Cold-brewing coffee
Background:
Summer is upon us. After resuming my cold-brewing regimen, I'm finding that cold-brewing coffee isn't working as well as I seem to remember it did last summer.
For those unfamiliar with the process, you take ground coffee and let it sit in cold water from 12 to 24 hours, then strain it. You should end up with a coffee concentrate, to which you add hot water.
The main problems are that the coffee is significantly weaker than it was a year ago. I'm using the same proportions, the same volume of water, and, unless I'm misremembering, the same amount of brewing time.
The only way I can get a reasonably strong concentrate is by brewing for 12 hours, replacing the grounds with fresh ones, then brewing for another 12 hours. (I haven't tried a straight 24-hour brew yet.)
The question:
I've used three kinds of ground coffee, and the best results are from pre-ground Chock-full-o-nuts. (A local brewer's beans and Peets beans both produced weak, watery coffee that can't be diluted. Both used fresh beans.)
Aside from the obvious (use moar coffee, etc), what can affect the strength of the concentrate? Might the quality of our water have changed? Are there environmental factors to consider?
Best Answer
Grind
You're using a fine grind? I've always found grinding it myself to extra-fine works best for cold-brew. – Bruce Alderson
and
I pour it through a standard mesh a few times, then a mesh + cone filter. The resulting coffee is thick, dark, and has very low acidity (very nice over ice with a spot of condensed milk). – Bruce Alderson
Bean Age
If the beans themselves have been sitting on the shelf for longer - it means they have lost a lot of their fresh, volatile flavours. May not be the only reason - but it definitely affects the flavour you'll get. – Taryn East
Temperature
Is the ambient temperature cooler, perhaps? It doesn't sound like you moved, but maybe it's a cooler beginning of summer, or you're using more AC? [...] – Jefromi
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Can any coffee be brewed cold?
Any variety will work, and you'll find that it tases less bitter when its steeped in cold water instead of hot. It would be fun to compare a glass of cold brew coffee with hot coffee of the same variety.What is a cold brewing method for coffee?
Cold brew is really as simple as mixing ground coffee with cool water and steeping the mixture in the fridge overnight. The next day you strain the mixture, leaving you with a concentrate (it's strong, so you'll want to dilute it) that can be served right away or stored for up to two weeks.What is special about cold brew coffee?
Cold brew coffee tastes less acidic than hot brewed coffee from the same beans, and it's famously mellow and smooth\u2013\u2013not just on the palate, but also the stomach.Is cold brewing coffee better?
It's sweeter and smoother \u2013 Because the coffee grounds aren't exposed to high temps, cold brew coffee usually tastes more flavorful and less bitter. Some people find that they need less sweetener and cream when drinking cold brew, which is great if you're cutting back on added sugar or watching your calorie intake.How to: Three Ways to Cold Brew Coffee
More answers regarding cold-brewing coffee
Answer 2
I used to work in a coffee shop and we would regularly make cold-brew coffee. How we did it was to grind whole beans on the finest setting we had (Turkish coffee) and to fill a porous bag, tie it off, submerge in water, cover, and place in the fridge for 12 hours. After the 12 hours waiting period, take the water-soaked bag out of the bucket, and place in a colander (preferably with a handle) over the bucket until most of the water drains out. Squeeze out the remaining water and dump the grounds. With about 3-3.5 pounds of ground and a 5 gallon bucket filled 3/4 of the way (with the bag inside), we did not dilute the mixture after brewing.
Answer 3
From everything you've said, it sounds like a temperature thing.
Did you leave the coffee sitting in a sunny window last year? This could have warmed the water significantly. Maybe you kept it closer to a hot oven or something? Those are the only environmental changes that I can think of that would affect your brew.
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