Coarsely grind the coffee beans using your preferred method. I used a food processor on high for about 1 - 2 minutes.
Pour the water and the coffee into a large, air-tight container and stir to mix in the coffee grounds. Cover and place in a cool, dry place for at least 12 hours, and up to 24 hours. The longer it brews, the stronger it will be, but don't exceed 24 hours.
Strain out the coffee beans using a fine mesh strainer double lined with coffee filters.