"Matthew Yglesias at the Internet Food Association blog writes that it's really a matter of overnight cold-brewing and straining. First, gather up 1 cup of coarse-ground and stir it into 4 1/2 cups of water, or strengthen the mix to taste. After that 'stick it in the fridge for, ideally, a 12 hour overnight brew. In the morning, strain the mixture. If your strainer isn't fine-meshed enough (mine isn't) you can supplement it with a paper coffee filter. Now you've got a delicious pitcher of coffee concentrate. Pour some over an ice cube and enjoy!' "
I'ma try it this weekend and let you know how it goes.