Tool
Cold-brew batch and dilution calculator
Coffee and water for a batch, how much cold brew that will actually yield, how far to dilute it and how many servings it makes — for whichever brew ratio and dilution you choose, since neither has a correct value.
Water to brew with
800 g
A concentrate. Brews this strong are normally diluted with water or milk before drinking, often by about as much again or more. Expect roughly 550–650 ml of cold brew once strained — an estimate, because the grounds keep some of the water.
- Cold brew after straining
- about 550–650 ml (estimate)
- Finished drink
- about 1100–1300 ml once diluted 1:1
- Servings
- about 4.4–5.2 of 250 ml
How this was worked out
Brew water = coffee × brew ratio
100 g × 8 = 800 g
Cold brew ≈ water − what the grounds keep
grounds keep about 1.5× to 2.5× their weight = 550–650 ml
This is the one estimate here. It varies with grind and how long the grounds drain; weigh your own batch once and you will know your own figure.
Finished drink = cold brew × (1 + dilution)
× 2 = 1100–1300 ml
There is no single correct cold-brew ratio or dilution. This computes the recipe you chose; taste it, and change one of the two numbers next time.
An evidence-based range, not a measurement
What to do with the result
- You have the amounts and want the method: steeping, filtering, keeping: Cold brew: concentrate or ready-to-drink
- The glass is too weak or too strong: Cold brew too weak or too strong
- It tastes wrong in some other way: Make my coffee better: cold brew
- You want a caffeine range for a glass: Caffeine estimator
How it works
There are three ways in. Planning a batch multiplies your coffee by the brew ratio to give the water, then estimates how much liquid you will strain off, because the grounds keep some of the water. Diluting takes the cold brew you have and a dilution: 1:2 means one part cold brew to two parts water or milk. Working back from servings divides the finished drink you need by one plus the dilution to give the cold brew required, and, if you give a brew ratio, the coffee and water to make it. Everything is exact arithmetic except the yield of a batch, which is shown as a range.
What the inputs mean
- Brew ratio
- Grams of water for each gram of coffee when the batch is made. About 1:4 to 1:8 gives a concentrate meant to be diluted; about 1:12 to 1:16 gives something drunk as it is. Recipes vary and none is canonical.
- Estimated yield
- The liquid left after straining. Spent grounds hold back roughly one and a half to two and a half times their own weight in water, so the yield is given as a range between those.
- Dilution
- Parts of water or milk per part of concentrate. This is a serving decision made after brewing, and is a different thing from the ratio the concentrate was brewed at.
Worked examples
A black cold brew from concentrate
- Cold brew 100 ml
- Dilution 1:2
Result: 200 ml of water, for a 300 ml drink.
Planning a concentrate
- Coffee 100 g
- Brew ratio 1:8
- Dilution 1:1
- Serving 250 ml
Result: 800 g of water. Expect roughly 550 to 650 ml of concentrate after straining, which is about 1.1 to 1.3 litres of finished drink, or four to five glasses.
The yield is the estimate; the rest follows from it by arithmetic.
Working back from six glasses
- 6 servings
- Serving 200 ml
- Dilution 1:1
- Brew ratio 1:8
Result: 1,200 ml of finished drink needs 600 ml of cold brew and 600 ml of water or milk. Brewing that at 1:8 takes roughly 92 to 109 g of coffee.
Common mistakes
Confusing dilution ratio with brew ratio
The brew ratio decides how strong the concentrate is; the dilution decides how much you water it down afterwards. Two concentrates brewed differently need different dilutions to land in the same place.
Diluting to taste over ice and then repeating the recipe without it
Melting ice adds a substantial amount of water. The same numbers without ice will taste much stronger.
What the result does not mean
- Dilution says nothing about how the concentrate was extracted. A weak concentrate diluted less is not the same drink as a strong one diluted more.
What this does not account for
- There is no single correct brew ratio or dilution — this only computes the arithmetic for whichever you choose.
- Ice is not counted. It dilutes as it melts, so a drink built over ice ends up weaker than the numbers here.
- The yield estimate assumes the grounds keep between 1.5 and 2.5 times their weight in water. Fine grinds and short draining keep more; coarse grinds and pressing keep less. Weighing one batch gives you your own figure.
- Treats one gram of cold brew as one millilitre, as home recipes do.