[HN Gopher] Cold-brewing of coffee by picosecond-pulsed laser ex...
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Cold-brewing of coffee by picosecond-pulsed laser extraction
Author : bertolomeos
Score : 147 points
Date : 2022-07-22 11:52 UTC (1 days ago)
(HTM) web link (www.nature.com)
(TXT) w3m dump (www.nature.com)
| hericium wrote:
| > 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?
| mjlee wrote:
| 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.
| rsfern wrote:
| Also lots of journals don't even allow references in
| abstracts
| hasperdi wrote:
| 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.
| zoltar wrote:
| James Hoffmann tried it here:
| https://www.youtube.com/watch?v=2meeYcxXoVs
| andreareina wrote:
| N.B. not cold brewed coffee
| peddling-brink wrote:
| That doesn't sound food grade. Is there a method to line the
| cleaner basin with something food grade?
| hasperdi wrote:
| They put the drink in a mason jar
| https://youtu.be/YlQT4ptwLKs?t=15h34m
|
| And that jar goes in the cleaner
| daniel_reetz wrote:
| This also works for cleaning items in solvents and
| flammable liquid. Put a secondary reservoir inside the
| ultrasonic tank.
| tmikaeld wrote:
| 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.
| leobg wrote:
| 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?
| bertolomeos wrote:
| 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...
| tmitchel2 wrote:
| Hard to heat something transparent with light radiation,
| whereas I guess the powder can absorb it
| tmitchel2 wrote:
| So yes still heating? Ah no I see the alternate explanation
| now
| vanattab wrote:
| 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
| zemvpferreira wrote:
| 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.
| peteforde wrote:
| 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/
| clairity wrote:
| 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.
| atoav wrote:
| I am not a food snob in any sense, but cold brew tastes
| _very_ different from old coffee. It is not even close.
| sfmike wrote:
| My eyes read soma
| hn_throwaway_99 wrote:
| 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?
| dendrite9 wrote:
| 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?
| pushedx wrote:
| 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.
| ct0 wrote:
| 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.
| dangerlibrary wrote:
| What are the consequences of brewing in the fridge vs. at
| room temperature?
| amit9gupta wrote:
| 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
| goldenkey wrote:
| Fungus and mold will likely appear if you brew anything
| with water at room temperature.
|
| Use the fridge - trust my experience. It may take a bit
| longer to brew at colder temperatures, due to decreased
| convection of the liquid, but it will taste much better, as
| it prevents bacterial and fungal growth.
| hericium wrote:
| I believe fungi aren't too fond of caffeine.
| DontchaKnowit wrote:
| 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.
| foobiekr wrote:
| I wonder if this is that the grounds, post use, are
| somewhat sterilized and vulnerable to rapid colonization.
| goldenkey wrote:
| Perhaps, but I've cold brewed black tea enough times with
| moldy results to forewarn y'all.
| yunohn wrote:
| 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/
| traverseda wrote:
| 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.
| yunohn wrote:
| 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.
| krageon wrote:
| 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.
| traverseda wrote:
| 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.
| nibbleshifter wrote:
| Maybe lower extraction, but honestly, I'd have to get a
| refractometer or some shit to test it, and I can't really
| justify that expense.
| toss1 wrote:
| 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. "
| jghn wrote:
| Takes more time to get the right amount of extraction
| js2 wrote:
| 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 175deg and others at 190deg. 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.
| varispeed wrote:
| 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.
| kibibyte wrote:
| 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.
| AlbertCory wrote:
| 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.
| rsfern wrote:
| 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?)
| js2 wrote:
| 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.
| __alexs wrote:
| 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.
| 13of40 wrote:
| 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.
| nescioquid wrote:
| 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.
| sgtnoodle wrote:
| 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.
| nanomonkey wrote:
| The egg whites that remain on the shells also acts as a
| flocculant for suspended solids.
| 13of40 wrote:
| The trick for that is to use two identical bowls, one as
| a mortar and the other as a pestal.
| dskinner wrote:
| 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.
| Fargoan wrote:
| Oh. I thought you were going to say centrifuge
| anon84873628 wrote:
| 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.
| peteforde wrote:
| 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.
| anon84873628 wrote:
| 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.
| rvrst wrote:
| This is prime Ig Nobel prize material.
| seanhunter wrote:
| ...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.
| krageon wrote:
| If you've already fixed it in a french press why follow that up
| with a drip filter?
| ngcc_hk wrote:
| Are you for real ?
| ajaimk wrote:
| Just take my money!!!
| prewett wrote:
| 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.
| anon84873628 wrote:
| 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.
| titanomachy wrote:
| "Mass dispersal system" is a euphemism for "chemical weapon",
| right?
| kurthr wrote:
| Not the same, but pretty post apocalyptic:
|
| https://youtu.be/BHiWygziyso?t=943
|
| Devil's Toothpaste
| Alex3917 wrote:
| Similar to this, anyone here tried Osma and have thoughts?:
|
| https://drinkosma.com/
|
| (Extracted via acoustic cavitation.)
| anon84873628 wrote:
| Check out the Lance Hedrick review of this device on YouTube.
| selimnairb wrote:
| This has inspired me to try running room temperature water
| through my Flair espresso maker to see what happens. It's worth
| a shot!
| selimnairb wrote:
| 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.
| sgc wrote:
| 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.
| midislack wrote:
| tiborsaas wrote:
| Is this the sort of thing that bored engineers invent? :)
| aj7 wrote:
| 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?
| bbatha wrote:
| The paper proposes this as an _industrial_ process to reduce
| waste and brew time.
| xbar wrote:
| 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?
| ajot wrote:
| 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.
| findalex wrote:
| This is how general research works. For better or worse.
| amelius wrote:
| Also, they didn't scientifically evaluate the taste of the
| coffee using a test-panel? Disappointed.
| denton-scratch wrote:
| 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?
| ahsima1 wrote:
| 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
| syntaxing wrote:
| Besides just diodes, there's also the Q-pulsing aspect (hence
| the pico and fempto part of laser nomenclature)
| denton-scratch wrote:
| 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.
| syntaxing wrote:
| 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
| krastanov wrote:
| The warning is *NOT* exaggerated. It is incredibly easy to
| damage your eyes with these tools.
| sgc wrote:
| 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.
| thejosh wrote:
| It depends on the cold brew, they all have different tastes.
| hericium wrote:
| > 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.
| denton-scratch wrote:
| 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.
| anon84873628 wrote:
| 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.
| itronitron wrote:
| 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.
| foobiekr wrote:
| 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.
| peteforde wrote:
| 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.
| anon84873628 wrote:
| 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.
| GordonS wrote:
| 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!
| denton-scratch wrote:
| 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.
| GordonS wrote:
| 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.
| andreareina wrote:
| Yeah it's going to tone down the fruitiness, though some may
| remain depending on how fruit-forward your coffee is.
| tapland wrote:
| A lot of people say cold brew is fruitier. I'd give it a shot
| if I were you
| johnny_canuck wrote:
| 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.
| baxtr wrote:
| What's the recipe?
|
| PS: ofc I could google that. But then again google results
| these days are...
| bhrgunatha wrote:
| 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
| wrycoder wrote:
| I wonder if extracting the coffee with half the water and
| then diluting it gives a different result than just
| brewing at normal strength?
| petre wrote:
| 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.
| yawgmoth wrote:
| 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 uJ"? Perhaps they are one and the same?
|
| Where can I find cheap lasers to try something like this?
| rsfern wrote:
| 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...
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