Combine the ground coffee and the water in a mason jar.
1/2 cup ground coffee, 4 cups cold water
Let the coffee steep in the refrigerator for 24 hours.
Strain the coffee using a cheese cloth and a wire mesh strainer.
Serve the cold brew over ice with your favorite coffee accoutrements such as creamer and simple syrup. Please note that granulated sugar won't mix well into the cold brew as it won't have the heat to dissolve.
Video
Notes
Using this ratio, you will get the same amount of caffeine as you would from a typical glass of coffee. Cold Brew Coffee is only more caffeinated when more grounds to water are used.