Grind coffee beans into a coarse grind. Place into a large pitcher. Add water and stir. Cover with plastic wrap or a cheesecloth and let sit at room temperature for 8 hours.
Line a fine mesh strainer with a cheesecloth or coffee filter and strain cold brew. Discard solids. Pour ½ cup cold brew over ice and stir in ¼ cup of water. Add additional water or milk as desired.