And... once you've made your jar and put it in the fridge, how long is it good for would you say?
The mason jar I use came with the conical filter. It holds 6 cups, so it's like a quart + a pint. The cafe owner who turned me on to this stuff makes her cold brew with a big cheesecloth bag and a 5-gallon bucket. If you search online you can find all sorts of devices for making cold brew, most much smaller than my 6-cup jar. But you don't really need fancy equipment. A container and some kind of filtering system is all you need. You could even use one of those French press coffee makers. The only question would then be the ratio of coffee grinds to water, and I'm sure that information is available online.
And remember to use coarsely ground beans. Pre-ground beans are way too fine. Also, apparently, those cheap coffee grinders that actually cut the beans up are no good. The beans have to be actually ground (don't ask me why), which is why I got a cheap hand-grinder.
How long will the coffee last in the fridge? Good question. I don't know for sure. I usually pour the coffee out of the big mason jar into smaller mason jars so that my wife can take one to work if she wishes. My sense is that they could last a long time sealed in those jars in the fridge. When I pour the coffee from the big mason jar there is some sediment at the bottom that makes the last 1/2 inch or so unusable. I just dump that.
Dusty T., Northern California
As a musician, you have to keep one foot back in the past and one foot forward into the future.
-- Dizzy Gillespie
updated by @dusty-turtle: 06/22/18 01:28:02PM