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Coffee brew ratios: grams, water and taste

A brew ratio is the weight of coffee compared with the weight of water. It is the most repeatable way to change strength without guessing at scoops.

Written and reviewed by SM Arijul Islam · Last reviewed 23 October 2026 · Editorial standards · Report an error

Start with weight

Coffee is porous and settles at different densities. A tablespoon of fine grind can weigh nearly twice as much as a tablespoon of coarse grind. Weighing both coffee and water removes that variable. In practice, 1 g of water is 1 mL, so a scale is also a volume measure.

Use a scale that reads to 0.1 g for doses under 30 g. A 0.1 g error on an 18 g dose is 0.6%; the same error on a 5 g espresso dose is 2%.

The ratio formula

Ratio = water ÷ coffee. A 1:16 ratio means 16 g of water for every 1 g of coffee. For an 18 g dose, water = 18 × 16 = 288 g. For a 250 g cup at 1:16, dose = 250 ÷ 16 = 15.6 g.

Brewed yield is not the same as water. The bed retains about 2 g of water per gram of dry coffee. An 18 g dose with 288 g of water yields about 252 g in the cup. If you want 250 g out at 1:16, start with about 17.9 g coffee and 286 g water, not 15.6 g.

Ratio sets strength, extraction sets flavour

Ratio controls strength; grind, time and temperature control extraction. A 1:15 brew is stronger than a 1:18 brew made the same way, but it is not necessarily more extracted. If a coffee tastes weak and sour, it may be under-extracted rather than under-dosed. If it tastes weak and bitter, it may be over-extracted.

Use ratio as a deliberate variable. Change one thing at a time: dose, then ratio, then grind.

Filter-coffee ratios for an 18 g dose
Ratio	Water	Approx. yield	Style
1:12	216 g	180 g	Very strong; concentrate or immersion
1:14	252 g	216 g	Strong
1:15	270 g	234 g	Strong, common starting point
1:16	288 g	252 g	Balanced
1:17	306 g	270 g	Lighter
1:18	324 g	288 g	Light and tea-like
1:20	360 g	324 g	Very light

Approximate yield assumes about 2 g of water retained per gram of coffee. A finer grind or a taller bed can retain more.

Method starting points

Typical brew ratios by method
Method	Typical ratio	Notes
Espresso	1:2 (yield)	18 g in, about 36 g out, in 25–30 s
Moka pot	1:10	Approximate; steam and bypass make it variable
AeroPress	1:12–1:16	Depends on steep time and dilution
V60 / pour-over	1:15–1:17	Adjust grind for drawdown time
French press	1:15–1:17	Full immersion, then press and decant
Drip machine	1:16–1:18	Check the basket size and hotplate
Cold brew	1:8–1:12	Concentrate; dilute to taste before serving

Espresso is the exception: its ratio is brewed yield divided by dry dose, not water poured. A 1:2 espresso is 18 g in and 36 g out. The water in the boiler is not part of the recipe.

Extraction yield

Extraction yield (EY) is the share of the dry coffee mass that dissolves into the cup: EY = TDS × beverage mass ÷ dose. For an 18 g dose, 252 g beverage and 1.35% TDS, EY = 0.0135 × 252 ÷ 18 = 18.9%.

Specialty coffee often targets 18–22% EY, but taste is the final judge. A 1.35% TDS at 1:16 is a typical filter-strength cup. Espresso is much more concentrated, usually 8–12% TDS.

Coffee TDS is measured with a refractometer, not the conductivity meter used for water hardness. A generic TDS pen will not give a meaningful coffee reading; use a coffee-specific refractometer and its conversion model.

Adjusting by taste

What to change when the cup is not right
What you taste	Likely cause	First change
Sour, thin, salty	Under-extracted	Finer grind, hotter water, longer contact
Bitter, dry, ashy	Over-extracted	Coarser grind, cooler water, shorter contact
Weak but sour	Under-extracted at a high ratio	Tighten the ratio slightly, then grind finer
Strong but bitter	Over-extracted at a low ratio	Loosen the ratio, then grind coarser
Muddy, slow drawdown	Too fine or too many fines	Coarser grind; improve the grinder or sieve
Hollow, watery	Channeling or low dose	Improve distribution, then increase dose

Water and temperature

Brew water around 90–96 °C. Lighter roasts usually take the higher end; dark roasts the lower. Water chemistry matters too: very soft water can taste flat, very hard water can mute acidity. A simple starting point is 50–175 ppm hardness as CaCO₃ and 40–70 ppm alkalinity, but this is a style choice.

Do not use distilled water alone for brewing; it lacks the minerals that help extraction. If you use zero-TDS water, add a mineral buffer.

Scaling a brew

To scale a brew, keep the ratio and change both numbers. Doubling water without doubling coffee makes a weaker cup, not more coffee. To fill a 1 L server at 1:16, use 62.5 g coffee and 1,000 g water; expect about 875 g in the server after retention.

For batch brewing, keep the bed depth and contact time in mind. A larger batch in the same basket may need a coarser grind or a longer brew.

Frequently asked questions

What is the golden ratio for coffee?

Most filter coffee sits between 1:15 and 1:18 by weight, with 1:16 a common starting point. Espresso is much tighter, typically 1:2 brewed yield to dry dose.

Is a coffee cup 250 mL?

A US customary cup is about 240 mL and a metric cup is 250 mL. Weighing the water avoids the difference entirely.

Why does my coffee taste weak even at 1:15?

Ratio only sets strength. A weak, sour cup is often under-extracted, so grind finer, raise the temperature or extend the contact time before adding more coffee.

Should I use the same ratio for espresso?

No. Espresso is usually 1:2 by brewed yield, not 1:15 by water poured. The same arithmetic applies but the measured output is different.

Does the ratio include water left in the grounds?

No. The ratio uses water poured. Brewed yield is lower by roughly 2 g of water per gram of dry coffee.

Can I use tablespoons instead of a scale?

Yes, but calibrate the spoon against a scale for your grind. A tablespoon of fine coffee can weigh nearly twice as much as a tablespoon of coarse coffee.

Sources

Specialty Coffee Association — brewing standards and best-practice guidance.
Scott Rao, The Professional Barista's Handbook — extraction yield and brew ratio.
James Hoffmann, The World Atlas of Coffee — method ratios and water guidance.
SCA water quality guidance for brewed coffee.