let it cold brew on the counter 24 hours, filter it through a coffee filter , and it keeps in the fridge. Mix with equal amount of water, microwave fo r 90 seconds, and I have a cup of much better tasting coffee than I can get with the other methods.
I looked at a lot of sites before I tried this.
The amounts varied a bit, but basically converged on 1 part coffee to 4 par ts water if you measure by volume, 1 part coffee to 8 parts water if you me asure by weight.
After a little experimenting I standardized on 10 scoops of coffee into the jar and fill it up with water. This is a standard coffee scoop supposed t o make one cup. It holds 7 g of coffee if you're into metric. I stir it, wait for the bloom (that crust that forms on top), stir it again, and close the jar until time to filter.
Filtering is a bit of a pain because the grounds clog the filter. There's probably a better way but I just use a Melitta pour-over filter.
This makes concentrate, you want to dilute it 50/50 with water when you mak e it. It will keep a couple weeks in the refrigerator without a decline in quality.