The amount of water you put in a 6-cup Chemex, if you’re making a full pot, should be just about 1 litre. This yields plenty of coffee for 2-3 people – about four 240-ml cups. And if you’re using the “golden ratio,” this makes the math easy: grind 55g (about 2 ounces) of coffee for 1 litre of water and you’re, well, golden.