The proportions we use here are the same as discussed above. We’ll use a 1:15 coffee grounds-to-water ratio, though again, that’s only our starting recommendation. Other coffee lovers commonly use 1:18 ratios, for example.
The important thing to remember here is that a 3 cup Chemex doesn’t really equal 3 cups of coffee (well, it can, but it depends on how small you like your cups of coffee). We find that a 3 cup Chemex really only makes around 1 to 2 cups of coffee. A 6 cup Chemex coffee maker, on the other hand, maxes out around 3 to 4 cups.
By that mark, we’ll take 25 grams of coffee grounds and 375 grams of water (13.2 oz), to start off with our 3 cup Chemex carafe. Alternatively, 25 grams coffee and 375 grams (13.2 oz) of water is another decent starting amount.