What ratio for cold brew coffee?
Quick answer
For concentrate, use 1:8 by weight — e.g. 60 g coffee to 480 ml cold water. Steep 12–18 hours in the fridge, strain, then dilute 1:1 with water or milk before drinking. Ready-to-drink cold brew is closer to 1:12–1:15.
What you need
- Container — a 1-liter mason jar, a French press, or any vessel that holds liquid and can be covered. Wide-mouth mason jars are easiest to clean.
- Scale — measuring by weight is more consistent than scoops.
- Grinder — set to extra coarse (like coarse sea salt). Pre-ground works in a pinch; just use coarser than you'd use for drip.
- Filter — a fine-mesh strainer lined with a paper coffee filter, a cheesecloth, or just the French press plunger. Paper filters give the clearest result.
- Storage pitcher — cold brew keeps up to 2 weeks in the fridge once strained.
Grind size
Extra coarse is the right target. Think coarse sea salt or roughly twice the size of a typical drip grind. Here's why: cold water extracts slowly. A fine grind that's great for drip will over-extract during a 14-hour steep and turn bitter and muddy. An extra coarse grind controls extraction rate, cuts sludge, and makes filtering much easier.
If you only have pre-ground coffee labeled "drip grind," it will still work — reduce steep time to 10–12 hours and filter twice.
Step by step
- Coarse grind — extra coarse reduces sludge.
- Combine coffee and cold filtered water in a jar.
- Steep 12–18 h refrigerated; stir once if you like.
- Filter through mesh and paper for clarity.
- Dilute concentrate 50/50 for a standard cup over ice.
Cold brew concentrate vs ready-to-drink ratios
Most home recipes make concentrate, which you dilute before drinking. The distinction matters because it affects how much coffee you actually need to buy.
Concentrate (1:4 to 1:8): Using 1 part coffee to 4–8 parts water gives a strong, syrupy brew. The 1:4 ratio produces a very intense concentrate — use it when you want a smaller-volume batch or plan to add a lot of milk. The 1:8 ratio (recommended here) is the most practical: strong enough to dilute 1:1 and taste like a full-flavored cup, but not so intense that it's unpleasant if you accidentally drink it less diluted.
Ready-to-drink (1:12 to 1:15): Brewing at this ratio means you can pour and drink straight from the fridge without diluting. It's convenient for batch brewing in a larger container (think 2-liter pitchers). The trade-off is that it takes up more fridge space and uses more water per gram of coffee.
Dilution guide for concentrate:
- 1:1 with water → standard cold brew over ice
- 1:1 with milk or oat milk → cold brew latte
- Add a splash of concentrate to sparkling water → cold brew fizz
- Straight over ice (no dilution) → very strong, use if you like that
The easiest way to scale your batch size is the ratio calculator.
Troubleshooting
Why is my cold brew weak? The three most common causes: steep time too short (under 10 hours), grind too coarse (ground for percolator or French press and used at 1:8 concentrate ratio), or over-diluted at the end. Fix: steep a full 14–16 hours, confirm your grind is extra coarse not medium, and dilute 1:1 not 1:2.
Why is it bitter or harsh? The grind is too fine, or the steep time was too long (over 20 hours). Fine grinds extract tannins quickly even in cold water. Fix: grind coarser and aim for the 12–16 hour window.
Why is my cold brew muddy or gritty? Grind too fine, or you skipped the paper filter step. Fix: double-filter — mesh strainer first, then paper filter. If you used a French press, plunge slowly and filter again through paper.
How long does it keep? Strained cold brew concentrate keeps up to 2 weeks refrigerated. If it starts tasting flat or slightly sour before that, your container probably wasn't fully clean. Rinse your jar with hot water before each batch.
Cold brew still needs normal fridge discipline. For broader kitchen timing, use a food storage time guide (opens in a new tab) when you're unsure how long prepared food or drinks should sit before you toss them.
Can I make it at room temperature? Yes. Room-temp cold brew steeps faster (8–12 hours) because slightly warmer water extracts more readily. The flavor is comparable but slightly less clean than fridge-steeped. Don't leave it out longer than 12 hours.
Common questions
Cold brew vs iced coffee? Cold brew steeps cold hours; iced coffee is hot-brewed then chilled. Different flavor. Read cold brew vs iced coffee.
Why is my cold brew weak? Steep time too short, grind too coarse, or over-diluted.
Caffeine in cold brew? Concentrate is strong before dilution — adjust dose if sensitive.
Calculate batch size in the ratio calculator.