Cold Brew Ratio Calculator

Cold water extracts far less acid, which is why 1:8 concentrate is drinkable at all.

Coffee125 gCold brew concentrate, 1:8 — diluted before drinking

Water1,000 mL33.81 fl oz

Per cup31.25 g in 250 mL

In tablespoons23.58at about 5.3 g per level tablespoon of ground coffee — which varies with roast, hence the scales

At the SCA standard instead54.95 g55 g per litre, weaker than most home brewing

Strength against SCA2.275×

Grind matters more than ratio. Under-extracted coffee tastes sour and thin, over-extracted tastes bitter and hollow, and neither can be fixed by changing the dose — they are grind problems.

The formula

coffee = water / ratio

Ratios, not spoons

Coffee is measured by ratio because beans differ in density by more than a third between a light and a dark roast, so a scoop is not a fixed quantity. The Specialty Coffee Association standard is 55 g per litre, which is 1:18.2 — rather weaker than most people brew at home.

Grind matters more than ratio

Extraction depends on how much surface the water meets and for how long. A French press steeping four minutes needs a coarse grind; espresso pushing through in 25 seconds needs a fine one. Getting the grind wrong cannot be fixed by adjusting the ratio — under-extracted coffee tastes sour and thin, over-extracted tastes bitter and hollow, and both are ground problems rather than dose problems.

Cold brew is a different drink

Brewing cold for twelve to eighteen hours extracts far less of the acids and bitter compounds, which is why it tastes smooth and sweet at a strength that would be undrinkable hot. Concentrate is usually made at 1:8 and diluted to taste; brewed ready-to-drink it sits nearer 1:15.

Recipes are starting points

Ovens run hot or cold by 20 degrees, flour absorbs water differently by season and brand, and the same joint of meat cooks at a different rate depending on its shape rather than its weight. Everything here is a planning figure that gets you close enough to start, and the thermometer, the scales and your own notes from last time are what finish the job.