The right coffee-to-water ratio is very important for a good strong brew. We recommend an absolute minimum of 2.5 ounces of coffee to 64 ounces of water. A good cup of coffee requires a balance of strength and extraction. Strength (amount of coffee soluble solids in water) less that 1% is too weak and greater than 1.5% is too strong. Extraction (amount of soluble solids removed from the ground coffee) is acceptable between 18% and 22%, but extraction below 16% creates a grassy or peanut-like flavor. Extraction above 24% results in bitter astringent flavors.