Last year I backed a project called Osma. https://drinkosma.com/

It uses acoustic cavitation to extract flavor and caffeine from coffee without any heating in about one minute.

I use it every day and I like it. I love the strong flavor of cold brew, and my stomach appreciates the lack of acidity. There is a learning curve but if you're a HN reader, chances are the amount of experimentation required to dial in your version of perfection is an upside, not a downside.

I paid less at the time, but today the kit is selling for US$695. Note that as with all things coffee, it's only as good as your grinder. I ended up pairing my Osma with a Sette 270: https://baratza.com/grinder/sette-270wi/

i'm honestly baffled by the cold brew fad, as every cold brew i've tried tastes like the day old, cold coffee that it is, not rich and nuanced like freshly hot brewed coffee.

but i'm with you on the grinder. i have the sette 30 and it's fast and consistent, with little waste. i primarily do single serving grinds for brewed coffee with it. the gearbox broke but baratza sent me a new gearbox for free (i believe there was a manufacturing defect in the early models). i got the 30 (the number of grind settings) because i wanted it primarily for pour over rather than espresso. the great thing is that the grind adjustment mechanism can be upgraded (along with the controller faceplate to get presets) and effectively turns the 30 into the 270, which i may do if i ever decide to get an espresso machine.

edit: i also got the courser burr, taking the grind size up to roughly a medium grind, which is perfect for pour over. the included burr is better suited to the fine grind needed for espresso.

I am not a food snob in any sense, but cold brew tastes very different from old coffee. It is not even close.

I agree, and I don’t much like cold brew. I’m not particularly a snob about brewing methods (I use a French press out of pure laziness exactly as a recent article making the rounds suggested), but I do have a snobbery about beans (light roast, generally natural process fermentation). I don’t think I even dislike cold brew per se, I think it’s just often wasted on nondescript coffee so there’s not much flavor to distinguish.

Now I’ll gladly destroy any hipster cred I might have accrued saying the above: I do quite like stashing half a pot of yesterday’s coffee, in an open pint glass, to make iced coffee for the next afternoon.

It sounds like you know your stuff, so I'm confused. What you're describing (old, cold coffee) is nothing at all like what I'm enjoying.

What comes out of my Osma is fresh, ice chilled (by uh, ice), rich and all of the flavor notes are present. There's a nice foam on top that is technically not crema, but cavitation bubbles. It's strong like a well-poured Espresso shot, but with none of the burnt acidity.

I promise you that if you cupped what comes out of my machine alongside a literal glass of old, cold coffee... one tastes like victory and the other would make you gag.

i'd love to taste yours in the hopes of finding something enjoyable. i've tried cold brew at some of the fanciest cafes in LA (with foam even) and none of them made me want it again.

it reminds me of the IPA fad with beer. i tried a bunch and they were generally extra bitter (and strong) rather than tasty. still don't get that one.

Same. I tried to like cold brew because I’m into coffee. I don’t know if I have a rare gene switched on or something because it tastes horrible to me. If other people were tasting what I’m tasting it couldn’t be popular.

yah, i can drink it, but it tastes old so i don't prefer it. at a cafe i'd much rather get a hot espresso drink (latte, mocha, or cappuccino) since i can't make those at home, and at home, delicious fresh hot coffee. i really don't 'get' cold brew, in either sense.

I can’t stand hot drinks of any sort except like hot chocolate in the winter. While iced coffee mostly hits the spot for a cold coffee, cold brew is a nice change every one in a while. So I’m glad the fad here even if the flavor isn’t as great as it could have been hot.

that's fair. to each their own.

Depends on the weather for me. Winter in NZ at the mo and I wouldn’t dream of it but a couple of years ago in Hawaii I walked past a cold brew coffee shop and it was exactly what I wanted.

I'm a little confused about the "acoustic cavitation" and what a "diaphragm pump" is.

The majority of home and "prosumer" espresso machines use vibratory pumps - how is this any different? Also, the recirculation of already brewed coffee back into the pump seems really strange to me. Didn't the coffee world decide percolators we're gross a couple decades ago precisely because of this reason?

Recirculation is possible with Osma but not at all recommended, officially or by me. If I saw Osma and thought it was a recirculation system, I'd be weirded/grossed out, too.

I'm not sure what a vibratory pump is, but acoustic cavitation is the same kind of action you can use to clean silver or wash clothes. Millions of tiny bubbles. Try a Google search for "acoustic cavitation cleaner".

I wonder if the cavitation is a reference to using ultrasound for extraction? Something like what is described here: https://www.frontiersin.org/articles/10.3389/fnut.2022.84981...

This looks like an interesting machine, I wonder if there's a way to try one?

My eyes read soma

Ha, this article sounds like some coffee-loving physics grad students procrastinating on their thesis, and their professor said, hmm, maybe we can publish this!

When the Mentos + Diet Coke thing was first a big thing, a friend of mine who ran a biotech firm (so was always writing funding proposals), submitted a proposal for an aerosolizer using a similar process, as a mass dispersal system for the military, if I recall correctly. Don’t know if it ever got funded, though.

There are several groups focused on coffee research. Lots to learn about taste perception, extraction dynamics, fluid flow, etc. And because the coffee market is so large, any discovery can have a big practical impact.

“Mass dispersal system” is a euphemism for “chemical weapon”, right?

Not the same, but pretty post apocalyptic:

https://youtu.be/BHiWygziyso?t=943

Devil's Toothpaste

I’m constantly baffled by cold brew coffee seeming like a mysterious and arduously-obtained concoction.

Stick ground coffee in some filter bags and put it in some cold water in the fridge. Come back the next day and drink it. Leave it in there however long you want.

I make cold brew in an Aeropress. I fill mine with fresh grinds and room temperature water at the start of making my breakfast and put it over a cup of ice. It drips most of the way through while I'm preparing my meal and I squeeze out the last bit of water as I plate my eggs, so maybe 5-10 minute brew time. I'm drinking a cup now.

It’s obviously weaker than hot coffee, but though I drink my hot coffee black, I prefer a weaker iced coffee with a bit of milk or cream. The only way to get a really strong iced coffee is either to brew hot and let it cool before pouring over ice or to make coffee ice cubes, both of which are too much trouble for me.

So between pouring stronger hot coffee over ice which melts a lot of the ice or pouring weaker cold brew over ice and melting less ice, the dilution ends up about the same, but the flavor profile is different with the cold brew being more subtle and less acidic. Truthfully I enjoy it both ways. Just depends on my mood.

The Aeropress is very flexible. Experiment with it. No one brew will work for all beans/roasts. I’ve found some beans/roasts taste better brewed at 175° and others at 190°. Besides the Aeropress, the thing that upped my coffee game the most is an electric kettle.

Other than percolated, there’s almost no brewing method I don’t enjoy. I use an Aeropress most of the time, but I also make coffee in an ibrik, a mokapot, a Chemex, a simple silicone pour over mold; it just depends on my mood.

The only style of coffee I gave up on at home is espresso. I was just never able to pull consistent shots and got tired of how much work it was to clean the machine and the space it took on my counter. And before you say it: I just can’t countenance pod machines.

Am I the only one who thinks areopress seem like a giant scam? I bought this and I honestly can't see a difference between simply pouring hot water over a ground coffee. Aeropress seems like a bothersome extra step that does not add anything, actually I think the coffee doesn't even taste that good from aeropress.

I left my Aeropress unused in my drawers for years for that reason, until some smart people worked out a technique that turns it into a highly effective immersion brewer. Check this technique out https://coffeeadastra.com/2021/09/07/reaching-fuller-flavor-...

The gist of it is: 1. Grind finer (like, nearly espresso fine) 2. Steep for much much longer (like 10 minutes) 3. Don’t press too hard

(3) is generally applicable advice and may already improve your current results. Pressing too hard results in channeling and uneven extraction.

Of course, goes without saying, use good coffee and an appropriate grinder.

How do you prepare the Aeropress coffee?

Do you use a metal mesh or paper filter?

Do you get enough pressure from your Aeropress? I've had several over the years and sometimes the plunger heads (the rubbery part going towards coffee) could be too loose as they can become weak over time.

Or your coffee is ground too coarse perhaps?

The point is you need proper pressure and a slow push. The plunger and ground size impact the pressure most IMO.

Of course, without the filter you won't get pressure at all :) And if you use the inverted method and forget the filter (like me, several times), once you flip over the Aeropress, your kitchen ends up smelling awesome.

The water temperature should not be boiling or you'll burn the coffee, possibly making it taste bad. I tend to use 94-95 degrees Celsius unless advised otherwise.

An Aeropress won't create a flavor smash like espresso, there's not enough pressure for that. But for my admittedly crude and uncultured taste buds it can basically beat a coffee machine.

By the way, there are add-on espresso gadgets for the Aeropress, I've the Fellow Prismo and in my opinion it works quite well. Making larger amounts, like a triple espresso, is a hassle though.

For espresso-like strong coffee, I just use the good old Moka pot. Slightly more work than Aeropress, especially regarding the cleanup, but not that much.

Also, a tip about the ice cubes: make strong coffee with the Moka pot, freeze, then dump the cubes into a smoothie blender (with milk if you like) before drinking. Saves you the mindfulness exercise of watching ice cubes melt.

I do this too, but I like to use the inverted aeropress method, and I put a bit of honey in at the end before I put on the filter and flip it over a cup of ice. It’s my favorite iced coffee method

(Just saw you use room temp water; I use hot and let it brew for like 2min. Do you get a strong enough extraction? How long do you let it go for?)

When brewing with room temp water it doesn’t seem to matter much whether I press the water through right away or let it sit for 10 minutes and then press it. It is not a strong extraction either way. I’ve expanded my comment since you replied.

I just had some of this last week. I'm not a cold brew drinker, more out of habit than anything else, but it was delightful! Make the exact same way you would an espresso shot.

You don't even need filters. Shove ground coffee in a plastic bottle. Fill it with water. Shake it briefly. Leave it in the fridge for 8 hours. Pour the coffee out slowly so the grounds stay at the bottom.

Several years ago I spent a few weeks in a country that as far as I could tell didn't have a "coffee culture" and all that was readily available was packets of instant coffee. I hunted around and found a vacuum packed brick of ground coffee at a shop, but didn't have any equipment to brew it. Then I worked out that you can throw some in a glass bottle, pour in some hot water from the kettle, let it sit until everything settled to the bottom, pour out the liquid, and "voila!"

Later on the trip I bought a Turkish coffee maker, which works on the same principle, so it's not so much an innovation as it is a hotel survival tip.

Cowboy-coffee is just a pot with water and coffee grounds on a fire. Apparently there is a trick involving adding egg-shells to the grounds to make them settle more quickly (never tried it, though).

Glad you prevailed! My nightmare scenario is having coffee, but no way to grind it.

Beat the coffee grounds into an egg while bringing water to a boil, then get the whole mass into the water. Can boil for an extended time (say 3-5 minutes) and use old stale coffee and it will improve the flavor and keep the grounds suspended in the boiled egg making the pour off easy.

That's a very common misconception. The egg shells are for their calcium carbonate, in order to cut down acidity and improve the flavor. The classic trick to causing the grounds to settle quickly is simply to add a little bit of cold water at the end of brewing.

The egg whites that remain on the shells also acts as a flocculant for suspended solids.

The trick for that is to use two identical bowls, one as a mortar and the other as a pestal.

This is the best way to do a French press too. Pushing the plunger all the way down just disturbs the grounds that have already settled. Better to keep the screen at the top of the liquid level then pour out slowly.

And the cupping procedure doesn't even do that, but still produces reliable tasty cups.

Oh. I thought you were going to say centrifuge

Cold brew should be brewed at room temperature, then stored in the fridge. It's considered cold because it's not brewed at 190*f.

What are the consequences of brewing in the fridge vs. at room temperature?

I have a very sensitive stomach; I get an upset stomach (watery stools) and pimples all over my forehead and head when I have coffee. With cold brew, (if made properly), I do not get any of this. So there is definitely some difference in the chemical constituents of hot-coffee vs cold-brew-coffee. Some other papers state less caffeic acid and less quinic acid.

https://www.nature.com/articles/s41598-018-34392-w

In the Abstract part of the paper, they highlight some distinct chemical differences to validate that their process works more like cold brew vs hot brew:

>> "Furthermore, the liquid phase’s alkaloid content, analyzed by reversed-phase liquid chromatography coupled to high-resolution mass spectrometry, is dominated by caffeine and trigonelline and is comparable to traditional cold-brewed coffee rather than hot-brewed coffee. Furthermore, analyzing the head-space of the prepared coffee variants, using in-tube extraction dynamic head-space followed by gas chromatography coupled to mass spectrometry, gives evidence that the lack of heating leads to the preservation of more (semi-)volatile substances like pyridine, which provide cold-brew coffee its unique taste. "

Different fats dissolve at rates that are temperature-dependent (which is why cold brew has a different flavor to espresso - a different subset of the oils in the bean have dissolved into the water). As a result, each brewing temperature would have a different rate of extraction for each fatty compound.

This is why temperature / pressure / flow rate are so important to good espresso - some of the heavier compounds taste very bitter and including much of them in the brew makes for an unpleasant drink.

I'm not a doctor or a biologist. But I do have a water cooler and have brewed both alcohol and cold brew in the past. There's no super special sterilization process for cold brew, we don't use sterilite on the spike that opens up the bottles, we don't store the water in an especially cool place, or otherwise take any special precautions.

That water turns out fine, often for weeks at a time.

Store the cold brew out of direct sunlight, don't leave the grounds in for a super long time, and you'll be fine. It's not like brewing alcohol, you're not adding a bunch of sugar to it or anything like that. The coffee grounds you're adding are shelf-stable, the water you're adding it to is shelf-stable, you're not introducing any real food for bacteria/fungus. Water will eventually go off if you leave it in direct sunlight (mostly due to algae), especially after introducing extra organic matter, but the actual risks of following established methods for brewing cold-brew at room temperature are very low in my opinion. Especially chlorinated water like you probably get out of your pipes.

This is nonsense. Fungus and mold takes a while to develop, and most probably that timeframe is not over night in ground coffee (or tea). It is still better to do it in the fridge, because if you put it straight in it's less work and tastes good if you leave it overnight.

Overnight, sure. But I like my extracts/brews super strong. After a couple of days you will get mold growth.

Cold-brewing can reliably be done at food-safe refrigerator temperatures over multiple days, safely. The longest brew I've heard used at any coffee shop is 8 days, though I've never tried more than 5 (usually 1 to 3).

Right, that's what I'm saying. If you try to cold-brew non-refrigerated for more than a day, you'll get mold.

As someone who has terrible kitchen cleaning habits- definitely not true lol.

Wet coffee grounds will grow mold quicker than any other food product I've seen.

Even a pot of coffee will get mold on the top within like a week.

I wonder if this is that the grounds, post use, are somewhat sterilized and vulnerable to rapid colonization.

I believe it has more about the lack of airflow and the compaction and moisture.

Mold (a fungus) has grown in my refrigerated cold brew enough times for this to be false.

More here - https://kitchenappliancehq.com/can-cold-brew-coffee-mold/

Huh... that hasn't been my experience. I notice that article uses a lot of affiliate links, are you sure it's not fear-mongering in order to sell it's special cold brew coffee maker?

Not saying that mold is impossible, but I don't think the solutions is to buy their amazon affiliate coffee maker and special coffee butter.

If you have mold issues after 24 hours of cold brewing I think you have some deeper issues at play. Consider getting mold tests for your house, sterilizing the tools/containers you use, and switching out your beans.

I wasn’t endorsing the article, merely providing it as evidence of mold following my anecdote.

I generally face it 3-4 days in, not 24 hours.

Perhaps, but I've cold brewed black tea enough times with moldy results to forewarn y'all.

Takes more time to get the right amount of extraction

My read of the materials presented is that this process is legitimately faster (three minutes vs 8-20 hours) and makes no claim about easier.

Sure, you can just make some that will be ready tomorrow. But if you want some right now, it seems legitimate that being able to press a button and get cold brew is novel.

If that doesn't sound like you, don't buy it.

Most coffee innovations are focused on cafes as the customer. If you can make on-demand cold brew you no longer need to worry about anticipating demand, throwing away waste, etc. You can probably even market the "fresh brewed" aspect of it.

Cafes will make an effort to increase extraction yields 1% because that means 1% less coffee needed over the many pounds used per day.

I've never drunk cold-brewed coffee. According to the article, cold-brew has "less acidity and bitterness".

I happen to like coffee with fruit and citrus tones. I'm not a coffee bore, but I have understood that coffee bores refer to that fruitiness as "acidity". Does that mean that cold-brew would be less fruity? The authors take "acidity" to mean "pH", which is obviously easier to measure than "fruitiness", but I wouldn't describe the taste of e.g. spirit vinegar as "fruity".

Supplementary question: why's it got to be a picosecond laser? They say that a nanosecond laser's pulses are too long, and cause heating. How hot does it have to get for that to be a problem? Can't you just cool the brewing vessel?

Supplementary supplementary: can apparatus for doing this be built at home? How much ps-laser power needs to be delivered to the brew? At what wavelength? You can get handheld picosecond lasers for things like mole and tattoo removal, for under $100; would one of those do the trick?

You cannot get picosecond lasers for under $100, not even under $1000. Those devices that you see are dangerous diode lasers that do not work for the advertised application, lie about their specs and are supplied without adequate eye protection. Youtuber Styropyro made a video about them here https://youtu.be/DbzbIGkPW-o

Thanks for that! So those devices on Amazon are just powerful diode lasers that switch on and off ten times a second - they're not even millisecond pulsed lasers.

That powerful beam looks like (dangerous) fun; I've always wanted a laser that can burn things. My inner arsonist would like to be able to set things on fire from 100m. But I'm sure the device must be illegal here.

Styropyro says you can damage your eyes just by looking at the projected laser spot. I wonder whether he's exaggerating his warning a bit.

OK, so no homemade picosecond-laser coffee for me any time soon.

The warning is *NOT* exaggerated. It is incredibly easy to damage your eyes with these tools.

I bought a cheap cat toy laser on amazon that was so powerful our eyes hurt just from testing the thing on our light gray walls etc. Some things are not worth messing around with.

Not sure what you’re being downvoted but Styropyro is correct. There’s one other aspect that people don’t talk about and that’s Q-pulsing. When you turn on 10W diode, the room gets pretty bright from the stray light. The moment you turn on Q-pulsing, the room glows uncomfortably bright, even with eye protection

Besides just diodes, there’s also the Q-pulsing aspect (hence the pico and fempto part of laser nomenclature)

> I happen to like coffee with fruit and citrus tones.

That would likely be seeds of Coffea arabica - one of three coffee plants. Those tones come from a specific plant rather than a brewing method or temperature.

The other popular is C. canephora (robusta coffee) which is almost globally (outside espresso world) considered as inferior to arabica and cheaper. Robusta has some chocolate and nut aromas but some people would say that it resembles burned rubber stench.

The third plant - C. liberica - is very rare in comparison. To me it has a somewhat woody/smoky/fruity aftertaste but I have only tasted beans from two roasters so far.

Most of store-bought ground coffee are arabica/robusta blends so people can enjoy full taste spectrum but aren't discouraged by the burned rubber thing.

I, on the other hand, LOVE robusta and my morning ritual of throwing mainly robusta roast (currently from Harley Estate in India) with 5-25% arabica seeds of choice into coffee blender is the best and most benefiting first decision making process I can imagine in the early morning.

When people talk about the flavor of "third wave" specialty coffee, they are talking about C. arabica.

The current US Barista Champion (Morgan Eckroth) did use C. eugenioides in one of her beverages, but that is still priced out of reach for all but the most dedicated enthusiasts.

Robusta is only used in "traditional" espresso blends (meaning the original Italian style) or, stereotypically lower quality products. (Edit: not to denigrate anyone's choice of using Robusta in their morning cup - please do whatever you enjoy the most.)

The thing about arabica is that there are many different varieties, from Ethiopian heirlooms to Typica, Bourbon, Pacamara, Gesha, etc. They are grown in varied soils, elevations, and climates. And as a sibling comment points out, the "natural process" and experimental fermentations are becoming popular because of the secondary flavors imparted. (Though my view of the scene is that most snobs still scorn natural process coffees for lacking cleanliness).

The brewing method and temperature will ABSOLUTELY alter the flavor tones of the cup. And the quality of grinder is the most important factor by far. Tweaking grind size can take you from a flat, mediocre cup to something with distinctive flavors and sweetness.

I've noticed that espresso barristas seem to favour robusta.

> Those tones come from a specific plant

No doubt; but I'm sure that "terroir" and growing conditions are also important.

Also, from what I can tell there are two ways of separating the berry-pulp from the bean: mechanical separation and wet fermentation, which create different flavour profiles.

The two I'm alternating at the moment are both pure arabica, both from East Africa, and both high-grown; but they seem to be processed differently.

You might enjoy Japanese iced coffee.

I find that cold brew tastes the same no matter the quality of coffee (therefore great for lower quality coffees) where as Japanese iced coffee retains the original notes of the coffee.

Is it any different from espresso fredo? In South Korea they drink iced americano, which is espresso dilluted with water and then dilluted with ice. In Greece I always drink espresso fredo as most shops will make a good cup and frappe is just not my cup of coffee.

What’s the recipe?

PS: ofc I could google that. But then again google results these days are…

It's a pour over method [1]

You can also use a regular drip machine though. Use half the normal water. Add the equivalent ice (by weight) to the flask. Brew as normal, but turn it off as soon as it's finished. The slow drip of hot coffee is cooled immediately as it hits the ice.

Since the brewed coffee is cold, you can add extra ice to your cup without it melting and diluting the taste too much.

Adjust the water / ice ratio as desired.

[1] https://www.youtube.com/watch?v=Y3jxJv5UiPg

I wonder if extracting the coffee with half the water and then diluting it gives a different result than just brewing at normal strength?

It is different but still tastes fresh and robust

It really depends what coffee beans you are starting with, and the roast, just as it does with "regular", hot brewed coffee.

I also like lighter-roasted fruity beans, and cold-brewed tends to reduce the "sourness". IMO cold brew really shines for non-fruity beans though, greatly reducing the bitterness.

You should try it!

Hmmm. I've been alternating Ethiopian Harrar with Kenya AA. I buy them ready-roasted - I don't know how to characterise the roast other than "medium" (the beans don't glisten with oil). I alternate specifically to catch the fruity aroma, which seems to my jaded old palate to fade after a week of the same bean.

Fruity varieties are almost always a light or medium roast - often you can see this in the colour of the roasted beans, which will be much lighter; I'm colour blind, but I think they're more brown/tan than black.

Earlier this year I had a cold-brewed coffee from a local coffee shop that tasted more like lemonade (unsweetened) than coffee. It was bad, and I'm not sure if the cold-brew was the exact trigger or just the final nail but I haven't had any other coffee in the months since then despite drinking coffee multiple times per day for years and years.

I'm so sorry that this happened to you. It legitimately sounds like you were either pranked or offered a product that contained something humans are not intended to drink.

There's absolutely nothing about cold brew coffee that is anything like unsweetened lemonade. I'm cringing just reading this.

What it does taste like is super-strong coffee, with none of the burnt note that comes with heated coffee. It could very easily be considered "too strong" by supertasters... but unsweetened lemonade sounds like dishwater.

The "burnt note" doesn't typically come from the brew method, but rather how darkly the beans have been roasted.

Light roasted (aka "Nordic" or "third wave") beans will produce more acidic cups because of their different chemical components. They are also less likely to taste burnt or astringent.

Lots of coffee shops think that tannic, acidic coffee is good coffee.

For those in the bay area, Red Rock in Mountain View has this issue with their brewed coffee. It's often downright sour.

Yeah it's going to tone down the fruitiness, though some may remain depending on how fruit-forward your coffee is.

A lot of people say cold brew is fruitier. I'd give it a shot if I were you

It depends on the cold brew, they all have different tastes.

I drink cold brew coffee. Normally I leave the coffee to brew for 24 hours. I’m considering of buying ultrasonic cleaner for brewing my coffee. I wonder if that’s going to work.

Watching YouTube videos on smoking / flavouring liquor using these cleaners gave me the idea.

James Hoffmann tried it here: https://www.youtube.com/watch?v=2meeYcxXoVs

N.B. not cold brewed coffee

That doesn’t sound food grade. Is there a method to line the cleaner basin with something food grade?

They put the drink in a mason jar https://youtu.be/YlQT4ptwLKs?t=15h34m

And that jar goes in the cleaner

This also works for cleaning items in solvents and flammable liquid. Put a secondary reservoir inside the ultrasonic tank.

So how does that work? How does the laser help extraction? Is it like they’re just heating small bits of grounds over at a time for short durations only, as opposed to heating the whole heat and all the water at once? So still heat extraction?

A German article [1] summarizes the technique as using the laser to reduce the size of coffee grains without generating enough heat to break apart the aromatic compounds. Based on this explanation, I would say this method is not equivalent to heat extraction.

https://www.scinexx.de/news/technik/skurril-cold-brew-per-la...

Hard to heat something transparent with light radiation, whereas I guess the powder can absorb it

So yes still heating? Ah no I see the alternate explanation now

Queue a Kickstarter to buy an expensive but extremely attractive coffe-laser brewer, expected to arrive July 2023, already in pre-production with "not"-rendered images.

Similar to this, anyone here tried Osma and have thoughts?:

https://drinkosma.com/

(Extracted via acoustic cavitation.)

This has inspired me to try running room temperature water through my Flair espresso maker to see what happens. It’s worth a shot!

Just tried it with some medium roast beans. I ground it a little finer than normal. The water shot through very quickly, like 1-2 seconds. I poured the results back into the brewing vessel and pressed it through again. This time it went through slower (likely because the coffee was saturated by this point) and even made a little crema. It’s not quite cold brew, but reminiscent the of cold brew. Definitely worth more experiments.

Try pre-infusion. Press slowly until you get one or two drops through, wait 30 seconds or so for the grounds to absorb water, then finish the single pass as slow as you can reasonably do so.

Check out the Lance Hedrick review of this device on YouTube.

...or you can just make a French press/cafetiere using cold tap water, put it in your fridge overnight and in the morning plunge it and run it through a drip filter. It's not complicated, the equipment is super cheap, and the coffee is delicious.

To the extent there's a surprising secret, the coffee will taste better if you grind it fine like espresso rather than coarse like you normally would for French press/drip coffee.

If you've already fixed it in a french press why follow that up with a drip filter?

Because if you use fine-ground coffee some of it will go through the filter on the french press and give you sludge in the bottom of your coffee.

Are you for real ?

Yes. I know the idea of making coffee using lasers is super-cool. I'm just making sure everyone knows how to make cold brew, because it's really nice.

I had trouble understanding the method - were there 2 lasers? "Nd-YAG-laser centered at 532 nm" and "A ps-laser (Edgewave) with a pulse duration of 10 ps, a repetition rate of 80 kHz, and pulse energy of 125 µJ"? Perhaps they are one and the same?

Where can I find cheap lasers to try something like this?

I think the second sentence is just describing the manufacturer and the pulse configuration of the one Nd-YAG laser. Sometimes a second laser is used to pump the output laser in pulse laser systems, but that’s an implementation detail and I’m not sure about the specific system used here.

You might be able to find a laser system to hack around with (they are used for tattoo removal). Probably not cheap.

Make sure to take laser safety super seriously if you work with lasers https://ors.od.nih.gov/sr/dohs/safety/laboratory/Pages/laser...

Hot (or Cold) Take: Coffee preparation rituals exist because atheists are looking to replace theology-based rituals and traditions they have forsaken.

I bet you would get similar results just putting your container of coffee in an ultra sonic clear type deal. Probably a lot cheaper then buying picosecond pulsed laser

Unfortunately far as I know coffee sonication produces horrible results. If I remember reading correctly the sonication produces a lot of cavitation on the surface of the grounds and leads both to the extraction of horrible flavours as well as the suspension of micro-fines in the brew that never settle. The reputation is it being undrinkable.

This is prime Ig Nobel prize material.

Is this the sort of thing that bored engineers invent? :)

Right tool for the job award goes to these guys

Utter nonsense. And everybody got paid for doing this. An industrial grade picosecond laser is $150k. It has so little throughput that it must be used only for very high value products.

In fairness, did anyone notice a finding in this paper that might lead to a cost-effective process by a different technology?

Was this the April 1 issue?

Utter nonsense is an exaggeration.

Is this good, important, or foundational science? I do not think so, but there may actually be practical applications for rapid production of high-caffeine cold brew coffee.

Do you find the method fraudulent or were the outcomes poorly selected or measured?

Maybe not even coffee. Maybe this can extrapolate to other liquid extraction methods from ground solids, if it can help reduce heating, or time for processes that are nowadays done at room temperature. Think minerals, beer, soy-sauce; economies of scale could afford this type of technology.

I think you are right that I was immoderate.

The paper proposes this as an industrial process to reduce waste and brew time.

This is how general research works. For better or worse.

Also, they didn't scientifically evaluate the taste of the coffee using a test-panel? Disappointed.

> Cold-brewed coffee is attributed to health benefits, fewer acids, and bitter substances.

IMO statements like this have no place in scientific papers. Attributed by whom? Less bitter than which method of hot brewing? Fewer acids than what - coffee made with all hot brew methods including AeroPress?

If you make it past the abstract, all this is reasoned through or referenced. I think it's quite normal for an abstract to lay out the basic premise of the paper without diving in to detail immediately.

Also lots of journals don’t even allow references in abstracts