- Measure out the water and coffee grounds at a ratio of eight to one by weight. For example, if you use 2 cups of water, then you'll need about 4.5 tablespoons of coffee.
- Mix the water and coffee grounds in the container and stir them to make sure water saturates all the grounds.
- Cover the container and let it sit at room temperature for 18 to 20 hours.
- Remove the grounds from the coffee by pouring the mixture through the filter. If there are still grounds in the coffee after the first round, you may need to repeat this filtration process. (The next time you try this process, consider using a finer filter or coarser coffee grounds, which will be easier to remove.)
- Serve chilled or on ice, with milk and sugar if you prefer.
- Store your leftover cold brew in the fridge, where it can last up to fourteen days.