Comment fonctionne le calcul
The ratio is by weight throughout, treating 1 ml of water as 1 g. Each method carries a fixed ratio: Pour over (V60) 1:16, Chemex 1:17, French press 1:15, AeroPress 1:14, Espresso 1:2, Moka pot 1:10, Drip / batch brewer 1:17 and Cold brew 1:8. The strength slider rescales it as ratio × (1 − strength ÷ 100) across plus or minus 15, so +15 on a V60 tightens 1:16 to roughly 1:13.6.
Start with the "I have…" select. "A target water amount" divides your figure by the ratio to give coffee; "A target coffee amount" multiplies it to give water; "A number of cups" multiplies your count by the Cup size select — 240 ml US mug, 180 ml SCA cup, 60 ml espresso double or 350 ml large mug — then divides. The grind, brew time and water temperature shown alongside come from the method itself, not from your numbers.
These ratios are fixed starting points, not a model of extraction: roast level, grind fineness, water mineralisation and brewer geometry all shift the cup and none are inputs here. Espresso is a special case, because its 1:2 is a dose-to-yield ratio — the figure the tool labels as water is really the liquid espresso in the cup, not what you put into the machine. In cups mode the g/oz selector is ignored.
FAQ
What is the best coffee to water ratio for pour over? +
The Pour over (V60) preset uses 1:16, so 500 g of water takes 31.3 g of coffee. Chemex and drip sit at 1:17 for a lighter cup and French press at 1:15. The strength slider moves any of them by up to 15 percent.
How much coffee do I need for a French press? +
Select French press for its 1:15 ratio, switch the input to a target water amount, and enter your carafe volume in grams. A 1000 g press takes 66.7 g of coarsely ground coffee, steeped for the four minutes the tool recommends.
What does the strength slider actually change? +
It multiplies the method's ratio by one minus the slider value over 100, across plus or minus 15. Positive values tighten the ratio and use more coffee per gram of water; negative values loosen it. Grind and brew-time recommendations do not move.
Why is espresso listed as 1:2? +
Because espresso is measured dose to yield rather than dose to water. A 1:2 ratio means 18 g of ground coffee producing 36 g of liquid in the cup, so the figure labelled water here is that yield, not what you feed the machine.
Can I measure by volume instead of weighing? +
Not accurately. Scoops vary with grind size, roast level and how the grounds settle, and the ratio here is strictly by weight with 1 ml of water treated as 1 g. A two-gram error per cup is the gap between weak and bitter.
