Cold Brew Ratio Calculator

The ratio is read from what you put in the jar, not from the strength button: the button only sets the target, and when your coffee and water are more than 5% away from it the page says how much coffee the target would take. Light is 1:10, Medium 1:8 (Counter Culture's concentrate, which it dilutes between 2:1 and 1:1) and Strong 1:5, close to Stumptown's 12 oz of coffee to 64 oz of water, cut 1:1 with water or milk. Steep time and where it steeps sit under Advanced Options, and the steep window uses 14 hours at room temperature until you change them.

Type the water in ml, litres, cups (237 ml) or US fl oz (29.5735 ml); everything after that works in ml. 4 cups is 948 ml and takes 118.5 g of coffee at Medium.

With the starting values, 50 g of coffee and 400 mL of water give 1:8 and a yield of 315 mL, about 1.3 cups. For 1,000 mL at Medium use 125 g of coffee, which yields 788 mL, about 3.3 cups; at Strong use 200 g, which yields 660 mL, about 2.8 cups. A 14-hour steep at room temperature gets a 14–18 hour window; in the fridge it reads 14+ hours.

ratio = water (mL) ÷ coffee (g), yield (mL) = water − 1.7 × coffee, cups = yield ÷ 237

The 1.7 mL per gram is water that stays in the wet grounds; a cold-brew patent (US 11,284,740) puts it at about 1.5 to 2 litres per kilogram and uses 1.7 to estimate yield. If the grounds would keep all the water, the page asks for more water or less coffee instead of showing a yield. A room-temperature window starts at the larger of 12 hours and your steep time and runs up to 4 hours longer, stopping at 20 hours. Where no range is left (a steep of 8 hours or less, or of 20 or more) it shows one figure, and past 20 hours it adds that the steep is already beyond the limit. A refrigerator steep shows your time with a plus sign, because cold extraction is slower. Steeps under 8 hours get a note about weak flavour, and steeps over 20 hours one about over-extraction. The grind is always extra coarse.

Very mild (weaker than 1:10) and very strong (stronger than 1:4, beyond the Strong setting's 1:5) brews get a caution. The dilution advice follows the strength button you press: Strong says to cut 1:1, Medium says 1:1 or 2 parts concentrate to 1 part water, and Light says to taste it first.