Cold Brew Coffee Ratio Calculator

Formula used

Cold brew is an immersion method with a coffee-to-water ratio for the steep:

Water (g) = Coffee (g) × N

There are two common targets. A concentrate uses a strong ratio (about 1:5 to 1:8) that you later dilute with water, milk or ice. A ready-to-drink batch uses a weaker ratio (about 1:15 to 1:17) you sip as-is. After a long steep, the coarse grounds retain a little over twice their weight in water, so the liquid you strain off is less than the water you added.

If you set a dilution of D, the final drink volume ≈ concentrate × (1 + D).

Worked examples

Concentrate. 150 g of coffee at 1:8 steeps in 1200 g of water, yielding roughly 880 ml of concentrate. Diluted 1:1.5 that makes about 2.2 litres of drink.

Ready-to-drink jar. Fill a 1-litre jar (1000 ml water) at 1:16 → about 63 g of coffee, sipped without dilution (set dilution to 0).

Small batch concentrate. 80 g at 1:7 uses 560 g of water for a fridge-friendly bottle.

How to use this calculator

1. Decide whether you are making concentrate (dilute later) or ready-to-drink.
2. Choose to start from coffee or water and enter the amount in grams.
3. Set the steep ratio: low (1:5–1:8) for concentrate, high (1:15–1:17) for ready-to-drink.
4. Set a dilution if making concentrate, or 0 if not.
5. Press Calculate, steep 12–18 hours in the fridge, then filter.

Cold brew ratio guide

Choosing a steep ratio and typical dilution.

Use a coarse grind to keep the brew clean and easy to filter.

Who should use this calculator

Anyone making cold brew at home in a jar, bottle, or dedicated cold brew maker. It is just as useful for a single bottle as for a big-batch concentrate you keep in the fridge all week, and it removes the guesswork from how much to dilute.

What each input means

• Start from — coffee dose or water amount.
• Amount — grams of coarse coffee or millilitres of water.
• Steep ratio — water per gram of coffee during the steep. Lower = stronger concentrate.
• Dilution — how many parts water (or milk) you add per part of finished concentrate.

How to read your result

You get the coffee and water to combine, the steep ratio, an estimate of the concentrate you will strain off, and, if you set a dilution, the final drink volume. The concentrate is less than the water you added because the saturated grounds hold onto some liquid.

Common mistakes to avoid

• Using a fine grind. Fines make filtering slow and the brew silty. Grind coarse, like for French press.
• Steeping too long at room temperature. Steep in the fridge; over-long warm steeps can taste woody or sour.
• Forgetting to dilute concentrate. A 1:8 concentrate is strong — dilute before drinking.
• Storing too long. Concentrate keeps about 1–2 weeks refrigerated; flavour fades after that.

Limitations of this calculator

This estimates weights and volumes. Actual concentrate strength depends on grind size, steep time and temperature, and bean roast. The retention figure (~2.1 ml per gram) is an average for a long cold steep. Use the output as a reliable starting recipe and adjust dilution to taste.