tags: [] - coffee/brewing - coffee/science aliases: - Coffee to water ratio - Brew ratio - Coffee ratio

Water-to-Coffee Ratio¶

Tags: #coffee/brewing #coffee/science Aliases: Coffee to water ratio, Brew ratio, Coffee ratio Related: Brew Ratio | Extraction Yield | Brewing Fundamentals MOC | Batch brew | Espresso MOC Status: ✅ Complete

Overview¶

The water-to-coffee ratio (also expressed as brew ratio or coffee-to-water ratio) is the relationship between the mass of ground coffee and the mass of water used in a brew, expressed as a ratio such as 1:15 (one part coffee to fifteen parts water). It is one of the two primary variables — alongside extraction yield — that determine the strength (concentration) of brewed coffee. The brew ratio is controlled by the brewer before brewing begins and, together with grind size, water temperature, and contact time, defines the extraction parameters of any brewing method. The SCA Golden Cup Standard specifies an approximate 1:18 ratio (55 g/L) as the target for filter coffee.

How Ratio Determines Strength¶

Strength (measured as TDS — total dissolved solids) is the concentration of dissolved coffee compounds in the brewed liquid. The brew ratio sets the upper bound of achievable strength:

A stronger ratio (more coffee per unit of water, e.g. 1:12) produces a higher maximum TDS — the brewed coffee is more concentrated
A weaker ratio (less coffee per unit of water, e.g. 1:20) produces a lower maximum TDS — the brewed coffee is more dilute

Ratio and extraction yield interact: the same ratio at different extraction yields produces different TDS values. The relationship is:

TDS (%) ≈ Extraction Yield (%) ÷ Brew Ratio

Example: 20% extraction yield at 1:15 ratio → TDS ≈ 1.33%

Common Brew Ratios by Method¶

Brewing method	Typical ratio range	Notes
Espresso	1:1.5 to 1:3 (output ratio)	Expressed as dose:yield by mass; highly concentrated
Moka pot	1:7 to 1:10	Produces concentrated stovetop coffee
AeroPress	1:8 to 1:15	Wide range; dilute for Americano-style or brew as concentrate
Pour over (V60, Chemex)	1:15 to 1:17	Specialty standard; taste preference drives adjustment
Batch brew / drip	1:15 to 1:18	SCA Golden Cup: ~1:18 (55 g/L)
French press	1:12 to 1:17	1:15 common starting point
Cold brew concentrate	1:5 to 1:8	Dilute 1:1 to 1:2 before serving
Turkish coffee	1:9 to 1:10	Small volume; very concentrated

SCA Golden Cup Standard¶

The Specialty Coffee Association defines the optimal filter coffee brew ratio as approximately 55 g of coffee per litre of water — approximately 1:18.2. This is derived from research correlating extraction yield (18–22%) and TDS (1.15–1.45%) with positive sensory evaluation by trained panellists. Many specialty cafés and home brewers use stronger ratios (1:15 to 1:16) by preference.

Adjusting Ratio vs. Adjusting Grind¶

Ratio and grind size have related but distinct effects:

Variable	Primary effect
Brew ratio	Changes strength (TDS) at fixed extraction yield
Grind size	Changes extraction rate and yield at fixed ratio

If a coffee tastes strong and bitter: first adjust grind coarser (to reduce extraction yield), then consider reducing dose (stronger ratio → increase water or decrease coffee).

If a coffee tastes weak and thin: first check extraction yield (may be under-extracted — grind finer), then consider increasing dose.

Measuring Ratio¶

By mass (recommended): Use a scale to weigh both ground coffee (g) and water (g or ml, as 1 ml water ≈ 1 g). This is the most accurate approach and the SCA standard. Example: 20 g coffee to 300 g water = 1:15.

By volume: Using tablespoons of coffee per cup of water — common in domestic settings but less accurate due to variable grind density.

For espresso, ratio is typically measured as dose (g) to yield (g): e.g. 18 g in, 36 g out = 1:2 ratio.

Key Facts¶

Brew ratio is the mass ratio of ground coffee to brewing water (e.g. 1:15 = 1 g coffee per 15 g water)
Together with extraction yield, ratio determines TDS (strength) of the brewed coffee: TDS ≈ Extraction Yield ÷ Brew Ratio
SCA Golden Cup target for filter coffee: ~55 g/L (~1:18); specialty baristas commonly use 1:15 to 1:17
Espresso ratios are very low (1:1.5 to 1:3) — producing highly concentrated shots diluted by small volume
Changing ratio adjusts strength; changing grind size adjusts extraction yield — these are independent levers
Always measure ratio by mass for precision; volumetric measurement varies with grind density

References¶

Changelog¶

Date	Change
2026-04-28	Note created

This article is part of All-About-Coffee.com - The comprehensive coffee knowledgebase.