Coarsely grind 1 cup of coffee beans
Add the grounds to a jar or pitcher
Pour in 4 cups of cold, filtered water
Stir gently to wet all the grounds
Cover and steep in the refrigerator or at room temperature for 12 to 18 hours
Strain through a fine mesh sieve, cheesecloth, or coffee filter
Discard the grounds
Store the concentrate in a sealed container in the refrigerator
Dilute with equal parts water or milk before serving, or adjust to taste