Cold Brew Coffee Ratio Calculator (Concentrate & Ready-to-Drink)
Scale cold brew to any jar or batch. Pick concentrate or ready-to-drink and get exact amounts.
What this tool does
Cold brew is less a brew "method" and more a long steep — coarse grounds and cold or room-temperature water sit together for 12–24 hours, slowly extracting flavor without heat. Because there is no heat to force extraction, you need a lot more coffee than a hot brew. The standard concentrate ratio is 1:8 (one part coffee to eight parts water by weight) — roughly twice as strong as you would ever drink it, intended to be diluted with water, milk, or ice. A ready-to-drink batch runs about 1:15, similar to a strong drip brew.
Steep coarse grounds in the fridge for 12–18 hours, then strain through a fine mesh and paper filter. Dilute 1:1 before drinking. Concentrate keeps for up to two weeks refrigerated.
How to use this tool
Choose concentrate or ready-to-drink
Concentrate is ideal if you want flexibility — dilute 1:1 with water or milk to taste, or use it in coffee cocktails and ice drinks. Ready-to-drink skips the dilution step but uses more coffee per serving.
Enter your water volume
Type the amount of water you're working with, or tap a preset. Most mason jars hold 500 ml to 1 liter; a large pitcher is usually 1.5–2 liters.
Grind coarse and steep
Cold brew needs an extra-coarse grind — similar to raw sugar or coarsely cracked peppercorns. Fine or medium grinds over-extract over a 12-hour steep and turn bitter. Add coffee and water to a jar, stir, cover, and refrigerate.
Strain and store
After 12–18 hours, strain through a fine-mesh sieve lined with a paper coffee filter. Store concentrate in the fridge for up to two weeks; ready-to-drink for about a week.
Pro tips
- Room-temperature steeping (often called "room temp cold brew") cuts the time to 8–12 hours and produces a slightly brighter flavor. Refrigerator steeping is gentler and more forgiving if you overshoot the steep time.
- Use a medium-dark or dark roast for cold brew. The lack of heat means light roasts can come out grassy and underdeveloped.
- Double-filtering (mesh sieve then paper filter) produces a crystal-clear concentrate with no sediment — worth the extra step if you're serving guests.
- Cold brew concentrate freezes well in ice cube trays. Drop a cube into a glass and pour milk over it for a quick iced latte.
Why it matters
Cold brew has a notably lower acidity than hot-brewed coffee — typically 60–70% less, according to research from Toddy. That makes it a good option for people who find regular coffee hard on their stomach. The slow, cold extraction also produces a naturally sweet, mellow flavor that doesn't need much sugar.
Frequently asked questions
What is the best cold brew ratio?
Use about 1:8 coffee to water for a concentrate you dilute later, or 1:15 for a ready-to-drink batch. This calculator handles both.
How long should cold brew steep?
Steep coarse grounds in the fridge for 12–18 hours. Longer extracts more strength but can turn bitter past about 24 hours.