Cheap, easy, no-mess cold-brew coffee

I've just finished teaching week four of the amazing Clarion Science Fiction Writers' Workshop at UC San Diego; in addition to spending a week working closely with some very talented writers, I came up with a new and cheap way to make astounding cold-brew coffee.

I bought a $10 "nut-milk" bag and a plastic pitcher. Every night before bed, I ground up about 15 Aeropress scoops' (570 ml) worth of espresso roast coffee -- the $20 Krups grinder is fine for this, though I wouldn't use it with an actual espresso machine -- leaving the beans coarse. I filled the bag with the grind, put it in the bottom of the empty pitcher like a huge tea-bag, and topped up the pitcher with tap water (distilled water would have been better -- fewer dissolved solids means that it'll absorb more of the coffee solids, but that's not a huge difference). I wedged the top of the bag between the lid and the pitcher and stuck it in the fridge overnight.

In the morning, I took the bag out of the pitcher and gave it a good squeeze to get the liquor out of the mush inside. Add water to the pitcher to fill to the brim and voila, amazing cold-brew. You can dilute it 1:1 or even further.

Cleanup was easy: invert the bag over a trashcan or garbage disposal, rinse off the bag, and you're ready to go.

This produced very, very good coffee concentrate, with only a little grit settled into the bottom 3mm of the pitcher (easy to avoid). It may just be the cheapest and easiest cold-brewing method I've yet tried.

See also: HOWTO attain radical hotel-room coffee independence

Notable Replies

  1. Oh no, you didn't actually just recommend that Krups POS did you??? Its not actually a grinder, it's spinning blades that chop up the beans and get super hot which actually cooks them while it's doing the chopping, leaving inconsistent sizes (thus impossible to properly extract) and further burnt beans. Please please please if you care at all what your coffee tastes like don't ruin it with a blade "grinder"

  2. mak says:

    I don't have tons of money, and care about my coffee. My solution is to use a blade grinder in short bursts while shaking it to move the beans around. Avoids burning and gets somewhat more consistent grind. I also don't attempt to make espresso this way.

  3. Thanks for the nut-milk bag tip - I just followed your link and bought one.

    I had been using gallon-sized freezer bags (inside a tall container to keep them upright) and pouring the coffee through a strainer into my cup; it makes nice, powerful cold coffee but it's a pain. This should be much, much less hassle.

    To all the people hatin' on the blade grinders: absolutely true that you don't get a consistent grind. If that's a make-or-break for you (which it shouldn't be, with this brewing method) then sure, don't use a blade grinder. But if you're burning your coffee with it - Jaysis, you're doing it wrong! If you loaded up a blender with frozen fruit, and didn't stop to stir it, would you blame the blender for producing a small amount of warmish liquid and a whole bunch of frozen chunks? It's the same concept, and a bladed coffee grinder is a lot easier to stir than an Osterizer...

    • Load the thing
    • Pick it up in both hands, with your thumbs holding the lid down and one thumb over the GO button
    • Shake it gently while you pulse the power, so you're not continually grinding the same thin layer of beans
    • Stop when you think the grind is about as fine as you want it (after about the third time you do this, your ear will tell you when)
    • Done!

    It ain't rocket surgery. True, you don't have to do this with a burr grinder - but I've never seen a travel-cheap ($15!), decent burr grinder.

  4. When I want to find out way too much information about coffee, I turn to

    Conclusion he reached:
    1) Coffee brand doesn't much matter much. Use cheap coffee. Cold-brewing does not produce all of the flavor compounds as hot-brewing.
    2) Extraction time anywhere between 12 and 24 hours -- doesn't matter much.
    3) Use 167 grams of water to 25 grams of coffee. This produces (120.4+170) 290.4 grams (which I'm assuming is 290.4 cubic centimeters) of finished coffee, which is 1 big mug of coffee. Obviously, this can be scaled up.

    As for grinders -- for an espresso machine, uniformity of grind is crucial, because the extraction time and pressure can vary, causing straight-up bad results. For a french press, uneven grind means that grit finds its way through the filter. For a drip or pour-over, there's almost no grit ever, so the grind might affect the flavor, and how much depends on how critically you taste.

    So I'll add my own conclusion:
    4) For a cold-extraction, the brew time is so long, uniformity of grind probably doesn't matter a bit. Smashing the beans with a hammer is probably adequate.

    Obviously, the #1 concern of Cory is producing a decent cup with absolute minimum investment of time and suitcase space.

    Suggested test:
    1) Weigh a hotel-provided coffee brewing "beans in a paper sachet". (You'll only have to do this once.)
    2) Multiply by 20/3, and add that many grams/cc of water, and the bag, to a pitcher. Question: Does this fit in the coffee-brewing carafe? I suspect it might!
    3) Wait 12+ hours
    4) Squeeze out the sachet into the pitcher.
    5) Add enough water to double the contents of the carafe.
    6) Drink.

    This would produce cold-brewed coffee that requires ZERO packing.

  5. I can't help thinking, "You use a nut sack to make coffee." I am apparently 36 going on 11 years old.

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