Comment by kowalej | Hacker News Reader

Comment by kowalej | Hacker News Reader

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.

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.

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.

Thanks, I'll know for next time.

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