The coffee golden ratio is 55 g of coffee per liter of water, plus or minus 10 percent, as set out in the Specialty Coffee Association's Golden Cup standard. By weight that's about 1:18, and the 10 percent window stretches from roughly 1:16.5 to 1:20.
| Water | Coffee at 55 g per liter | Golden Cup range |
|---|---|---|
| 250 ml | 13.8 g | 12.4 to 15.1 g |
| 350 ml | 19.3 g | 17.3 to 21.2 g |
| 500 ml | 27.5 g | 24.8 to 30.3 g |
| 1 liter | 55 g | 49.5 to 60.5 g |
| 1.5 liters | 82.5 g | 74.3 to 90.8 g |
Where the coffee golden ratio comes from
The SCA's Golden Cup guidelines are a set of brewing targets, and the ratio is just one part. The full list looks like this:
- Ratio: 55 g per liter, plus or minus 10 percent (49.5 to 60.5 g per liter).
- Water temperature: 200°F, plus or minus 5°F (93°C, plus or minus 3°C) where it meets the coffee.
- Contact time by grind: 1 to 4 minutes for a fine grind, 4 to 6 minutes for a drip grind, 6 to 8 minutes for a coarse grind.
Even the SCA's cupping protocol lines up with it. Cuppers use 8.25 g of coffee per 150 ml of water, which works out to the same 55 g per liter.
Strength and extraction: the numbers behind the ratio
The ratio exists to hit two targets in the cup. Moccamaster, quoting the SCA standard, puts brew strength at 11.5 to 13.5 g of dissolved coffee per liter, which shows up on the SCA Brewing Control Chart as 1.15 to 1.35 percent. The extraction yield target is 18 to 22 percent, meaning that share of the dry coffee's weight ends up dissolved in your cup.
You don't need a refractometer to use any of this. The point is simple: if you hold the ratio steady, you can trust that changes in taste are coming from grind, water or beans, not from a random scoop.
Why your own ratio might be different
The golden ratio is a target, not a rule. Plenty of good coffee is brewed outside it. Clive Coffee gives 1:15 to 1:17 as a typical filter range, which is a bit stronger than the SCA middle. Roast level, grind, brewer and simple taste all play a part.
A good way to think about it:
- Start at 1:18 (55 g per liter) if you want the classic balanced cup.
- Move toward 1:16 if it tastes thin or watery.
- Move toward 1:20 if it tastes heavy or too intense.
Espresso is a different world. Its ratios run closer to 1:2, so the golden ratio is for brewed coffee like drip, pour over and French press.
How to brew at 55 g per liter
- Decide how much water you're brewing. 1 ml of water weighs about 1 g, so 500 ml is about 500 g.
- Multiply by 0.055. For 500 ml, that's 27.5 g of coffee.
- Weigh the beans, then grind to suit your brewer.
- Heat water to about 200°F (93°C).
- Brew, then taste. If you change something, change only one variable at a time.
Want more on getting your dose consistent? Our guide to measuring coffee grounds walks through it.
A practical tip: golden ratio doses are rarely round numbers, and 13.8 g or 19.3 g is hard to hit with a scoop. The MeasureMate digital measuring spoon scoops and weighs in one step, with a display that reads in 0.1 g steps. Press tare to zero it between scoops.
Quick questions
Is the golden ratio 1:15 or 1:18?
The SCA figure, 55 g per liter, is about 1:18. Ratios like 1:15 and 1:16 are popular stronger choices that sit a little above the SCA's 10 percent window, which tops out near 1:16.5.
Does the golden ratio apply to espresso?
No. Espresso is brewed far more concentrated, usually around 1:2 coffee to liquid espresso.
Should I measure water in ml or grams?
Either works, since 1 ml of water weighs about 1 g. Grams are easier if your scale is already out.
Ratios based on the Specialty Coffee Association Golden Cup standard and cupping protocol, Moccamaster and Clive Coffee.