What a ratio means
A ratio is the weight of coffee against the weight of water. 1:16 means one gram of coffee for every 16 grams of water. Double the coffee and double the water, and the cup tastes the same. Measure both in grams on a kitchen scale.
What the SCA Golden Cup says
The Specialty Coffee Association's Golden Cup standard is 55 grams of coffee per litre. It allows 10 percent either way, so roughly 50 to 60 grams. 55 grams per litre is about 1:18. Many sites loosely give a range of 1:16 to 1:18. Strictly, 1:16 is about 62 grams per litre, just outside the allowed range. The standard covers filter brewing only; espresso and cold brew play by other rules.
Why each method has its own ratio
Each method makes a different kind of drink, and the ratio follows. Espresso is a small, concentrated shot, pulled in about 30 seconds. Pour over and drip are drunk as they come, with far more water. Cold brew concentrate is made strong on purpose. You dilute it with about the same amount of water before drinking. It steeps in cold or room-temperature water, usually somewhere between 8 and 24 hours.
| Espresso | Moka pot | Pour over | French press | Drip machine | Cold brew concentrate | Turkish coffee | |
|---|---|---|---|---|---|---|---|
| Coffee to water | About 1 : 2 | About 1 : 7-10 | About 1 : 15-17 | About 1 : 12-18 | About 1 : 17-18 | About 1 : 4-8, then dilute about 1 : 1 | About 1 : 10 |
| For example | 18 g in, 36 g out | 15-17 g, water to the valve | 15 g to 250 g | 30 g to 500 g | 55 g per litre | 340 g to 1.9 L | 7 g to 70 ml |
Why a scale beats a scoop
A tablespoon of dark roast weighs about 5 grams; a light roast, up to 7. The scoop in your coffee maker's box is often two tablespoons. One 12-cup drip machine counts a cup as 5 ounces, about 148 ml. A US measuring cup is 8 ounces. A French press cup is about 4. A kitchen scale skips the guesswork. Weigh the coffee and the water, to the nearest gram.
Adjusting to your taste
Ratio mostly changes strength, so more coffee or less water makes a stronger cup. Extraction is how much of the grounds ends up in the water. Finer grounds, a longer brew or hotter water all pull out more. In 2023, UC Davis and the SCA found coffee drinkers split into two taste groups. Each group likes a different strength, so there is no single right one.