Ratio, grind and time
The brew ratio explained, with a calculator, plus how grind size, water temperature and brew time work together and how to fix a cup that tastes sour or bitter.
The brew ratio
The ratio is how much water you use for each gram of coffee. At 1:16, 15 g of coffee takes 240 g of water. It sets how strong the cup is, so it's the first thing to get right and the easiest to repeat: weigh both, rather than measuring with scoops, since a scoop of a light roast weighs more than a scoop of a dark one.
Most filter recipes land between 1:15 and 1:17. Immersion brewers like the French press often go a little stronger. Espresso counts differently: its ratio is coffee in to drink out, usually around 1:2.
| Method | Ratio | For example |
|---|---|---|
| Pour-over (V60, Kalita, Chemex) | 1:15 to 1:17 | 15 g coffee, 250 g water |
| AeroPress | 1:12 to 1:16 | 15 g coffee, 200 g water |
| French press | 1:12 to 1:16 | 30 g coffee, 500 g water |
| Espresso | 1:2 to 1:2.5 (out) | 18 g coffee, 36 to 45 g espresso |
| Cold brew concentrate | 1:5 to 1:8 | 100 g coffee, 700 g water, diluted to serve |
Grind, temperature and time
Brewing dissolves flavor out of the grounds, and three things control how much: finer grounds extract faster because there's more surface; hotter water extracts faster; and more time extracts more. Too little extraction tastes sour and thin, too much tastes bitter and dry.
Grind size and time work as a pair. Fine grinds suit short brews (espresso, about 30 seconds); coarse grinds suit long ones (French press, four minutes or more). In a pour-over, a finer grind also slows the water down, so grinding finer makes the brew take longer.
Water just off the boil, around 92 to 96 °C (198 to 205 °F), suits most light and medium roasts. Darker roasts extract easily and can taste harsh that hot; try 85 to 90 °C.
Dialing in by taste
Change one thing at a time, and change grind first: it has the biggest effect. Make a note of what you changed so you can go back.
- Sour, sharp, thin
- Under-extracted. Grind finer, use hotter water, or brew longer.
- Bitter, dry, harsh
- Over-extracted. Grind coarser, use slightly cooler water, or brew shorter.
- Weak but pleasant
- The extraction is fine; the cup is just dilute. Use more coffee for the same water (1:15 instead of 1:17).
- Heavy and muddy
- Too strong. Use a little less coffee for the same water.
- Fine yesterday, off today
- Coffee changes as it ages, and a very fresh bag can taste sharp for a few days. Resting coffee after roasting