I just found this in an Arthur Schwartz column on the net:
Cold-Brewed Coffee Extract Makes about 1 1/2 quarts
1 pound good quality coffee, ground for drip 2 1/2 quarts
cool tap water
In a minimum 3-quart pitcher or jar, combine the coffee and
water. Let stand for 12 hours. Strain the coffee through a
regular kitchen strainer into a 2-quart jar or pitcher.
After the bulk of the coffee Place the strainer over a bowl
for a few hours to get every last drop.
I find that tastes vary about the strength of coffee. For
instance, a guest the other night who was familiar with
coffee extract requested her iced coffee be made with
nothing but the extract, ice, milk and sugar. I needed a
shot of water in mine. For morning coffee, however, I found
that three parts water to one part extract, as the
manufacturer of Suzanne? gadget suggests, was too weak for
me. I preferred two parts.
For Iced Coffee Stir together equal parts of the coffee
extract and cold tap water (or bottled water). Pour over
ice. Add sugar and milk to taste.
For Hot Coffee Use one part coffee extract to 2 to 3 parts
just-boiled water. I just noticed there is a phrase missing
in the middle. Anyway, this has the missing water too--I
guess the grounds soak up a lot.