☕ Specialty Coffee Brew Ratio Calculator
Calculate golden coffee-to-water brewing ratios (1:15 to 1:18) for Pour Over (V60/Chemex), French Press, AeroPress, Cold Brew, and Espresso.
Most recipes sit between 1:15 and 1:17. Higher ratios give a lighter, more tea-like cup. Grind medium-fine, around 2:30–3:30.
Expect roughly 439 g in the cup — wet grounds hold back about two grams of water for every gram of dry coffee, so around 61 g never makes it out of the filter. Brewers who ignore this consistently make less coffee than they planned.
Weigh both, in grams. Scoops and “cups” vary by a factor of two depending on bean density, roast level and grind, which is the single biggest reason a recipe that worked once does not repeat.
The 18–22% extraction and 1.15–1.35% strength targets come from the Golden Cup work that most brewing advice traces back to, along with the often-quoted 55 g per liter. Worth being straight about the sourcing: that figure is not on the Specialty Coffee Association’s current published standards list, and the home-brewer specification that would carry it is members-only, so it is an industry convention here rather than a standard anyone can check. Taste is the arbiter regardless of what the numbers say.
What Specialty Coffee Brew Ratio Calculator Does
A brew ratio is the weight of dry coffee against the weight of water. It is the one variable that changes everything else, and getting it right by weight rather than by scoop is the single biggest improvement most people can make — a level scoop of dense, lightly roasted beans can weigh nearly twice what the same scoop of dark roast does.
The ratio is not the same measurement for espresso. For a brewer, it is coffee to water poured in. For espresso it is dose in to liquid out: 18 grams in the basket producing 36 grams in the cup is a 1:2 ratio, and the machine pushes rather more water than 36 grams through the puck. Calculators that put espresso in the same list as pour-over tell you to use 36 grams of water for an 18 gram dose, which does not make a shot.
What the ratio is really standing in for is extraction — how much of the coffee you actually dissolved. That is measurable, with a refractometer reading and two weights, and the target most brewing advice traces back to is 18 to 22 percent extraction at a strength of 1.15 to 1.35 percent dissolved solids.
One note on sourcing, since every coffee calculator repeats the same figure. The "SCA golden ratio of 55 grams per liter" is an industry convention rather than something you can look up: it is not on the Specialty Coffee Association's current published standards list, and the home-brewer specification that would carry it is behind member login. It is a good starting point. It is not a citable standard, and this page does not pretend otherwise.
How to Use Specialty Coffee Brew Ratio Calculator
- Select your brew method (Pour Over, French Press, AeroPress, Espresso, Cold Brew)
- Enter desired water volume in ml or available coffee beans in grams
- Review exact coffee and water gram weights, grind recommendation, and brew time
Formula Used by Specialty Coffee Brew Ratio Calculator
Ratio, and the extraction it stands in for
water = coffee × ratio extraction yield % = (TDS% ÷ 100 × beverage mass) ÷ dry coffee mass × 100
- TDS%
- total dissolved solids, from a refractometer — the strength of the liquid
- beverage mass
- what ends up in the cup, which is less than the water you poured
- retained water
- wet grounds hold roughly 2 g of water per gram of dry coffee, and it never reaches the cup
Worked example
30 g of coffee at 1:16.5, measuring 1.32% TDS in 440 g of finished coffee.
- Water: 30 × 16.5 = 495 g
- Retained by the grounds: 30 × 2 = 60 g, so about 435 g reaches the cup
- Dissolved solids: 1.32% of 440 g = 5.81 g
- Extraction yield: 5.81 ÷ 30 = 19.4%
Result: 19.4% extraction at 1.32% strength — inside the 18–22% window, and towards the strong end of 1.15–1.35%.
Starting ratios by method
A place to begin, not a rule. Every one of these has a usable range around it.
| Method | Ratio | Grams per liter | Grind |
|---|---|---|---|
| Pour over | 1:16.5 | 61 g | Medium-fine |
| Batch / drip machine | 1:17 | 59 g | Medium |
| French press | 1:15 | 67 g | Coarse |
| AeroPress | 1:13 | 77 g | Medium-fine |
| Moka pot | 1:10 | 100 g | Fine-medium |
| Cold brew concentrate | 1:5 | 200 g | Extra coarse |
Espresso, which is a different measurement
Dose in to liquid out, not coffee to water.
| Style | Ratio | From an 18 g dose |
|---|---|---|
| Ristretto | 1:1.5 | 27 g out |
| Normale | 1:2 | 36 g out |
| Lungo | 1:3 | 54 g out |
Reading a bad cup
Strength and extraction are independent. A cup can be weak and over-extracted at once, which is why changing the ratio alone often fails.
| Tastes | Usually means | Try |
|---|---|---|
| Sour, thin, salty | Under-extracted (below 18%) | Grind finer, brew longer, or use hotter water |
| Bitter, drying, hollow | Over-extracted (above 22%) | Grind coarser, brew shorter, or use cooler water |
| Balanced but watery | Correct extraction, too little coffee | Tighten the ratio — less water per gram |
| Balanced but overwhelming | Correct extraction, too much coffee | Widen the ratio |
How to Read Your Result
Weigh everything, in grams
Water at brewing temperatures is close enough to 1 g per ml that you can use either, but coffee absolutely must be weighed. Scoops and "cups" vary by a factor of two with bean density, roast level and grind, and that is the most common reason a recipe that worked once does not repeat.
You will get less coffee than you poured water
The grounds keep roughly two grams of water per gram of dry coffee. Brewing with 500 g of water and 30 g of coffee leaves about 440 g in the cup, not 500. Recipes written for a specific carafe volume have to account for it.
Change one thing at a time
Grind size, ratio, water temperature, brew time and agitation all move extraction. Changing two together makes the result uninterpretable, which is how people end up convinced their coffee is random.
The numbers serve the taste, not the reverse
The 18–22% window describes what most people preferred in the experiments behind it, not a law. Plenty of excellent coffee sits outside it, particularly with lighter roasts and unusual processing. If you like it, it is right.
Limitations & Accuracy Notes
- Ratios are starting points. Bean origin, roast level, grind distribution, water chemistry and temperature all shift the result substantially.
- The "55 g per liter" convention cannot be verified against a publicly available SCA document, as described above.
- Extraction yield here assumes you have measured TDS with a refractometer; without one, the ratio is only a proxy.
- The 2 g per gram retained-water figure is an approximation that varies with brewer, grind and how the bed is drained.
- Espresso yield in the cup is not the same as water through the puck, and this does not model the difference.
- Water treated as 1 g per ml, which is accurate enough for brewing and not exactly true at temperature.
Frequently Asked Questions
What is the golden ratio for pour over coffee?
Why is brewing water measured in grams?
What ratio should I start with?
Should I measure by weight or by scoop?
What is the difference between ratio and strength?
Why does my coffee taste sour or bitter?
Does water matter?
Is my data stored?
References & Further Reading
- Specialty Coffee Association — published standards — The current standards list, checked directly — note that no public brewing-ratio standard appears on it