What is the best cold brew ratio?

The most common cold brew ratios are 1:5 (coffee to water by weight) for a concentrate, and 1:8 for ready-to-drink cold brew. A 1:5 concentrate is diluted 1:1 with water or milk when served, giving an effective ratio of 1:10. Specialty coffee guides often suggest 1:4 to 1:5 for concentrate and 1:7 to 1:8 for ready-to-drink. Ratios are measured by weight (grams) because volume measurements vary depending on how finely the coffee is ground.

How long should cold brew steep?

Cold brew steeped in the refrigerator (around 4 degrees Celsius) typically takes 18 to 24 hours. Room temperature steeping (around 20 degrees Celsius) is faster, usually 12 to 14 hours, but carries a slightly higher risk of bacterial growth if left too long. Most home brewers find 20 hours in the fridge produces a smooth, low-acidity result. Once brewed, cold brew concentrate keeps in the refrigerator for up to two weeks.

Should I measure cold brew coffee by weight or volume?

Weight (grams) is the most accurate method because the volume of ground coffee varies significantly depending on grind size and how tightly it is packed. A coarse cold brew grind, which is recommended, is much less dense than an espresso grind. Measuring by weight gives consistent results every batch. Water volume (millilitres) is fine to measure by volume since 1 ml of water weighs approximately 1 gram.

Cold Brew Ratio Calculator

This calculator works out how much coffee and water you need for cold brew, using the weight-based ratio method favoured over guessing with tablespoons or cups. Enter how much coffee you have in grams, then choose a brew style from a strong 1:4 concentrate through to a light 1:8 ready-to-drink, a few ratios in between, or a custom ratio, plus how you want the water shown (millilitres, litres, cups or US fluid ounces), your grind size, and expected steep time. The results panel returns your coffee weight, the exact water needed, the ratio in use, and the approximate yield once the grounds are strained out, since coffee absorbs some water as it steeps. Below that sits a table of common batch sizes at your chosen ratio, a full recipe breakdown, and a brewing guide covering grind size, steep time, serving dilution and fridge shelf life, finishing with a plain-English recipe summary. Use it to scale a recipe up or down, work out how much concentrate to dilute when serving, or plan how many 250 ml serves a batch will yield. Ground coffee volume varies with grind size, so measuring by weight gives more consistent results than scooping by cup or spoon. Actual yield after straining depends on your grind and filter method, so treat the figures as a reliable starting recipe rather than an exact science.

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Standard Method Weight-based ratio: water (g) = coffee (g) x ratio multiplier. 1 ml water = 1 g.

1. Your Coffee

Coffee amount (grams)

Cold brew style

Custom water ratio (parts water per 1 part coffee)

: 1

2. Output Units

Display water volume as

Grind size used

Steep time

Your Cold Brew Recipe

Coffee

Grams (by weight)

Water Needed
-
ml

Ratio

Coffee : Water

Yield (After Straining)

ml yield

Common Batch Sizes at Your Ratio

Coffee	Water (ml)	Water (cups)	Total yield	Serves (250 ml)

Recipe Breakdown

Coffee-

Water-

Water (volume)-

Ratio used-

Total brew volume-

Approx. yield after straining-

Brewing Guide

Grind size-

Steep time-

Water temperatureCold or room temp (never hot)

Dilution on serving-

Fridge shelf lifeUp to 2 weeks (concentrate)

Serves at 250 ml-

Recipe summary: Enter your coffee amount above.

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

Ratio	Style	Strength	How to Serve
1:4	Strong concentrate	Very strong	Dilute 1 part brew with 3 parts water or milk
1:5	Standard concentrate	Strong	Dilute 1:1 with water or milk
1:6	Medium	Medium	Serve over ice or dilute slightly
1:7	Ready-to-drink light	Mild	Serve as-is over ice
1:8	Ready-to-drink	Light	Serve as-is, good for beginners

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.

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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.