Place coarsely ground coffee beans in a large container.

Gradually add 7 cups of cold water.

Stir gently to ensure all coffee grounds are moistened.

Cover the container with a layer of cheesecloth.

Let the mixture stand at room temperature for 15 hours to infuse.

Remove the cheesecloth.

Line a fine-mesh sieve with cheesecloth and set it over a large pitcher.

Pour the coffee through the sieve into the pitcher, being careful not to stir.

Rinse the original jar and set it aside.

Discard the used cheesecloth and coffee solids.

Line the same sieve with a large coffee filter and set it over the reserved jar.

Strain the coffee through the filter into the jar, allowing it to drip through naturally (this may take up to 45 minutes).

Avoid stirring the coffee during straining to prevent cloudiness.

Cover the jar and chill the coffee concentrate.

Fill a glass with ice.

Dilute the coffee concentrate with an equal part of milk (if desired) or water to your taste.

Serve immediately.