Interactive tool · 計算
Cold Brew Ratio Calculator
Tell it how much cold brew you want and how strong. It tells you exactly how much coffee and water to use — by weight, the only way that's repeatable.
How the math works
Cold brew ratios are expressed by weight — 1:5 means 1 gram of coffee for every 5 grams (= 5 ml) of water. Volume scoops lie: a "cup of grounds" can vary by 30 grams depending on grind and roast. A $15 kitchen scale ends the guessing forever.
The calculator also corrects for the cold brew tax nobody mentions: grounds absorb roughly twice their weight in water. Brew with exactly the water your target volume needs and you'll come up short, so I add the absorbed water back into the water figure for you.
Which ratio should you pick?
- 1:4 to 1:5 — concentrate. The flexible choice. Cut it 1:1 with water or milk over ice, and one batch serves black-coffee drinkers and latte people alike. 1:5 is the ratio I brew every control batch with.
- 1:8 — ready to drink. Straight from the fridge to the glass, no dilution. Closest to what a café hands you.
- 1:10 and up — light. Tea-like body. Some single origins shine here; most grocery beans get watery.
Want the full reasoning, steep-time tests, and grind advice? Start with the brewing guides.