Coffee is a ratio
The taste of brewed coffee depends mostly on how much coffee you use for a given amount of water. Too little and it tastes thin and bitter; too much and it is heavy and sour. Baristas talk in ratios such as 1:16, meaning 1 gram of coffee for 16 grams of water. Since 1 ml of water weighs 1 g, the math is simple once you weigh your coffee.
Ratios by brewing method
- Drip coffee maker: 1:16. A balanced cup, close to the “golden cup” guideline of about 55 g of coffee per liter of water.
- Pour-over: 1:16 to 1:17. The higher number gives a lighter, tea-like cup.
- French press: 1:15. Immersion brewing with a coarse grind usually tastes better a little stronger.
- Cold brew concentrate: 1:8. Steeped 12 to 24 hours in the refrigerator, then diluted about 1 to 1.
The formulas
- Coffee (g) = water (ml) ÷ ratio
- Level tablespoons ≈ coffee ÷ 5 g; a standard scoop holds 2 tablespoons
- Coffee you get ≈ water − 2 × coffee, because the grounds hold about twice their weight in water
- Caffeine ≈ 7 mg per gram of arabica coffee brewed
Worked example: three mugs
Three 8-oz cups is 710 ml of water. At 1:16:
- Coffee: 710 ÷ 16 = 44.4 g.
- That is about 8.9 level tablespoons, or 4.4 scoops.
- You pour about 21 fl oz of coffee, since the grounds keep around 89 ml.
- Estimated caffeine: 44.4 × 7 = about 311 mg, roughly 100 mg per mug.
Coffee for other amounts at 1:16
| Water | Coffee | Tablespoons |
|---|---|---|
| 1 cup (8 fl oz) | 14.8 g | 3.0 |
| 2 cups | 29.6 g | 5.9 |
| 4 cups | 59.1 g | 11.8 |
| 6 cups | 88.7 g | 17.7 |
| 8 cups | 118.3 g | 23.7 |
Getting the cup you like
- Change one thing at a time. If coffee tastes weak, try 1:15 before buying new beans. If it tastes harsh, try 1:17 or a slightly coarser grind.
- Mind the carafe. The “cups” printed on a coffee maker are usually 5 or 6 fl oz, not 8. A “12-cup” machine holds about 60 fl oz.
- Weigh once, then measure. Scoops vary with grind and roast; weigh one scoop of your coffee to calibrate.
- Caffeine varies. Robusta beans contain about twice as much caffeine as arabica, and dark roasts slightly less by weight. The FDA cites 400 mg a day as an amount not generally associated with negative effects for healthy adults; pregnant people are usually advised to stay much lower.