For a smoother, more flavorful iced coffee, start with a homemade cold-brew concentrate.
Stir together ground coffee and 8 cups cool water. Cover; let stand at room temperature 24 hours. Strain through a coffee filter or cheesecloth-lined sieve into a container, pressing on the solids to remove as much liquid as possible. Store in the refrigerator, covered. One batch makes a week's supply. Dilute 1 part concentrate with 1 to 2 parts cold water or milk; sweeten as desired and serve over ice.