I mostly drink iced coffee so I switched to cold-brew … this is the “recipe” I started with and am in the “evolutionary” stage with the process. I've discovered that the ratio of ground coffee to water in my “extractor” is too high when I follow this so I've revised to 4 oz (weight) of coffee – finely ground in my 12 cup press and fill to the “band” … otherwise I'm getting too strong an extraction.
The place I started was http://www.americastestkitchenfeed.com/do-it-yourself/2011/08/how-to-make-cold-brew-coffee/ and they have a great “starting place” recipe.
Makes about 2 cups of coffee concentrate
I like to make cold-brew with a medium roast, as I find it tastes more like coffee and less like the roasting process than dark or French roast. Light roasts tend to be too acidic. As with any kind of coffee brewing, it’s best to grind the beans yourself just before using them. The ratio of water to coffee is 1:1 by volume and roughly 4:1 by weight, so feel free to scale the recipe to suit your needs. If you don’t have a French press you can make the coffee in a pitcher and strain it through a fine-mesh strainer, and finally through a coffee filter, as in step 2.
3½ cups finely ground medium roast coffee (see note)
Kosher salt (optional)
1. Stir together coffee and 3½ cups room-temperature water in large French press. Allow raft of ground coffee to form, about 10 minutes, and stir again to incorporate. Cover with plastic wrap and let sit at room temperature for 24 hours (an hour shorter or longer is fine).
2. Using French press plunger, press firmly on grinds to separate them from concentrate. Pour coffee concentrate into coffee filter-lined fine-mesh strainer set over large measuring cup. Let sit until concentrate filters through, up to 30 minutes. (You should have about 2 cups of coffee concentrate; concentrate can be covered and refrigerated for up to 3 days).
3. Combine ½ cup coffee concentrate, ½ cup cold water, and pinch Kosher salt (if using) and pour into glass with ice. Drink.
Following their recipe I used about 4 to 1 of water to extract and use the pink salt grinder for a touch at the top.
My next phase is to have the coffee ground by our local Starbucks when I purchase it and use my new ratio of 4 oz coffee to a filled press pot. I'll keep you posted on results and in the mean time you can go and do your own testing and see how you like it.