Place the coffee grounds in a 2-quart pitcher, add the water, and stir to combine. Cover with plastic wrap and let steep at room temperature for at least 12 hours and up to 1 day.

Line a fine-mesh strainer with a standard coffee filter and fit it over a medium bowl. Working in batches, slowly pour the coffee into the filter until all of the liquid has passed through the strainer (the coffee will pass through in a slow stream; don?t force it through); stop when you reach the solids at the bottom of the pitcher (don?t pour them in). Discard the grounds and the contents of the strainer.

Wash and dry the pitcher. Transfer the strained coffee into the pitcher. Cover and refrigerate until completely chilled, at least 2 hours or up to 5 days.

For each cup of iced coffee, dilute the concentrate with an equal portion of milk, half-and-half, or water. Sweeten with simple syrup if desired and top with ice.