Cold Brew Coffee Ratio Calculator
Cold brew coffee is brewed at room temperature or in the refrigerator over 12-24 hours, producing a smoother, less acidic cup than hot-brewed coffee. The key variable is the coffee-to-water ratio, measured by weight for accuracy and consistency. This calculator lets you choose a batch size and ratio style (concentrate or ready-to-drink) and instantly returns exactly how many grams of coffee grounds and water you need. A 1:4 ratio by weight produces a strong concentrate meant to be diluted before drinking. A 1:8 ratio produces a ready-to-drink strength. Brewing by weight (not scoops) is the single biggest step toward repeatable, professional-quality cold brew at home.
Cold brew ratio formula
Coffee (g) = water (g) / ratio
Example at 1:8 with 1,000 g water: coffee = 1,000 / 8 = 125 g
Approx. yield (mL) = water (g) * 0.85 (accounts for grounds absorption)
Cold brew tips
- Use coarse-ground coffee (like French press grind) to prevent over-extraction and clogged filters.
- Brew in the refrigerator at 38-40 F for 18-24 hours for the safest result (USDA food safety guidance).
- Strain through a paper filter after the primary cheesecloth or metal mesh strain to remove fine sediment.
- Concentrate stored in a sealed container in the refrigerator keeps for up to 2 weeks. Ready-to-drink cold brew keeps for about 1 week.
- Label your container with the brew date to track freshness.
Cold brew: frequently asked questions
What is the standard cold brew ratio?
A common cold brew concentrate ratio is 1:4 coffee to water by weight (1 gram coffee per 4 grams water). For ready-to-drink cold brew, a 1:8 ratio is more typical. Concentrates are diluted 1:1 or 1:2 with water or milk before serving.
Should I measure cold brew by weight or volume?
Weight is far more accurate. Coffee density varies significantly by roast and grind size, so measuring by volume (scoops or tablespoons) produces inconsistent results. Using a kitchen scale and brewing by grams gives reproducible results every batch.
How long should cold brew steep?
At refrigerator temperature (38-40 F), steep for 18-24 hours. At room temperature (68-72 F), steep for 12-16 hours. Steeping longer extracts more bitter compounds. The USDA Food Safety and Inspection Service recommends keeping cold brew refrigerated during and after brewing.
What grind size works best for cold brew?
A coarse grind (similar to French press or coarser) is standard for cold brew. A coarser grind reduces over-extraction during the long steep time and makes filtration easier. Fine grounds clog filters and can make the brew bitter and muddy.
How do I dilute cold brew concentrate for serving?
A typical 1:4 concentrate is diluted 1:1 with water or milk for a drink similar in strength to hot brewed coffee. For a milder drink, dilute 1:2. Track the total water in the recipe including dilution water to understand the effective final ratio.
Official sources
- USDA Food Safety and Inspection Service: Safe Food Handling and Preparation.
- FDA: Buy, Store, and Serve Safe Food.
Reviewed by the CalculatorHub team, edited by James Graham, 14 June 2026. See our methodology.