Cold Brew Ratio Calculator
Concentrate you cut at the glass, or a batch at drinking strength. Coffee in, water and steep time out, and the dilution that gets a jar of concentrate to a good glass.
The strength of the finished glass.
500g
16.9 fl oz
100 g of coffee in 500 g of water makes about 300 ml of concentrate after the grounds keep their share. Cut it one part to 1.8 parts water for a 1:14 glass: about 4 servings of 8 oz.
How to Use This Calculator
- Choose how you brew. Concentrate is brewed strong and diluted per glass; ready to drink is brewed at the strength you pour.
- Enter your coffee in grams, ground extra coarse. The water follows the ratio.
- Set the ratio. 1:5 is a typical concentrate; 1:13 is a typical ready-to-drink batch. The scale shows the usual range for each.
- Pick where it steeps. The fridge is slower and cleaner; the counter is faster and a little rounder.
- For concentrate, pick the glass strength. The tool tells you how many parts of water to add to one part of concentrate.
Concentrate or Ready to Drink
A concentrate takes less jar space and keeps for a week or more in the fridge, and because you dilute at the glass you can pour it long with water, short over ice, or with milk, all from the same batch. It costs more coffee per finished glass, because a strong brew extracts a little less efficiently than a dilute one.
Ready to drink uses the coffee more efficiently and is simpler to serve, but it takes a bigger vessel and it is committed to one strength. If you drink it black and always the same way, brew ready to drink; if a household drinks it three ways, brew concentrate.
What the Grounds Keep
Coarse grounds hold on to about two grams of water for every gram of coffee, so a litre of water over 100 g of coffee gives you roughly 800 ml back. The calculator's yield and serving counts include that loss; the water figure is what you pour in. Pressing the grounds to get the last of it back pushes fines and bitterness through with the liquid, so let it drain and accept the difference.
Dilution
The dilution is the arithmetic between the brew ratio and the ratio you want in the glass. A 1:5 concentrate cut one part to two parts water lands at 1:15; cut one to one, it is 1:10 and much stronger. Milk counts as a part. Ice counts as a part too, once it melts, so a glass that starts right ends up light: pour it a little strong over ice.
Steeping
Twelve to sixteen hours at room temperature, or sixteen to twenty-four in the fridge, is the range worth working in. Longer than that adds more woody bitterness than sweetness. Use a genuinely coarse grind, like breadcrumbs; fine grounds turn the batch muddy, slow the strain, and taste harsh. Our cold brew at home guide covers beans, vessels and filtering, and the grind size chart shows how coarse is coarse.