So yesterday I splurged on the most expensive coffee I've ever purchased, $14.20 per pound. I bought 1/2 pound coarsely ground. Wow does the house smell great!
12 oz cold filtered water, 11 grams coffee, steep for 12 hours in airtight container. I gave it a couple shakes along the way. I then filtered it through a paper drip filter, added 100 grams of unsweetened almond milk.
It's very good, barely a hint of bitterness, which may simply be the result of the long steeping time. Recommendations go from 6 to 12 hours and mine was probably 13 hours, but it is very good.
Caffeine relieves pain, which is scientific fact. Caffeine and coffee also bring on IBS symptoms in yours truly and I wish to find out if the reduced acidity in cold brew can allow me to have a bit of pain relief and the health benefits that come with coffee consumption.
My recipe is half strength of recommended, IOW twice the water. I also had to confess my behavior to my wife with whom I've had a pact for the past 12 years that I would not drink coffee. But she is okay with my plan.
You may also find that acidity varies from region to region. IIRC, Central and South American beans tend to be less acidic, African ones more.