Most of the coffee consumed is prepared using hot water, but recently there has been a very large rise in the popularity and market share of cold brewed coffee. Cold brew is coffee that is prepared using room temperature water and steeping times that range from 8 to 24 hours (this is not the same as iced coffee, which is hot-brewed coffee that is served over ice), and this is supposed to alter the flavor, aroma, and compounds of the finished product. Major coffee chains such as Starbucks and Dunkin' Donuts have jumped in with various products to capitulate on this market complete with claims of delivering a rich, smooth coffee with an inherently sweeter flavor reminiscent of dark chocolate and producing a drink that is not as acidic as that made using hot water. As with many food fads that first hit the scene, there are many strongly held claims made about the importance of things like the steeping times ("9.95 hours at 1 drip per every 0.8 seconds") or grind type based upon reasonably-sounding science, but very few claims that are supported by actual evidence.
In a recent paper in Nature Scientific Reports, Megan Fuller and Niny Rao at Thomas Jefferson University investigated the differences in the concentrations of caffeine and acid (3-chlorogenic acid) in four different coffee samples when brewed both by hot and cold methods. They took medium and dark roast coffees in both medium and coarse grinds.
Their results found:
- Acid and caffeine were found at higher concentrations in cold brew coffee made with medium roast over dark roast
- Grind size did not significantly impact the acid or caffeine level in cold brew
- Caffeine was substantially higher in cold brew over hot brew for coarse grind, but not statistically significantly higher for medium grind
- Acid concentration and pH levels were comparable between hot and cold brew methods
- Acid and caffeine concentrations reached equilibrium in only 6 or 7 hours instead of 10+ hours that some suggest is necessary
Previously: How Cold Brew Has Changed the Coffee Business
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Artisanal coffee, anyone?
Cold brew was still a relatively niche market until 2015, when Starbucks introduced the drink in a number of stores; it is now available at every one of its more than 13,000 locations in the United States, 800 of which also offer nitro. It's a coffee with both mass-market appeal and indie credibility. Today, you can find cold brew at a coffee shop where everything is meticulously crafted by hand, and at a Dunkin' Donuts.
The drink's range is expanding even more rapidly when you count canned, bottled and packaged coffees, called "ready to drink" within the industry. You can get that New Orleans-style iced coffee in a school-lunch-size milk carton, or that nitro cold brew in what looks like a beer can. Ready-to-drink, which has long been available in Whole Foods and other upscale markets, is now appearing everywhere. As of last month, you could find bottles of Slingshot Coffee, made by a small-batch company in Raleigh, N.C., at nearly 250 Target stores in the South.
What is cold brew? Essentially, it is a preparation. You steep coffee grounds in room-temperature water (which isn't "cold," strictly speaking) for six to 20 hours (depending on the recipe) to make a concentrate that can be diluted with water and served over ice. By giving up heat, you have to add time.
Cold brew is more than a slowed-down version of hot coffee; it's a noticeably different product. Hot water will bring out the acids in coffee, a characteristic that professional tasters call "brightness." Cold water doesn't but still gets the full range of mouthfeel and sweetness. The absence of acidity in cold brew is even more pronounced when compared with the iced coffee from the dark ages (of a few years ago), when it was almost always made with hot coffee that was chilled in the refrigerator. When hot coffee cools, even more acids develop, many of them unpleasantly harsh.
Cold brew coffee, and nitro.
The chemistry of cold-brew coffee is so hot right now:
Cold-brew coffee is so hot right now, and not just with hipster consumers. Scientists at Thomas Jefferson University in Philadelphia have been taking a deeper look at the underlying chemistry to better understand how the cold-brew method alters coffee's chemical characteristics, with an eye toward pinpointing the best way to cold brew the perfect cup. They had originally planned to present their results last month at the American Chemical Society meeting in Philadelphia, but the COVID-19 pandemic shut that down. So instead, they presented the information in a virtual poster session.
[...] "It turned out that there is a lot of research on coffee but not much research on cold-brew coffee," said Rao. That's partly because the biggest coffee-brewing countries (Italy, Turkey, Brazil, Colombia, for example) are all devoted to hot-brew coffee, like espresso. The cold-brew trend is mostly centered in North America.
"There are a lot of studies on espresso," said Rao. "We thought it would be a good idea to put some information out there for consumers and enthusiasts like me who want to make their own cold-brew coffee."
In one paper, published in 2018, Rao and Fuller measured levels of acidity and antioxidants in batches of cold- and hot-brew coffee. But those experiments only used lightly roasted coffee beans. The degree of roasting (temperature) makes a significant difference when it comes to hot-brew coffee. Might the same be true for cold-brew coffee? To find out, the pair teamed up with one of their undergraduate students, Meghan Grim, to explore the extraction yields of light-, medium-, and dark-roast coffee beans during the cold-brew process.
(Score: 0) by Anonymous Coward on Friday December 22 2017, @05:42PM (7 children)
"Acid concentration and pH levels were comparable between hot and cold brew methods"
The cold-brew I've had certainly seemed less acidic than the regular. I totally bought into the logic that hot coffee increases in acidity as it cools, and experience lead credence to the notion that cold-brew did an end-run around this phenomenon. Cold-brew is definitely less acidic than cold hot-brew, at least. Maybe that's where the claims originally came from.
(Score: 0) by Anonymous Coward on Friday December 22 2017, @06:31PM
I wonder if the temperature was taken into account, and how it buffers with saliva.
(Score: 4, Informative) by frojack on Friday December 22 2017, @07:07PM
I haven't noticed any significant difference. In fact, I've never found any difference worth the hassle of making the cold brew, and keeping it around in the fridge to stave off having to make it daily for the next day.
I've tried course and medium ground, Long steep. I've used various roasts. I've pretty much given up on cold brew as not worth the mess and the planning. You want a richer coffee? Stop buying crap beans! Try some Ethiopian Harrar, Swear off any Asian (western pacific) beans.
This is true of regular brew as well. People mistakenly think that a dark roast has more caffeine, but that's not true, caffeine is a volatile compound easily driven off by roasting. The lighter the roast the more caffeine - the brew method has nothing to do with it.
No, you are mistaken. I've always had this sig.
(Score: 3, Insightful) by JoeMerchant on Friday December 22 2017, @07:24PM (1 child)
Perceived acidity != pH
🌻🌻 [google.com]
(Score: 0) by Anonymous Coward on Saturday December 23 2017, @03:01AM
Your comment is marked "insightful", and you may well be right, but you have offered no real information. Care to expand on that?
(Score: 1) by Crash on Friday December 22 2017, @07:48PM
What made a significant difference for us, was switching from a cheap drip coffee maker, to a model that keeps the water preheated in a tank, and a metal basket (instead of plastic) such as one of the Bunn Velocity Brew models which brew a full pot in 3 minutes.
The coffee clearly tastes better, and also takes much longer until the coffee starts to taste burnt from remaining on the heating plate.
(Score: 0) by Anonymous Coward on Friday December 22 2017, @08:24PM (1 child)
The cold brew stuff is typically sold at a higher price, and I wonder if they simply use higher quality coffee beans for the cold brew product.
I tried to make cold brew a few times but gave up, I couldn't strain the grounds out well enough so it ended up being too weak or tasting like there was sand floating in it. I went through two different regular coffee makers over the years, but the coffee came out so bad that decent instant coffee tasted better. My wife bought one of the Ninja brand coffee makers this summer, and though I couldn't tell you why the resulting coffee tastes better. So we use that.
(Score: 0) by Anonymous Coward on Saturday December 23 2017, @02:38AM
Sounds like you're using too fine of a grind on the coffee. Cold brew grounds should be on the courser end of the spectrum and you should leave them to steep for a full 24 hours. And allow the coffee to drip out for a bit before wringing it out.
If it's too weak after doing that, then you're probably mixing too much water or other stuff with it. And you shouldn't have much in the way of grounds left.
I personally have one of those Ninja coffee makers for when I'm doing a hot brew and they're rather remarkable. IMHO, they're well worth the money, they're just not really a replacement for cold brew. Cold brew for things where you want cold brew and Ninja for everything else.
(Score: 2) by legont on Friday December 22 2017, @05:58PM (9 children)
What about acrylamide? The carcinogenic stuff?
They are looking for ways to decrease the level without much success for a long time, but if the cold brew makes darker roasts (which have lower acrylamide levels) more acceptable it's going to be a big win. Unfortunately most testers prefer to ignore the evil.
"Wealth is the relentless enemy of understanding" - John Kenneth Galbraith.
(Score: 0) by Anonymous Coward on Friday December 22 2017, @06:27PM
Just to emphasize that: according to Robert Nelson, president of the National Coffee Association [dailycoffeenews.com]
(Score: 4, Informative) by frojack on Friday December 22 2017, @07:23PM (3 children)
Even the people historically pushing the coffee=cancer nonsense [cancerresearchuk.org] have thrown in the towel.
That nonsense was started by the World Health Organization, and even they they have been forced to admit [statnews.com] they were wrong, and some say politically motivated. [washingtontimes.com]
No, you are mistaken. I've always had this sig.
(Score: 2, Informative) by Crash on Friday December 22 2017, @07:57PM (2 children)
Fearmongering.
Acrylamide is a chemical that causes the appearance of cancer cells in mice. While in humans, the same is potentially occur.
You know what humans aren't? Mice.
You know what else has been proven? Many studies using mice don't apply to humans at all. Because we aren't mice.
So Stop eating, it might cause cancer.
(Score: 2, Insightful) by legont on Friday December 22 2017, @11:41PM (1 child)
Yep, that's the food your typical milk and steak cancer free peasant would not eat. The answer to why we had so much cancer is probably simple - we eat bad food.
"Wealth is the relentless enemy of understanding" - John Kenneth Galbraith.
(Score: 1) by Crash on Saturday December 23 2017, @05:40AM
(Score: 4, Insightful) by JoeMerchant on Friday December 22 2017, @07:27PM (3 children)
Isn't this a bigger concern in starchy foods? I'm sure it's everywhere, but if you're getting 1000x the dose in a potato chip, why worry about what's in your coffee?
🌻🌻 [google.com]
(Score: 2) by legont on Friday December 22 2017, @11:34PM (2 children)
Coffee levels are actually quite high but there is almost no reputable research. Here is a summary https://www.superfoodly.com/acrylamide-coffee-cancer-risk/ [superfoodly.com]
Personally, I typically don't eat carbs, especially junk food with seriously high amount of acrylamid. For me coffee and bread are the only significant source.
For conspiracy nuts out there, sure, the seriousness of the problem would be denied simply because acrylamid is everywhere. Acrylamide free food would mean 95% of population is hungry. The story is interesting - just google for acrylamide in 2002. And yes, coffee industry is actively searching for ways to reduce the level, but the only known way is to make darker roasts which people don't like, while junk food manufacturers were somewhat more successful.
"Wealth is the relentless enemy of understanding" - John Kenneth Galbraith.
(Score: 1, Touché) by Anonymous Coward on Saturday December 23 2017, @12:19PM (1 child)
No carbs? And you eat bread? Care to explain that a bit?
(Score: 0) by Anonymous Coward on Sunday December 24 2017, @04:33PM
He's probably gluten free too except for normal white bread ;).
(Score: 5, Funny) by Nerdfest on Friday December 22 2017, @06:10PM (8 children)
Cold Brew Coffee: The "Monster Cable" of caffeinated beverages.
(Score: 3, Funny) by Nerdfest on Friday December 22 2017, @06:11PM (1 child)
Really, I think "The vinyl record" of beverages might be more accurate.
(Score: 4, Insightful) by Azuma Hazuki on Friday December 22 2017, @08:06PM
Nope. The fixie bike. Guaranteed to put hair on your chest, and then style that hair into an ironic man-bun. Even if you're a lady.
I am "that girl" your mother warned you about...
(Score: 2) by HiThere on Friday December 22 2017, @07:29PM
That's not true, it does taste different. In the 1970's or 1980's my mother preferred cold brew coffee. I, however, have never been a gourmet when it comes to coffee, except that I don't like really dark roasts. Actually, there are instant coffees that I find quite as good as fresh brewed, which tells you how gourmet my tastes are.
Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
(Score: 2) by captain normal on Friday December 22 2017, @07:35PM
Only if you go to the "Best Buy" of coffee shops...ie: Starbucks, Verve etc.
When life isn't going right, go left.
(Score: 2) by VLM on Saturday December 23 2017, @12:28AM (2 children)
As a tea drinker I feel kinda left out that we don't have anything cool and hipster.
Its just kinda weird to me, you bean brewers are full of interesting and exciting weirdos and us leaf brewers are apparently pretty boring people. Well, there are a lot of tea drinkers in England, so ...
The most exciting hipster thing I can think of for tea is I grew up a yankee tea drinker (aka normal) and I was ordered to the deep south thanks to uncle sam when I was a young man and the southerners take a large droplet of strong tea and mix it into a cup of corn syrup such that "southern sweet ice tea" pours like molasses whenever the air temp gets below 95F. And after consuming kilograms of carbs per day for a lifetime, then they wonder why most of them are fat, which is a whole nother topic.
(Score: 1, Informative) by Anonymous Coward on Saturday December 23 2017, @12:33AM
Cool and hipster = puer tea.
(Score: 0) by Anonymous Coward on Sunday December 24 2017, @04:45PM
I "cold brew" my Japanese green tea[1]. I just take the tea bag and stir it around in room temperature or cold water. Stir for a short while and it gets quite dark green. Or just cut off the paper tab and dump the whole thing in a water bottle and shake/stir it a bit (not too hard or the tea bag might burst). I find it's slightly less bitter this way.
[1] The tea I use is the OSK Japanese green tea - nothing very fancy, Tastes nice enough for me.
https://gd.image-gmkt.com/li/835/043/416043835.g_0-w_g.jpg [image-gmkt.com]
http://www.osk-odani.co.jp/product/pdf/02/62030.pdf [osk-odani.co.jp]
(Score: 0) by Anonymous Coward on Saturday December 23 2017, @02:41AM
Not really, I spend roughly the same amount of money on my cold brew as I do my hot brew coffee. In fact, I generally use the same beans, I just grind them a bit courser when I'm doing cold brew than hot.
Cold brew is awesome because you can make instant coffee. The first phase takes a ton of time, but after that, you can just add hot water and have your coffee hot. Or, you can add milk or other things and have cold or iced coffee.
(Score: 1, Interesting) by Anonymous Coward on Friday December 22 2017, @06:18PM (4 children)
My taste buds are nowhere near sensitive enough to taste the difference in coffee. I drink the thing not because it tastes nice (it doesn't) but because it attaches to a bunch of receptors in my brain that make it think that it's not time to sleep yet (i.e. it keeps me awake).
I find the whole coffee-scene very much populated with self-important, hipster nitwits who are saying things that make no sense... Case in point: in various pieces of research, wine-connoisseurs gave more points to bottles with a fancy label than they did to the same wine in a bottle that indicated a low or discount price. It's all bollocks and posturing anyway!
(Score: 0) by Anonymous Coward on Friday December 22 2017, @06:34PM (2 children)
I laugh at those gullible coffee snobs!
(Score: 0) by Anonymous Coward on Friday December 22 2017, @06:50PM (1 child)
For the ultimate in hipster coffee meet: https://www.yelp.com/biz/philz-coffee-san-francisco [yelp.com]
Pretty much all their coffee comes in weird assorted flavorings, it took somewhere between 5-10 minutes to get mine, and I tossed it in the trash outside because it tasted like shit.
(Score: 0) by Anonymous Coward on Friday December 22 2017, @07:02PM
Hah... "Barista"... there's a word without value. When I hear that word, I immediately think "oh, so you still got your novel inside of you then?"
(Score: 2) by JoeMerchant on Friday December 22 2017, @07:31PM
Then try some Starbucks peppermint-mocha iced from your local dairy case (spoiler alert: it is the nastiest concoction of weak chocolate and peppermint flavors layered on top of cheap coffee that I could imagine being sold at retail, ever. Starbucks has truly cashed in on their brand with complete disregard for future perceptions, if it weren't for the people who inhabit their retail outlets being incapable of repatterning their lives, I would say it's time to short the stock.)
🌻🌻 [google.com]
(Score: 3, Interesting) by Runaway1956 on Friday December 22 2017, @06:27PM (3 children)
Okay, I switch to cold brew. Then, I heat it up, because, you know, coffee is supposed to be warm. Hot, actually, but Mickey D's and old women pretty much put an end to that. So, cold brewed coffee doesn't have to be SERVED cold, does it? Does the post-brewing heatup do anything to these acid levels?
(Score: 0, Funny) by Anonymous Coward on Friday December 22 2017, @06:43PM
Heating coldbrew coffee will raise it's pH to at least 5.1. This is incredibly dangerous. Under no circumstance should you consume warm cold coffee.
(Score: 4, Informative) by pendorbound on Friday December 22 2017, @06:49PM (1 child)
That's actually quite lovely.
The flavor differences come from the brew temp more than the serving temp. Once the coffee is out of contact with the ground beans, you're no longer extracting additional flavors and chemicals from them. Brewing hot can extract additional compounds from the beans (which I personally don't care for the flavors of), but heating after the beans are filtered out obviously can't add any additional flavor compounds from the beans.
Your taste buds will tend to detect more flavors from a room temperature to lukewarm beverage than they will from ice cold though, so there's some difference between iced cold brew and heated cold brew. Since cold brew does tend to be stronger, I like to heat it from room temperature by adding a small quantity of boiling water. That approximates the dilution that comes from melting ice when you drink it cold. Starbucks usually waters down even their iced cold brew when they make your drink, but F-them. I'm assuming that's a cost cutting measure more than anything. By the time they put 3/4 of a cup of ice and an ounce of water, they're probably only giving you a double shot or so of cold brew.
(Score: 2) by HiThere on Friday December 22 2017, @07:31PM
There's also a difference in the volatiles which contribute to the taste via smell. It's not really important to me, but I do notice the difference if I warm the coffee after it cools.
Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
(Score: 3, Interesting) by All Your Lawn Are Belong To Us on Friday December 22 2017, @06:54PM (3 children)
Percolated coffee instead of drip.
Sometimes.
This sig for rent.
(Score: 3, Interesting) by Runaway1956 on Friday December 22 2017, @08:28PM (2 children)
I used to miss that percolator. I don't really miss the perc coffee, because I didn't drink coffee back then. The sound of the percolator went hand in hand with the smells of breakfast, and activity downstairs. I didn't become a coffee drinker until standing mid watches in the Navy - and even then the Navy didn't perc. I think it was two pounds of ground coffee that went into the basket, push a button, and something like five gallons of hot water dripped through it.
For the most part, Uncle Sam bought a medium to medium-dark roast, which I grew accustomed to. Now and then we got some dark roast, which almost everyone agreed should have been labeled "burnt". But, I think that was just a lack of quality control. The coffee people screwed up, burnt a few tons of coffee on a bad day, and just dumped it into those huge tins destined for the troops.
Oh, yes, those damned tins. Twenty pound tin cans of coffee. Opening those bastards often resulted in nasty cuts, that took a long time to heal. Didn't matter if you used a K-rats can opener, a knife, or a hatchet, or even a more traditional can opener, those cans always had ugly sharp edges. No big deal, you might think. YOU try reaching near the bottom of the can to scoop out some coffee while the ship is rockin' and rollin' in a storm. I hated those cans . . . .
(Score: 0) by Anonymous Coward on Friday December 22 2017, @09:58PM (1 child)
I actually boil water in the microwave with the grounds in it.
then I filter it out with a strainer and drink it
besides just gross to most people, is there a term for that method?
its sort of like having a percolator in that it gets to a roiling boil, and the coffee is essentially steeped like a tea--but with no paper filtration. its like I drink loose leaf tea except its coffee
(Score: 2) by Runaway1956 on Friday December 22 2017, @10:38PM
A term for that? Maybe "campfire coffeee". My curiosity is piqued . . .
These guys call it "cowboy coffee" - https://driftaway.coffee/how-do-you-make-cowboy-coffee/ [driftaway.coffee] Please read, it's rather humorous.
This guy has cowboy coffee, turkish coffee, and "bag it" coffee. Another good read - https://atlascoffeeclub.com/pages/how-to-make-coffee-without-a-coffee-maker [atlascoffeeclub.com]
Scott is a strange dude, but he has ideas too - https://driftaway.coffee/nomaker/ [driftaway.coffee]
This guy pretty much does a roundup of the previous methods, without as much humor - https://driftaway.coffee/nomaker/ [driftaway.coffee]
This last page is also worth a read, he has a couple methods of making cowboy coffee, one involving egg shells. https://www.homegrounds.co/cowboy-coffee/ [homegrounds.co]
(Score: 2) by takyon on Friday December 22 2017, @07:08PM (4 children)
It's the only safe coffee
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 2) by frojack on Friday December 22 2017, @07:27PM
Only because nobody drinks it, it harms only the environment.
No, you are mistaken. I've always had this sig.
(Score: 2) by VLM on Saturday December 23 2017, @12:30AM (2 children)
Safe coffee... interesting concept where does the condom go?
(Score: 3, Funny) by takyon on Saturday December 23 2017, @12:47AM (1 child)
mouth
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 2) by MostCynical on Saturday December 23 2017, @02:50AM
Tongue.
"I guess once you start doubting, there's no end to it." -Batou, Ghost in the Shell: Stand Alone Complex
(Score: -1, Troll) by Anonymous Coward on Friday December 22 2017, @07:37PM
So sb and dd are getting out of the cold brew game?
Not that i would go to these establishments to find out, in the first place, pretty sure they lace their shit with talc and rat poison, that any worthy hipstunkie would id on their salted carousel post fourth.
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(Score: 1, Funny) by Anonymous Coward on Friday December 22 2017, @09:13PM (2 children)
I prefer to just buy the raw beans and chew them. But if I must make it hot/cold, I use an old perculator I've used for the past 57 years, never cleaned not even once, and pour it into my equally old coffee mug, never cleaned. I don't use use a filter in the perculator either, just an old sock.
You wimps and your skinny venti double espresso with mocha served at exactly 103deg...
(Score: 0) by Anonymous Coward on Saturday December 23 2017, @12:31AM
What I wouldn't do for a decent cup of raktajino.
(Score: 2) by realDonaldTrump on Monday December 25 2017, @12:01AM
I don't drink coffee, it's very addictive. But those chocolate covered coffee beans are a real treat!
(Score: 3, Insightful) by acid andy on Friday December 22 2017, @09:25PM
I think they must mean "capitalize"
If a cat has kittens, does a rat have rittens, a bat bittens and a mat mittens?