Cold Brew Calculator
Calculate coffee and water amounts for cold brew concentrate or ready to drink.
This tool is for informational and educational purposes only. It is not a substitute for professional financial, medical, legal, or engineering advice. See Terms of Service.
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Cold brew coffee is made by steeping coarsely ground coffee in cold water for 12-24 hours. The ratio of coffee to water determines whether you get a concentrate or a ready-to-drink brew. This calculator gives you exact amounts:
- Enter your desired volume. Type how many cups of cold brew you want to make. This is the total liquid volume before steeping, which will reduce slightly during straining. 4 cups is a good starting batch for most mason jars or pitchers.
- Choose your strength. Concentrate (1:5 ratio) gives you a strong brew you dilute 1:1 with water or milk before drinking. Ready-to-drink (1:8 ratio) can be poured straight over ice. Concentrate is more efficient if you store it in the fridge, since it takes up less space.
- Follow the steep instructions. Combine coffee and cold water, stir to saturate all grounds, cover, and refrigerate. The recommended steep time appears in the results. Do not steep at room temperature for more than a few hours.
Use a coarse grind (similar to French press grind) for cold brew. Fine grinds make filtering difficult and can result in a bitter or overly cloudy brew.
About Cold Brew Ratios
Cold brew is made with time instead of heat. Because no heat is involved, the extraction process takes 12-24 hours. Cold water extracts different compounds than hot water, resulting in a smoother, less acidic cup with lower bitterness. The standard concentrate ratio of 1:5 (1 part coffee to 5 parts water by weight) produces a brew that is roughly twice the strength of regular coffee. Ready-to-drink at 1:8 produces a strength similar to strong drip coffee.
Coffee weight and volume are not the same. This calculator uses weight (grams) as the primary measurement for accuracy, since coffee grounds can vary significantly in density. One tablespoon of coarsely ground coffee weighs approximately 5 grams, which is used here as the tablespoon estimate. For best results, use a kitchen scale.
Frequently Asked Questions
What is the best ratio for cold brew coffee?
The most common ratios are 1:5 for concentrate and 1:8 for ready-to-drink. A 1:5 ratio means 1 gram of coffee per 5ml of water (or 1 oz per 5 oz). This produces a rich concentrate that is typically diluted before drinking. A 1:8 ratio produces a cold brew that can be poured directly over ice. The "best" ratio is personal preference. Start with 1:8 if you prefer a milder coffee, or 1:5 if you like flexibility in adjusting strength at serving time.
How long should cold brew steep?
For concentrate, 16-20 hours in the refrigerator is ideal. For ready-to-drink, 12-14 hours is usually enough. Steeping longer than 24 hours can result in over-extraction, producing a bitter or flat-tasting brew. Always steep in the refrigerator to prevent bacterial growth. Room temperature cold brew should not steep for more than 12 hours before being moved to the fridge.
What grind size should I use for cold brew?
Use a coarse grind, similar to what you would use for a French press. Coarse grounds are easier to filter, less likely to produce a muddy or bitter brew, and extract well over the long steep time. Fine grinds will clog filters and over-extract, resulting in bitterness. If you are using a standard drip grind from a pre-ground bag, it will work but may need a shorter steep time (12 hours) and careful filtering through a paper filter or fine mesh.
How long does cold brew last in the fridge?
Strained cold brew concentrate keeps in the refrigerator for up to 2 weeks. Ready-to-drink cold brew is best within 7-10 days. The flavor peaks in the first few days and can gradually become flat or slightly sour over time. Store in an airtight container (mason jar, sealed pitcher) to prevent flavor absorption from other foods in the fridge. Do not store cold brew with the grounds still in it — strain before refrigerating.