Concentrate or ready to drink
A concentrate packs in more coffee. The National Coffee Association suggests 1:4 to 1:5, or 200 g of coffee to 1 liter of water. Ready-to-drink cold brew runs about 1:11 to 1:13, and you pour it over ice as it is. A concentrate saves fridge space and lets you set the strength glass by glass. Mix a 1:5 batch 1:1 and you land near 1:10.
| 500 ml jar | 1 L jar | 1.9 L jar | |
|---|---|---|---|
| Water | 500 g, 17 oz | 1,000 g, 34 oz | 1,900 g, 64 oz |
| Coffee for concentrate, 1 : 5 | 100 g | 200 g | 380 g |
| Concentrate you pour off, about | 300-350 g | 600-700 g | 1,140-1,330 g |
| Coffee for ready to drink, 1 : 12 | 42 g | 83 g | 158 g |
Grind and steep time
Grind coarse, about like rock salt. One roaster grinds a notch finer to pull out more sweetness. On the counter, give it about 16 hours. One roaster calls anything from 14 to 18 fine and warns you off going past 20 to 24. A batch in the fridge needs longer, about 20 to 24 hours.
Making a batch
Weigh the coffee and the water. Tip the grounds into a big jar, pour in the water, and stir until you see no dry clumps. Put a lid on. Leave the jar on the counter out of the sun, or slide it into the fridge. Once the hours are up, strain it into a clean bottle and keep it sealed in the fridge.
Straining it clean
Strain it twice. A fine mesh strainer catches the big grounds, then a paper filter or a few layers of cheesecloth catches the silt. Paper gives you a cleaner cup, and cloth leaves more body. Expect less concentrate than the water you poured in. Wet grounds hold about 1.5 to 2 times their own weight in water.
Mixing a glass
Start with one part concentrate to one part water or milk, over ice. If it tastes thin, move to two parts concentrate to one part water. For a hot cup, mix one part concentrate with two parts hot water. Concentrate keeps longer than diluted cold brew, so mix one glass at a time.
