Follow the ratios and timings suggested in your owner’s manual at first, but feel free to experiment with different variables for your own personal taste. You may find that your water composition or your type of coffee call for slightly different coffee-to-water ratios or brew times for your ideal cold brew. If you are using the KitchenAid Cold Brew Coffee Maker, start with a ratio of nine oz. of coffee to 42 oz. of water for the standard-sized model and brew times ranging from 12 to 24 hours.