In a large vessel, mix coffee beans and cocoa powder. Pour in water, stirring so all grounds are fully moistened.
Cover tightly with saran wrap, then poke a holes in the top to allow air to escape. Place in fridge for at least 12 hours (overnight works great).
Once steeped, strain the coffee over a cheesecloth into a second large vessel. Squeeze the coffee grounds to remove all liquid. Throw away used grounds, then repeat process again, straining out any additional sediment (this makes the difference between murky and clear coffee!). Place into an air-tight container, keeping refrigerated until ready to use. Will last 5 days in fridge!
Note: This will make about 7 cups of coffee concentrate. When you’re ready to drink it, pour it over ice, then add the same amount of water. This will dilute your coffee to the proper level, otherwise you’ll get a huge caffeine buzz!