Place 1 ½ cups of ground coffee (course ground coffee is a bit easier to strain) into a large glass container. Add 8 cups water and stir until completely incorporated.
Screw the top on the container or cover with a towel.
Let the coffee and water mixture sit on the counter at room temperature for at least 12 hours (can go up to 24 hours).
Place a small funnel and strainer firmly into a glass carafe. Cut a square of cheesecloth and place it into the funnel over the strainer. Slowly pour the coffee concentrate into the funnel a little at a time (this process takes a few minutes). Continue until carafe is full.
Repeat with second glass carafe if desired or use the remaining concentrate to make coffee ice cubes.
Pour remaining coffee concentrate into ice cube tray and freeze.
Place the glass carafe(s) full of the coffee into the fridge and chill until cold.
To serve: Place coffee ice cubes, chilled coffee, desired amount of milk, and 1 tsp. sugar (optional) in glass and stir.
Notes
Recipe may be doubled for larger amount.Make sure to cover chilled coffee in fridge with some type of lid.Discard the coffee grounds when finished or use them as compost in your garden!