Cold Brew Ratio Calculator

How the Cold Brew Ratio Formula Works

Cold brew ratio is always expressed as coffee : water by weight. The formula is straightforward:

Water (g) = Coffee (g) x Ratio multiplier

For example, at a 1:5 ratio with 100 g of coffee: Water = 100 x 5 = 500 g = 500 ml. Because water has a density of approximately 1 g/ml, grams and millilitres are interchangeable for water. The total brew volume is coffee weight plus water volume, though the actual liquid yield after straining out the coffee grounds is typically about 50 to 75 percent of the water added across these ratios because the grounds absorb roughly 2 g of water per gram of coffee (for example about 60 percent of the water at a 1:5 ratio).

Choosing Your Ratio

The 1:5 concentrate ratio is the most popular for home cold brew because it gives flexibility: you can dilute to taste, add milk, or use it in recipes. If you prefer not to dilute, a 1:7 or 1:8 ratio produces a pleasant ready-to-drink cold brew.

Why Weight Over Volume for Coffee

Measuring coffee by volume (tablespoons or cups) gives inconsistent results because the density of ground coffee varies with grind size. Cold brew requires a coarse grind, which is much less dense than an espresso grind. The same volume of coarse-ground coffee can weigh significantly less than medium-ground coffee. Measuring by weight (grams using a kitchen scale) gives the same result every time, regardless of grind size or how loosely the grounds are packed.

Steep Time and Temperature

Cold brew is steeped in cold or room-temperature water, never hot. The low temperature extracts coffee slowly, producing a smooth, low-acidity drink. Steeping in the refrigerator (4 degrees Celsius) takes 18 to 24 hours and is the safest method. Steeping at room temperature (around 20 degrees Celsius) takes 12 to 14 hours and produces a slightly different flavour. Steeping too long, regardless of temperature, can produce bitter or grassy notes.

Related Calculators

• Maths and Stats Calculators: browse all ratio, proportion, and formula tools.
• Coffee Habit Cost Calculator: find out how much your coffee habit costs per year.
• Ratio Calculator: scale any ratio up or down.
• Baker's Percentage Calculator: the same weight-based ratio method used in baking.

Sources and method: Weight-based ratio formula (water g = coffee g x ratio). Specialty Coffee Association brewing guidelines. Standard cold brew temperature and steep time ranges from published coffee science literature.

This calculator provides indicative quantities based on standard cold brew ratios. Actual yield after straining will vary depending on grind size and filter method. Coffee grounds typically absorb approximately 2 g of water per gram of coffee. Adjust ratios to your personal taste preference.