The right cold brew ratio depends on one decision: do you want a concentrate to dilute later, or a ready-to-drink batch to pour straight over ice? A concentrate runs roughly 1:4 to 1:8 coffee to water by weight; a ready-to-drink cold brew runs roughly 1:15 to 1:17. Get that choice right and the rest is just measuring, grinding coarse, and steeping. This guide is the ratio spoke. For the full step-by-step method, see how to make cold brew coffee.
What the cold brew ratio actually means
A coffee-to-water ratio is simply how much ground coffee you use for a given amount of water, written as 1:X. A 1:5 ratio means one part coffee to five parts water by weight, so 200 g of coffee to 1,000 g (1 litre) of water. The bigger the second number, the weaker and more diluted the brew. Cold brew sits at the strong end of the scale compared with hot methods because cold water extracts slowly and gently, so you compensate with more coffee, a coarse grind, and a long steep. If you want the wider picture across espresso, drip, and pour-over, our coffee brewing ratios guide covers the whole family.
The key thing to internalise: there is no single correct cold brew coffee ratio. There are two useful ones, and they exist for two different routines.
The two ratios that matter: concentrate vs ready-to-drink
Almost every cold brew recipe you will see is really one of these two. Pick based on how you like to serve it, not on which sounds "better."
Concentrate (1:4 to 1:8)
A concentrate is brewed strong on purpose so you can cut it down later. Most home brewers land near 1:5: about 200 g of coarse coffee to 1 litre of water. It keeps well in the fridge for up to two weeks, stores in less space, and lets you make a small cup or a big one on demand. The catch is that you must dilute it before drinking, or it will taste intense and almost syrupy.
Ready-to-drink (1:15 to 1:17)
A ready-to-drink batch is brewed at roughly drinking strength so you can pour it straight over ice with no maths. Around 1:16 (say 60 g of coffee to 1 litre of water) lands close to a strong drip coffee. It is simpler and friendlier for serving a group, but it takes up more fridge space per cup of actual coffee and gives you less room to adjust.
Cold brew coffee to water ratio table
Use this as your starting point, then nudge to taste. All ratios are by weight (1 g of water is 1 ml, which makes the maths easy).
| Goal | Cold brew ratio (coffee:water) | Example | Result and how to serve |
|---|---|---|---|
| Strong concentrate | 1:4 to 1:5 | 200–250 g coffee : 1 L water | Very strong. Dilute 1:1 with water or milk before drinking. |
| Medium concentrate | 1:6 to 1:8 | 125–165 g coffee : 1 L water | Strong but flexible. Dilute roughly 1:1 or a little less. |
| Ready-to-drink | 1:15 to 1:17 | ~60 g coffee : 1 L water | Drink as is over ice. Add milk to taste; no dilution needed. |
How to measure your cold brew coffee to water ratio
The most repeatable way is by weight on a kitchen scale, because volume scoops of ground coffee vary a lot with grind and settling.
- Decide your batch size by water. A litre of water is a friendly starting amount.
- Pick your ratio from the table. For a 1:5 concentrate with 1,000 g water, you need 200 g of coffee.
- Weigh the coffee, grind it coarse, and combine it with the cold water. Make sure all the grounds are wet.
- Steep, then strain. Decant the liquid off the grounds so extraction stops cleanly.
No scale? A rough volume guide: a standard 1:8-ish batch is about one cup (roughly 85–100 g) of coarse grounds to four cups (about 950 ml) of water. It is less precise, but it gets you in the zone. A dedicated coffee concentrate can be brewed even stronger if you plan to dilute heavily.
How grind and steep time change the ratio
Ratio is one of three levers. Grind size and steep time pull on the same rope, so think of them together.
- More coffee or a longer steep makes it stronger. Pushing from 1:8 to 1:5, or from 12 hours to 18, both increase extraction and body.
- A coarse grind is non-negotiable. Cold brew wants a grind like coarse sea salt. Too fine and the water over-extracts during the long soak, turning the brew bitter and muddy no matter how careful your ratio is. Our best grind for cold brew coffee guide goes deeper.
- Steep about 12 to 24 hours. Twelve hours gives a brighter, lighter cup; 18 to 24 gives more strength and depth. Past 24 hours you mostly pull harsh, astringent compounds, so longer is not always better.
Because these three interact, change one variable at a time. If you double the coffee and the steep at once, you will not know which made the difference.
How to dilute a concentrate to taste
If you brewed a concentrate, dilution is where you set the final strength. The cafe default is 1:1 (one part concentrate to one part water or milk), which lands near a strong, smooth standard cup.
- 1:1 with water — standard strength, clean and balanced.
- 1:1 with milk — creamy, latte-like; dairy or oat, almond, and coconut all work.
- 2:1 (more concentrate) — bolder, for a stronger hit.
- 1:2 (more water) — lighter and milder for a long, easy-sipping glass.
Build the drink over ice and taste as you pour. You can always add more water; you cannot take it out. Because it is made with real coffee, cold brew is not caffeine-free, so dilution also softens the caffeine hit per glass.
Troubleshooting your cold brew ratio
Most problems trace back to one of the three levers.
- Too weak or watery? Use more coffee (move toward 1:5), steep longer (toward 18–24 hours), or dilute the concentrate less.
- Too bitter or harsh? Grind coarser, shorten the steep, or use less coffee. Over-extraction from a fine grind is the usual culprit, not the ratio itself.
- Muddy or gritty? Your grind is too fine, or you did not strain cleanly. Use a coarse grind and filter through a fine mesh or paper.
- Flat or dull? Try fresher beans and a slightly higher coffee dose; stale coffee tastes thin no matter the ratio.
The takeaway
Choose your routine first. If you want flexibility and fridge space, brew a 1:4–1:8 concentrate and dilute 1:1 to serve. If you want zero fuss, brew a 1:15–1:17 ready-to-drink batch and pour it straight. Keep the grind coarse and the steep between 12 and 24 hours, then fine-tune by taste. Once your ratio feels dialled in, walk through the complete cold brew method to lock in every step.