won't even have a hot drink to throw in your face as you hop the counter.

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?

There's probably 10 types of ready to drink coffee at Costco. Someone is drinking them, in bulk. Including my wife and daughter (different people)

Not sure the parenthesis was required but I laughed.

> [...] 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

Is it sarcasm?

In any case, I think there are frauds in all ranks of universities. I've seen people in CMU steal someone else's research idea or even a whole paper and the university doesn't punish the professors who did this. It's the PhD students whose work and life gets destroyed by such things.

I'm pretty sure the original comment is about Colombia's reputation for great coffee.

^-- this comment was typed on a computer, similar to the computers the worlds most advanced AI is developed on, so you know he knows what he's talking about.

Yes, that's why.

If it was by an American, i wouldn't trust a research about coffee

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.

Such an HN comment. I drink coffee for the taste, I’m sure I’m not the only one.

Is power consumption really the issue. Or just more consistent flavor?

For industrial production, power use.

For home use I'm much more interested in being able to add it to cold drinks and desserts.

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.

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.

Monopoly/duopoly is more a US thing.

hahahahahahahhahahahahahha

More likely they will ban it to protect the Italian heritage of the traditional espresso.

is there prior art to the EU banning a new technology to protect an old one?

GMO etc is arguable but there’s limits around what you can call some things based around how they are made.

Not really I think, but it’s not uncommon to protect product by restricting production methods or ingredients to traditional ones. So name espresso could be legally restricted to only when it’s brewed in traditional way.

Black bean drink (compare to es×r××so).

I suppose it's plausible that labelling might be required but what makes you think the EU would ban it?

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