What is a coffee brew ratio?
A coffee brew ratio is the relationship between the weight of coffee grounds and the weight of water. It's written as 1:X, meaning 1 part coffee to X parts water. For example, 1:15 means 1 gram of coffee for every 15 grams (or milliliters) of water.
Professional baristas use weight-based ratios because coffee density varies with grind size and roast level — volume measures like scoops are unreliable. A digital scale and a consistent ratio are the two most important tools for repeatable, delicious coffee.
Why coffee-to-water ratio matters
- • Controls strength. A lower ratio (1:12) uses more coffee per unit of water and produces a stronger, more concentrated cup. A higher ratio (1:17) uses less coffee and produces a lighter, more delicate cup.
- • Determines consistency. Without a fixed ratio, your coffee tastes different every day. A consistent ratio removes guesswork.
- • Affects extraction balance. Ratio works together with grind size and water temperature. A slightly higher ratio can compensate for a finer grind, and vice versa.
- • Saves coffee. Brewing too strong and then diluting wastes coffee. Dialing in the right ratio means you use exactly what you need.
How 1:15 differs from 1:17
The difference between 1:15 and 1:17 is about 13% more coffee at 1:15. That might not sound like much, but in the cup it's noticeable.
| Ratio | Coffee for 300g water | Character |
|---|---|---|
| 1:12 | 25.0 g | Very strong, syrupy, intense |
| 1:14 | 21.4 g | Strong, full-bodied |
| 1:15 | 20.0 g | Balanced, rich |
| 1:16 | 18.8 g | Medium, clean |
| 1:17 | 17.6 g | Lighter, tea-like, delicate |
How to calculate water from coffee (and coffee from water)
Coffee → Water
Multiply coffee by the ratio.
Example: 20 g × 15 = 300 g water
Water → Coffee
Divide water by the ratio.
Example: 300 g ÷ 15 = 20 g coffee
Worked examples
How much coffee for 300 ml water at 1:15?
Coffee = 300 ÷ 15 = 20 g. Water = 300 g. Brew volume ≈ 300 ml.
How much water for 18 g coffee at 1:16?
Water = 18 × 16 = 288 g. Coffee per serving = 18 g. Ratio confirmed 1:16.
French press for 4 servings at 1:14
Coffee = 4 × 22 g = 88 g. Water = 88 × 14 = 1,232 g. Per serving: 22 g coffee, 308 g water.
Cold brew concentrate at 1:5
For 500 g water: coffee = 500 ÷ 5 = 100 g. Dilute 1:1 or 1:2 with water or milk before serving.
Coffee ratio vs strength
Ratio is the recipe: how much coffee and water you start with. Strength is the result: how much dissolved coffee ends up in your cup, measured as TDS (total dissolved solids).
Two brews can have the same ratio but different strength if grind size, water temperature, or brew time differ. That's why changing your ratio is only one lever — always adjust grind first, then ratio.
- → Too weak? Grind finer or lower the ratio (use more coffee).
- → Too strong or bitter? Grind coarser or raise the ratio (use less coffee).
- → Sour or under-extracted? Grind finer before changing ratio.
How grind size affects extraction
Grind size controls how fast water extracts flavor from coffee. Finer grinds expose more surface area and extract faster; coarser grinds extract slower.
| Grind | Typical method | Extraction |
|---|---|---|
| Fine | AeroPress, espresso | Fast, intense |
| Medium-fine | Pour over, drip | Balanced, clear |
| Medium-coarse | French press | Slow, full-bodied |
| Coarse | Cold brew | Very slow, smooth |
Why a scale is useful for coffee brewing
A digital scale is the single most important upgrade for consistent coffee. Here's why:
- • Weight is accurate — scoops vary by 20% or more depending on grind and bean density.
- • You can measure water as you pour, not just guess at the kettle.
- • Ratios become repeatable, so you can tweak one variable at a time.
- • You can track yield: 20 g coffee in, 300 g water, 280 g brewed coffee out — a 93% yield.
How ratios vary between brewing methods
There is no universal "best" ratio. Each brew method has a typical range, but your grind, roast, and taste preference matter more than any single number.
| Method | Typical ratio | Notes |
|---|---|---|
| Pour Over | 1:15 – 1:17 | Medium grind, slow pour, clean cup |
| French Press | 1:12 – 1:15 | Coarse grind, full immersion, full body |
| AeroPress | 1:12 – 1:14 | Fine-medium, short brew, concentrated |
| Drip Coffee | 1:15 – 1:17 | Medium grind, machine-dependent |
| Cold Brew | 1:4 – 1:8 | Coarse grind, 12–24 hour steep, concentrate |
These are starting points, not rules. Adjust based on taste, roast level, and grind.