How to Make Cold Brew

Cold brew has a reputation for being foolproof, which is almost true. It is hard to make undrinkable cold brew. It is surprisingly easy to make mediocre cold brew — thin, muddy, or flat — and most homemade batches land there because of three fixable mistakes: measuring by volume, grinding too fine, and guessing at time.

Here is the method we use for every control batch on this site. It requires no special equipment and produces a concentrate better than most of what we've scored out of 100.

What you need

• A large jar or pitcher. Anything with a liter or more of capacity. A dedicated brewer is nice; it is not necessary. (What we actually use lives on the gear page.)
• A kitchen scale. Non-negotiable. Coffee scoops lie by up to 30 percent depending on grind and roast. A $15 scale ends the guessing permanently.
• Coarsely ground coffee. Sea-salt texture. More on why in the grind size guide.
• Cold, filtered water. Your brew is 85 percent water. If the tap tastes like a swimming pool, so will the coffee.
• A strainer and paper filters. A fine-mesh sieve for the first pass, a paper filter (or a pour-over cone) for the second.

The method — 1-liter batch

1. Weigh 200 g of coarsely ground coffee into the jar.
2. Add 1,000 g of cold, filtered water (1,000 ml — water conveniently weighs 1 g per ml). That's a 1:5 ratio, which produces a concentrate. Why 1:5 and what the alternatives do is covered in the ratio guide — or skip the reading and use the ratio calculator.
3. Stir until every ground is wet. Dry pockets of coffee brew nothing. Thirty seconds of stirring is the highest-value labor in the whole process.
4. Cover and steep 14–18 hours at room temperature, or 18–24 hours in the fridge. Fridge extraction runs slower; both work. The trade-offs are in the steep time guide.
5. Strain twice. First through the mesh sieve to pull the bulk of the grounds, then through a paper filter. The second pass is the difference between silky and silty, and skipping it is the most common shortcut people regret.
6. Bottle and refrigerate. A sealed glass bottle keeps the concentrate honest for 7–10 days. It's at its best in the first week; after that it slides toward cardboard.

Expect a yield of roughly 600–650 ml of concentrate — the grounds keep about twice their weight in water, and that water is gone. You planned for this, because you read step 2.

Drinking it

This is concentrate. Cut it roughly 1:1 with cold water or milk over ice. Stronger or weaker to taste — the point of making concentrate is that one batch serves the person who drinks it black and the person who essentially orders a milkshake.

Troubleshooting

• Bitter or harsh. Ground too fine, steeped too long at room temperature, or both. Coarsen the grind first; it's the usual culprit.
• Watery. Ratio too thin or grind too coarse to extract. Check your scale before you blame the beans.
• Sour or grassy. Under-extracted: steep longer, or grind one step finer.
• Muddy or gritty. You skipped the paper filter. We watched you do it.

The one-sentence version

200 g coarse coffee, 1,000 g cold water, 16 hours on the counter, strain twice, cut 1:1, drink within a week — and weigh everything, because the scale is the whole trick.