Cold Brew Ratio Calculator

Concentrate thinking

Cold brew extracts slowly in cold water, producing a concentrate that stores well and dilutes per cup. The 1:4–1:5 concentrate band gives flexibility (water, milk, cocktails), while 1:8 ready-to-drink trades flexibility for fridge space. The universal error is skipping the dilution step — the math above prices it into every batch.

Time, temperature, grind

16–20 hours refrigerated is the consensus window: shorter tastes thin, past 24 hours picks up woody bitterness. Coarse grind is non-negotiable — fine grind over-extracts and clouds. And the fridge steep beats counter steep for sweetness; room temperature runs faster and wilder.

The absorption constant

Grounds absorb roughly their weight in water: a 200 g coffee batch holds back ~170 ml of liquid. The calculator subtracts it — the difference between planning yield and discovering a smaller harvest than the math promised. Scaling for guests means scaling concentrate AND dilution water.