Cold Brew at Home: Smooth, Low-Acid, and Simple

How to make a batch of smooth cold-brew concentrate with nothing but coffee, water, and time.

6 min read

Cold brew is the most patient method of all, and the most hands-off. Instead of using heat to extract coffee quickly, it uses time — steeping coarse grounds in cool water for many hours. The result is naturally sweet, smooth, and notably lower in acidity than hot coffee, which is why people who find regular coffee harsh often love it. The trade-off is that you have to plan ahead.

Brew a concentrate, then dilute

The most flexible approach is to brew a strong concentrate and dilute it later. A 1:8 ratio works well for concentrate — one gram of coffee for every eight grams of water, for example 100 grams of coarse coffee to 800 grams of cold water. You will dilute the finished concentrate roughly one-to-one with water, milk, or ice when you serve it, which effectively brings it to a drinkable strength.

Grind and steep

• Grind coarse, like French press. Fine grounds make cold brew cloudy, over-extracted, and hard to filter.
• Use cool or room-temperature water and stir to make sure every ground is saturated.
• Steep 12 to 18 hours. Around 12 hours gives a brighter result; closer to 18 gives a deeper, rounder one.
• Steep on the counter or in the fridge — fridge steeps a little slower and is more forgiving of longer times.

Straining

1. Pour the brew through a fine mesh strainer to catch the bulk of the grounds.
2. Strain a second time through a paper filter or a clean cloth to remove the fine sediment.
3. Store the concentrate in a sealed jar in the fridge; it keeps well for up to two weeks.

Serving

To serve, fill a glass with ice, pour in concentrate, and top with an equal part of water or milk — then adjust to your taste. Because you are diluting a concentrate, your final strength is really two ratios working together: the steep ratio and the dilution ratio. Saving the recipe means you can reproduce both exactly, scale a bigger batch for a gathering, and never guess at how much water you added last time.

Cold brew is the one method where doing nothing for twelve hours is the technique. Get the ratio and the grind right, and patience does the rest.