Coffee-to-Water Ratio Calculator

Ratio	Coffee per L water	Profile
1:15 (SCA)	67 g/L	Balanced
1:13 (strong)	77 g/L	Balanced
1:17 (light)	59 g/L	Light

The SCA Golden Ratio

The Specialty Coffee Association (SCA) recommends 55–65 g of coffee per litre of water (1:15 to 1:18) as the 'golden ratio' for filter coffee. This range produces a Total Dissolved Solids (TDS) of 1.15–1.35%, which the SCA has identified as the ideal extraction strength based on thousands of tasting evaluations.

The golden ratio is a starting point, not a rule. Taste is subjective and depends on the specific bean, roast level, grind size, water temperature, and brew time. The ratio only controls the concentration — extraction quality depends on technique.

Espresso vs filter coffee ratios

Espresso uses a dramatically different ratio (1:2) under high pressure (9 bar). A standard double shot extracts 36 g of espresso from 18 g of coffee in 25–30 seconds. The high pressure forces water through finely ground coffee, extracting flavor compounds much faster than gravity-fed methods.

Cold brew uses the opposite extreme: a long steep (12–24 hours) at room temperature or in the fridge, with a high coffee:water ratio (1:5 to 1:8 for concentrate). The cold temperature extracts different flavor compounds than hot water, producing a smooth, low-acidity concentrate that you dilute 1:1 to 1:3 before drinking.

Ratios by Brew Method

Each brew method extracts coffee differently — pressure, immersion time, filter type, and grind size all interact with the ratio to determine the final cup.

Drip / Filter (SCA Golden Cup): 55 g/L (1:18.2), the SCA baseline for a balanced brew with 1.15–1.35% TDS
Pour over (V60, Chemex): 1:15 to 1:17 (stronger to balanced)
French Press: 1:12 to 1:15 — heavier body due to no paper filter; metal mesh lets oils and fine particles through
Espresso: 1:2 to 1:3 by weight (e.g., 18 g coffee → 36–54 g espresso shot) under 9 bar pressure
Cold brew: 1:5 to 1:8 for concentrate (steep 12–24 h), then dilute 1:1 to 1:2 to serve
AeroPress: 1:10 to 1:16 depending on style — espresso-style (1:10) vs filter-style (1:14–1:16)
Moka pot: ~1:7 — very concentrated, similar to strong espresso; meant to be diluted with water or milk

Limitations — What Ratio Doesn't Control

The ratio sets the concentration framework, but it cannot compensate for these variables:

Grind size: Has more impact on extraction than ratio. A 1:15 ratio with too coarse a grind will be under-extracted — sour and thin — regardless of dose.
Water temperature: 90–96 °C (195–205 °F) is optimal for most hot-brew methods. Cold brew is a different chemistry entirely, it extracts different flavor compounds over 12–24 hours.
Water hardness (mineral content): Very soft water (< 50 ppm TDS) under-extracts; very hard water (> 200 ppm TDS) can cause bitter over-extraction. The SCA recommends 75–250 ppm total hardness.
Coffee freshness: Ratio can't compensate for stale beans — CO₂ has off-gassed and volatile aromatics are lost. Use beans within 2–4 weeks of roast date for best results.
Pour technique and brew time: The ratio sets the volume framework; dialing in the taste still requires adjusting grind, temperature, and pour technique to hit the target extraction yield (18–22% for filter coffee).

Frequently Asked Questions

How do I adjust if my coffee tastes too weak?

Increase the coffee dose (lower ratio number — e.g., from 1:15 to 1:13). Before adjusting ratio, check your grind size: too coarse = weak and watery. If the flavour is flat or thin, grind finer first. If it's under-extracted (sour, hollow), also grind finer or brew hotter.

Should I measure coffee by weight or volume?

Always by weight (grams). Coffee bean density varies by roast level — a light roast has denser, heavier beans than a dark roast. A tablespoon of light roast can weigh 10–12% more than a tablespoon of dark roast. A kitchen scale gives consistent results regardless of roast.

What water temperature should I use?

For filter methods (V60, AeroPress, French Press): 90–96 °C (194–205 °F). Lighter roasts benefit from the higher end of that range; darker roasts can go slightly lower. Never use boiling water (100 °C), it over-extracts bitter compounds. Let your kettle cool 30–60 seconds after boiling.

What is the SCA golden ratio?

The Specialty Coffee Association (SCA) golden ratio recommends 55–60g of coffee per liter of water (1:16 to 1:18 ratio) for drip/filter methods. This ratio was established through research on taste preference and extraction yield. Methods like espresso and AeroPress use much higher ratios for concentrated results.

Why does espresso use so much less water than filter coffee?

Espresso uses a 1:2 coffee-to-water ratio (e.g., 18g coffee → 36g espresso), compared to 1:15 for filter. This is because espresso extraction uses pressure (9 bar), which dissolves more soluble compounds in less water. The result is a concentrated shot meant to be consumed in small volume or used as a base for milk-based drinks.

What is the ideal coffee-to-water ratio?

The Specialty Coffee Association (SCA) 'Golden Cup' standard is 55 g of coffee per litre of water (about 1:18), which produces a balanced brew with 1.15–1.35% TDS (total dissolved solids). In practice, most specialty coffee drinkers use 1:15 to 1:17 for pour-over and 1:12 to 1:15 for French press. Taste is subjective — use these as starting points and adjust to your preference.

Should I measure coffee by weight or volume (tablespoons)?

Always by weight when possible. Coffee density varies significantly by roast level and grind size — light-roast beans are denser than dark-roast beans. A tablespoon of light-roast whole beans weighs noticeably more than a tablespoon of dark-roast coarsely ground coffee. Weight in grams is the only consistent measurement across roasts and grind sizes.