Brew lab · free tools
Brew math, without the guesswork.
Scale a recipe to your dose, understand the ratio behind it, and keep the numbers consistent from the first cup to the hundredth.
Ratio calculator
Start with the numbers.
15 g coffee × 16 = 240 g water
Dial-in tip: keep the ratio fixed, then adjust grind until the cup tastes balanced.
Three formulas
The only math you need.
A ratio controls strength. Dilution controls the final cup. Grind and temperature control extraction. Keep these separate in your head and dialling in becomes much simpler.
Water weight
water = coffee × ratio
For a 1:16 ratio and 18 g of coffee: 18 × 16 = 288 g of water.
Dilution
final = concentrate + water
A 1:8 cold brew concentrate diluted 1:1 becomes roughly a 1:16 ready-to-drink cup.
Temperature
light = hotter · dark = cooler
Start at 94 °C for light roasts and 90–92 °C for dark roasts. Change in 1–2 °C steps.
Reference chart
Ratios for every brewer.
| Method | Ratio | Coffee | Water | Grind | Temperature |
|---|---|---|---|---|---|
| V60 / Pour over | 1:16 | 15 g | 240 g | Medium-fine | 92–96 °C |
| AeroPress | 1:13.5 | 17 g | 230 g | Medium-fine | 88–92 °C |
| French press | 1:15 | 30 g | 450 g | Coarse | 92–96 °C |
| Espresso | 1:2 | 18 g | 36 g | Fine | 90–94 °C |
| Cold brew | 1:8 | 125 g | 1,000 g | Extra coarse | Cold / room temp |
Ratios are starting points, not rules. Adjust grind and yield to suit the coffee, roast level, and your taste.
From numbers to flavour
Pick a method. Follow the recipe.