Cold-brewed concentrate is common in New Orleans (not so much here in NC). It's easy to make, and you just keep it in the fridge for a quick iced coffee (add water or milk.) Mmm. We make it with the Cafe du Monde coffee/chicory blend, in a big stainless cookpot, and keep the concentrate in a nalgene bottle. Not sure how much water to add -- I'll check when I get home. I drink this all summer long.

Oh, and you filter it (twice) through a fine strainer, NOT a coffee filter -- takes too much of the flavor out. There is some sediment in the bottom of the bottle at the end.