In a large glass container, gently stir coffee grounds into water.
Cover and allow the mixture to sit at room temperature for 8 to 16 hours. NOTE: The longer the mixture sits, the stronger the resulting coffee concentrate.
Pour mixture through the strainer lined with a coffee filter or cheesecloth into serving jug. You may want to strain the coffee twice to remove as much sediment as possible.
The result is a concentrated solution, so mix with equal parts cool water.