Ultrasonic Coffee
theguardian.com
theguardian.com
https://news.ycombinator.com/item?id=40284823
Cold brew coffee in 3 minutes using acoustic cavitation (unsw.edu.au)
2024-05-07 (351 comments)
Interesting idea, always nice to see new ways to brew coffee. I wonder how easy it is to replicate their process? The article isn't hugely clear. It talks about using a modified off the shelf domestic espresso machine but the picture at the top looks like a custom built device with potential complex machining involved to build.
If it's the case you can buy an ultrasonic transducer and bodge it into an espresso machine lots of fun possibilities for coffee geeks (and to my point above someone like James Hoffman will give it a go and build up a bunch of interest in the technique)
If it's the case you need a bunch of complex machining and significant technical skills (say those possessed by chemical engineers conducting cutting edge research...) then I imagine this will struggle to go anywhere.
The whole idea sounds like it could be really simple once implemented, and in a world of super complicated coffee brewers with small little crevices that are hard to clean, it'd be very welcome.
If this just has to agitate the brewing area with ultrasound and not much else, there's no reason for it to cost a lot. Something like the Silvia you mention is just a lot more complicated.
Alternatively you could use a (quite affordable) ultrasonic machine designed for gentle cleaning of jewelry, dentures, glasses..
I've used one to extract fragrance from biological material for an artistic project[0], and it worked really well. Instead of having to wait for a few weeks for a tincture to finish, you put the same tincture (alcohol and material you want to extract fragrance from) into a plastic bag for just 15 minutes. Sure, it smells not quite the same, but the speed is often worth it. I've even heard about some guy trying to turn vodka into whiskey with an ultrasonic machine and wood chips.
There are quite a few ultrasonic machines on the market. I've tried EMAG and multiple Chinese no-name machines that are just as powerful but cheaper. Sadly the no-name machines are quite a bit louder - you can't stay in the same room while it's running basically. Still, they all work well for this kind of fast and dirty extraction.
[0] https://rybakov.com/blog/smelling_cz/ (second half of the page)
If I remember correctly, while ultrasonic treatment did a decent job of quickly extracting the various chemicals from their carriers, there were some caveats. The ratio of chemicals extracted could differ from normal, and it only did a partial job of accelerating the formation of very complex secondary compounds that form when the whole mix is properly aged.
So the difference in smell you found could be some chemicals being preferentially released over others, and/or the lack the secondary chemicals.
Speak for yourselves, the espresso I make is neither inherently bitter or harsh. It depends entirely on the recipe.
As a general rule, the lighter you go the harder it is to extract the coffee. The more expensive the equipment will need to be. To make good espresso from light roasts you can benefit from a machine which can handle flow profiling as the puck is so unstable at lower roasts that consistency becomes very difficult.
So you pick a medium roast, a good quality grinder (although even in the expensive range, different types and subtypes of burr will produce different results) and a quality machine which can hold a stable temperature.
Next, it's important to keep it all consistent, weigh the coffee, weigh the output. Things like WDT[0] can help get an even distribution of coffee in the portafilter, although recently people have started looking at shaking the coffee grounds as a better option, although there's some limited research on this. To go the extra mile, RDT[1] can help increase grind consistency, and so can freezing the coffee beans (although usually you want to single dose the coffee to avoid condensation on your frozen beans slowly causing the moisture content to increase). I also use paper filters below and above the puck, as well as a mesh filter on top of the paper filter, this helps distribute water, prevent clogging, and improve reliability (it's honestly quite a surprisingly noticeable difference).
Now for dialling in: You pull a shot, you taste it, as a general rule of thumb if it tastes empty and sour you should pull a longer shot (higher output weight), if it tastes bitter and/or salty then you should pull a shorter shot (lower output weight). Once your flavors are balanced you can adjust the grind to increase or reduce the overall concentration to your taste.
For medium roast I normally aim for 1:2.5 ratio (15g of ground coffee in, 37.5g of liquid coffee out) and adjust from there. The timing is a complex topic which depends highly on what you're trying to do, turbo shots naturally run very fast, blooming shots naturally run very long. You should try to get the machine to run between 20 and 35 seconds but if it tastes better if you go longer/shorter then don't blindly stick to this.
It's difficult to get good espresso reliably, and especially so when you are doing it at home and don't have a day's worth of customers to offset the cost of a wasted few shots. But it's possible. You also have to start over every time you get new coffee beans.
For reference, my setup is a Gaggia classic modded with flow profiling (gagguino mod) with a niche zero conical burr grinder. I live far enough away from London that Brita filtering the water produces good quality results, but some people may want to distill and re-mineralise water using a recipe for maximum consistency.
[0]: https://www.baristahustle.com/weiss-distribution-technique/ [1]: https://www.beanground.com/ross-droplet-technique/
I want to add a few things.
Once you know your grinder, too high a max pressure is not so much of a problem, as choking a shot becomes a rare issue.
Consistently good Espresso is easier using a slightly coarse ground, but something needs to give, like texture or concentration.
Taken together, cheap machines can work well, although learning on them can be frustrating.
Use fresh roasts, and use them up quickly. Some days after opening a bag of not single dose frozen beans , many coffees lose their good aroma, and only the roast itself remains.
Several times a week I use one of those stainless steel conical fine mesh filters to make a single cup of coffee. Pouring boiling water over the stainless mesh filter (into the sink), to preheat it, before adding the ground coffee beans radically improves the flavor of the coffee.
Not at all bitter or harsh. And I like my coffee cold rather than hot, though you can obviously heat it if you want it hot.
(Bonus: I'm lazy, and though the filtering stage is a little more effort, it's concentrated, and then I have instant good coffee for a week or two).
100% Arabica based coffee can be more palatable, depending on grinder quality, espresso machine, right grind size and some other factors.
Recently Red Bourbon is the variety that appeals to me most.
Italians will say this, then put a moka pot on the stove for five minutes until it's boiled through, and serve you the blackest, most burnt tar imaginable - stuff that could qualify as road building material - and then turn around and insult American food tastes whilst they've skipped two meals in favor of cigarettes and the lowest quality wine. But that's okay, because they have some expensive olive oil in a ceramic bottle for the last two years.
And you can't even accuse them of not having travelled enough, because half their young people are working across Europe, so they would know that there is better food out there in other countries - but they're doing that wine and cigarette diet so they remain ignorant and arrogant. They - you - are as bad as French people, but the rest of the world haven't discovered it yet.
Italian food is genuinely good, but is now, in my opinion, also too beholden to traditions and tribalism (food must be prepared in this way and you are wrong otherwise), and I perceive a relative lack of openness to different cuisines compared to some other countries.
Italian coffee is built on dark roasts of non-specialty (and often even Robusta) beans, which works well with milk-based drinks like cappuccinos but can also work well for espresso and moka brews too. Despite having a preference for lighter roasts I still enjoyed the coffee on my trip to Rome last year, and actually I would easily choose it over the big brand chains like Starbucks.
What I find Italy is missing is the so-called 'third-wave', where light and medium roasts are preferred and higher quality (think specialty or single-origin, typically always Arabica) beans are typically used. I believe that this is partly due to the fact that espresso prices are regulated in many parts of Italy to be as low as €1-1.50 and so the business model just doesn't work unless the beans are cheap too.
https://en.m.wikipedia.org/wiki/Prevalence_of_tobacco_use
It's also one of the world's top per capita consumers (and producer) of olive oil, so the chance of any given meal having old rancid olive oil in them is probably lower, rancidity being a function of throughout.
https://en.m.wikipedia.org/wiki/Olive_oil
Also, and I suppose that is subjective, Bialetti coffee can be delicious.
No, the Nordic way of light (or medium) roasted coffee prepared in a drip brewer is the only way.
If this breaks into Italy, I will make sure to stay away from it ;-).
That being said, I'm really enjoying weak watery coffee these days. Its sweeter, you taste the aroma more, and it's a nice slow high in the morning that teases you gently into a focused work mindset, instead of tense grinning-neurotic mess I used to be. Also, I can sleep better at night.
I've recently learnt that most Starbucks have filter coffee as an off-menu item. It's still Starbucks but it's so much better than their "Americano". Unfortunately many will refuse to make it for you (presumably because it's more effort).
It's not that espresso can't be good, but for most places this is the cheap, low effort, coffee-on-demand. And in most of southern Europe (Italy, France, Spain) the taste seems to be for burnt coffee that all tastes the same.
Also, it really annoys me that if you order two drinks (like a café con leche in Spain) they'll split a double shot into two cups with one getting clearly more coffee than the other. It's a 50% chance you're going to get the weak brown milk.
Disclaimer: I'm a Spaniard.
Most cafes in Spain serve a particularly noxious form of burnt coffee called "torrefacto" [0], which is made by mixing sugar with the beans while they are being excessively roasted. This introduces additional bitterness and ash to what would have already been overly roasted beans.
For a country where coffee is often consumed multiple times a day, and where there are cafes in every corner, Spain has disappointingly terrible coffee.
I'd rather have the brownish water they called coffee in the US office any day.
It made sense back in the day, in that postwar economy, as the sugar roasting process reduced its price and lengthened its shelf life. Mixing or even substituting in completely with chicory (depending on your wealth, or lack of it) was very common, and some old people still do it nowadays.
But still tastes burnt, so of course people do lots of sugar and milk on their coffee :p.
BTW, it's OK if any of you don't like coffee, or like it sugary, with milk, powdered, or in any coffee based drink that you like. I might be snobby with my coffee, but you can drink wathever do like. And in summer I always fancy a cold coffee with tigernut horchata (popular around Valencia, different from the Mexican one that's made with rice).
Sure, I agree. My disappointment with torrefacto is just a personal opinion.
For example, I think chicory is great, and so is barley (mugicha). I would very much rather drink those instead of torrefacto.
And it’s faster to order, too! At least at the Starbucks’ I’ve been to, the barista/cashier will usually turn around and pour it immediately. Other drinks (even iced/cold brew) go into the queue.
Nowadays most of our offices in Poland have espresso machines, so I can taste it here also.
What is funny is that when I was in our main office in US, they didn't have espresso machine, just some strange "coffee machine" that poured some coffee-like liquid.
I also don't get the big buckets of coffee premade and poured to the mugs in some traditional American diners.
In Poland the traditional way to prepare coffee is called "turkish style" (po turecku) - you put one or two spoons of ground coffee in glass or mug and pour hot water over it. I don't like that too much, but it tastes better than the US made version of coffee.
But the worst coffee, has to be the brown colored bland fluid called coffee in the US!
Similar with Sweden. Stockholm has many excellent coffee shops. Maybe you need to put more effort in.
The consistently excellent quality of coffee one got from any local cafe in Melbourne and Sydney was by far the highest I've seen anywhere in the world. Including Italy.
The only Starbucks I ever saw there was at the cruise ship terminal in Sydney.
I then moved to London and it was a very sad affair with coffee, I missed a good cup so much. Tho over the years they got more and more cafes that cared and had actually comparable coffee.
Agreed it's a shame people here are so proud of the "hustle" culture. Brooklyn is a bit better — I think you would really like SEY :)
Italian here. To those replying, this is the key takeaway. I think the poster means it'll take something insanely good for us to consider upending tradition. Not because we have the gold standard, but because we are so unbelievably stubborn and pig-headed :)
Compared afterwards to a mug left outside the ultrasonic cleaner. There was definitely more extraction in the ultrasonic cleaner, though the coffee was still fairly weak. Likely needs more time given that they are using a custom horn etc.
They also use 100W of ultrasonic power: https://www.sciencedirect.com/science/article/pii/S135041772... and a cursory search says this is the domain of more expensive ultrasonic cleaners (> 100$).
0: https://www.aliexpress.com/w/wholesale-ultrasound-transducer...
Probably best to just get a stainless cup, glue the transducer(s) to it and let it rip.
Perhaps a ziplock bag would work well.
(Don't think about elephants!)
I'd go with Sonicoffee ...
There's a little history of trying to get a new coffee method named: Clover comes to mind, a vertical extraction, high pressure, fine-filter plunge method that's like a powered Aeropress. The founder made it to be a kind of new price point offering between drip and espresso drinks. Starbucks ultimately bought Clover, and seems mostly to have shut it down, which is too bad - it was a nice product for third wave coffee shops to offer, and it's only rolled out now at high end Starbucks.
It is worth the wait, although maybe not the cost - it seems to exist to sell $10 "Blue Mountain" coffee at Starbucks now.
Anyway, I would guess this would sell more as an enthusiast home product than something that can fit in to existing coffee shops; the Clover story I think is that something new can be appealing, but it's probably not worth the counter space at indies; unless it can replace the espresso machine completely, e.g. as a mode in your existing espresso machine, it's not going to go into what is usually very crowded production space.
They more or less killed the original model, but they're pushing to deploy the new 'Vertica' model so that drip coffee is brewed on-demand rather than by batch. Ostensibly to reduce waste.
The output from Vertica machines is definitely subpar compared to the original, however.