If you're using a commercial cold-brew maker like a Toddy, follow the manufacturer's instructions for mixing and filtering. Feel free to play around with how you dilute this—you might prefer a stronger or weaker coffee than the one suggested here. And coffee-heads the world over agree: cold-brew is only as good as the beans it's made with.

12 ounces high-quality coffee beans (about 4 cups), coarsely ground

Milk (optional; for serving)

A 12-cup (or larger) resealable container or stockpot with lid; a coffee filter or cheesecloth

Preparation Place ground coffee in 12-cup container. Slowly pour 6 cups cool water over grounds. Stir very gently just until grounds are moistened. Seal container and chill 24 hours. Strain coffee grounds through a fine-mesh sieve into a large measuring cup or bowl. Strain again through coffee filter into a large bowl or 3-cup (or larger) resealable container. (Alternately, skip the straining and use a thick filter, like for a Chemex.) To serve, pour over ice and dilute 1:1 with water or milk.