Coffee to Water Ratio Calculator

Why the ratio matters

Coffee's flavor compounds — acids, sugars, bitter elements — extract into water at different rates. The coffee-to-water ratio directly controls concentration: too little coffee produces weak, under-extracted flavor; too much produces bitterness from over-extraction. Getting the ratio right is step one; grind size and temperature are step two.

Brew ratio = Water (g) / Coffee (g)

1:15 means 15g water per 1g coffee. For 300ml yield: 20g coffee + 300ml water.

Standard ratios by method

Pour-over: 1:14–16. The SCA Golden Cup targets 1:15.6. Light roasts → 1:14–15; dark roasts → 1:16–17.
French press: 1:12–15. Full-immersion is slightly more efficient, so slightly less coffee needed.
Espresso: 1:1.5–2.5. Classic double: 18–20g in, 36–40g out, 25–30 seconds. Lighter roasts can go to 1:3+ (lungo).
Cold brew concentrate: 1:4–6. Steep 12–24h cold. Dilute 1:1 before serving.
AeroPress: 1:10–16. Highly versatile — shorter steep and finer grind allows stronger ratios.

Always measure by weight

A scoop of coffee can vary 15–25% in weight depending on grind size and packing. A $15 kitchen scale transforms your consistency immediately. For water, 1ml = 1g, so volume works fine.

Water quality

Coffee is ~98% water. Minerals aid extraction — magnesium enhances floral and fruity notes; alkalinity suppresses acidity. Distilled water makes flat coffee. Filtered tap water at 50–200 ppm TDS is ideal for most setups.

Frequently Asked Questions

Should I measure coffee by weight or volume?

Always by weight. A scoop of coffee can vary 15–25% depending on grind size and packing. A kitchen scale (even a cheap one) makes an immediate, noticeable difference in cup-to-cup consistency.

My coffee tastes sour or bitter — what should I change?

Sour (under-extracted): try a finer grind before adjusting ratio — grind is the primary lever. Bitter (over-extracted): try coarser grind first. Adjust one variable at a time. If grind is already dialed in, then adjust ratio: more coffee for sour, less for bitter.

Does the ratio change for different roast levels?

Yes. Lighter roasts are denser and extract more slowly — often taste better at 1:14–15 or with a finer grind. Darker roasts are porous and extract faster — often better at 1:16–17 to avoid bitterness. Dial in each new bag individually.

What temperature should the water be?

90–96°C (195–205°F) for most filter methods. Espresso: 90–94°C. Cold brew uses cold water but compensates with a much longer steep time (12–24 hours). Water that's too cool under-extracts; too hot can over-extract dark roasts.