Put the coffee grounds in a pitcher or other large glass container, like a 1-quart mason jar. Add 2 cups cold filtered water. Stir to make sure the grounds are fully saturated. Cover and let sit at room temperature for at least 12 and up to 24 hours. Give it a taste periodically to see if it is strong enough for you; when it is, you’re ready for Step 2.
Line a fine-meshed strainer with 2 layers of dampened cheesecloth and set it over a bowl. Very slowly pour the coffee and grounds into the strainer. Let the coffee fully drain into the bowl. Transfer the coffee to a clean pitcher or airtight glass container and refrigerate until cold before enjoying over ice.