Name: Cold Brew Concentrate Recipe: Simple 1:4 Ratio
Prep time: 15 min
Cook time: 12 h
Total time: 12 h 15 min
Ingredients: 240 g (8.5 oz) Coffee, ground coarse, whole bean ground at home, or a bag sold in a cold brew coarse grind; 960 g (33.9 oz) Cold or room-temperature water, about 960 mL

15 minutes of work, then 12 hours on the counter

Weigh 240 g of coffee. If you grind your own, grind it coarse, like coarse sea salt.

Put the coffee in a lidded jar or pitcher that holds at least 1.5 L. Pour in 960 g of water and stir until every ground is wet.

Cover and leave at room temperature for 12 hours.

Strain through a fine mesh strainer, then again through a paper filter or clean cloth. Let it drain on its own; don't press the grounds.

Pour the concentrate into a clean jar, seal it and refrigerate. Expect about 480 mL.

To serve, pour 1 part concentrate and 2 parts cold water or milk over ice. OXO suggests 1:2 or 1:3; Toddy, 1:2.

Every drink on the site starts here. One batch gives about 480 mL of concentrate, which is four 360 mL glasses at a 1:2 dilution. It keeps in the fridge, so one batch can carry you through the week.

Where the numbers come from

Ratio, 1:4 by weight. The calculator’s default concentrate ratio. OXO’s insert says 10 oz of coffee to 40 oz of water, which is 1:4; its gram figures come to 1:4.2. Filtron’s instructions work out to 1:4.2 and Toddy’s to 1:5.6, so 1:4 sits at the strong end of what the makers publish.
Steep, 12 hours. Inside the 8–24 hours the makers’ instructions give (OXO and Filtron 12–24, Toddy 8–24). In one study, caffeine levelled off at 6–7 hours at room temperature. The steep time Lab file covers what that does and doesn’t tell you about flavor.
Yield, about 480 mL. The grounds keep roughly 2 g of water per gram of coffee, so 960 g of water gives 960 − 2 × 240 = 480 mL. Treat that retention figure as an estimate. Makers’ published yields run from 1.3 to 2.1 g/g, so yours may differ.

Storing it

Keep it sealed in the fridge and use it within about a week. The storage Lab file has the sources. To brew a different amount, the calculator link below rescales the weights.

What to make with it