I am Michael Klemmer, a 20-year Army logistics officer turned coffee roaster, and cold brew concentrate is the most forgiving coffee you can make. No machine, no skill, hard to screw up. Here is the exact ratio and method I give people who ask.
What Is Cold Brew Concentrate?
Cold brew concentrate is coffee steeped in cold water for many hours, then strained to a strong base you dilute before drinking. It is not just cold coffee. It is a different, smoother extraction.
Because it never touches heat, cold brew pulls less acidity and bitterness out of the beans. The result is smooth, naturally sweet, and easy on the stomach.
Making it as a concentrate means one batch lasts you a week or more. You dilute a little at a time, hot or iced.
| Step | What To Do |
|---|---|
| Ratio | 1 part coffee to 4 parts cold water, by weight |
| Grind | Coarse, like coarse sea salt |
| Steep | 12 to 18 hours, room temp or fridge |
| Strain | Fine mesh, then paper filter or cloth |
| Serve | Dilute concentrate ~1:1 with water or milk, add ice |
| Store | Sealed in the fridge, up to 2 weeks |
What Coffee-to-Water Ratio Should You Use?
Use a 1:4 ratio by weight for concentrate. That is one part coffee to four parts cold water, for example 250 grams of coffee to 1000 grams of water.
Combine the grounds and cold, filtered water in a jar, stir to wet everything, and cover it.
Steep 12 to 18 hours at room temperature or in the fridge. Longer is stronger. Then strain through a fine mesh and a paper filter or a cloth.
What Grind and Roast Work Best?
Use a coarse grind, like coarse sea salt, and a medium-dark or dark roast. Fine grounds make the concentrate muddy and over-extracted, and cold water favors bolder roasts.
A coarse grind keeps the brew clean and makes straining easy. Anything too fine slips through the filter and turns gritty.
Dark roasts cut through milk and ice without disappearing, which is why they are the standard for cold brew and iced lattes.
How Long Does Homemade Cold Brew Concentrate Last?
Stored sealed in the fridge, cold brew concentrate keeps its flavor for up to two weeks. Diluted cold brew is best within a few days.
Keep the concentrate in a sealed jar or bottle. Because it is strong and refrigerated, it holds up far longer than a pot of hot coffee.
To serve, mix the concentrate roughly one to one with water or milk, then add ice. Adjust to taste from there.
A bold roast makes the best cold brew.
Cold brew rewards a dark, full-bodied coffee because cold water pulls less flavor than hot. 15W40 has the body and depth to come through smooth and strong over ice.
Shop 15W40 →Frequently Asked Questions
What is the best ratio for cold brew concentrate?
A 1:4 ratio by weight, one part coffee to four parts cold water, gives you a strong concentrate you dilute before drinking. For ready-to-drink cold brew rather than concentrate, use about 1:8. Weighing is more accurate than measuring by scoops.
How long should cold brew steep?
Steep cold brew concentrate for 12 to 18 hours. Under 12 hours it tends to taste weak and sour; past about 20 hours it can turn woody and over-extracted. Twelve to eighteen hours is the reliable window, with longer giving a stronger result.
Can you use any coffee for cold brew?
You can, but a coarse-ground medium-dark or dark roast works best. Cold water extracts less than hot, so bolder roasts come through smoother and stronger. A fine grind makes the brew gritty and hard to strain, so grind coarse.
How do you dilute cold brew concentrate?
Start at about one part concentrate to one part water or milk, then adjust to taste. Add ice after diluting. Some people like it stronger and use less water. Because you control the dilution, one batch of concentrate can serve it weak or strong.
Does cold brew have more caffeine?
Cold brew concentrate is high in caffeine because of the high coffee-to-water ratio and long steep. Once you dilute it to drink, a serving is roughly comparable to regular coffee, though often a little stronger. Go easy until you know how your batch hits.
Good coffee should not be complicated. Neither should buying it.
