If there is one number that decides whether your cold brew tastes amazing or just okay, it is the ratio — how much coffee you use compared to water. The good news? You do not need a scale, a calculator, or a coffee degree. The cold brew ratio is one of the simplest formulas in coffee, and once you know it, you can make a great batch every single time.
Use a 1:8 ratio (1 part coffee to 8 parts water) for ready-to-drink cold brew you can pour straight over ice, or a 1:4 ratio for a stronger concentrate you dilute with water or milk. By weight, that's about 1 gram of coffee per 8 grams of water (ready-to-drink) or per 4 grams (concentrate).
What “Ratio” Actually Means
A coffee ratio is just a comparison: parts coffee to parts water. When you see 1:8, it means 1 part coffee for every 8 parts water. A “part” can be any unit you like — cups, ounces, or grams — as long as you use the same unit for both. So 1 cup of grounds to 8 cups of water is 1:8. Easy.
If ratios are brand new to you, our coffee-to-water ratio guide explains the whole concept across every brewing method.
The Two Ratios You Need
Cold brew really comes down to two starting points, depending on how you like to drink it:
1:8 — Ready-to-Drink Cold Brew
This makes cold brew you can pour straight over ice and sip, no diluting needed. It is the simplest path for beginners. Example: 1 cup of coarse grounds to 8 cups of water.
1:4 — Cold Brew Concentrate
This makes a strong concentrate that you dilute before drinking — usually about half concentrate, half water or milk. Concentrate is handy because it takes up less fridge space and lasts a little longer. Example: 1 cup of coarse grounds to 4 cups of water.
If you are not sure which to make, start with a 1:4 concentrate. It is the most flexible — you can always add water to weaken it, but you cannot make a too-weak batch stronger after the fact.
A Simple Cold Brew Ratio Chart
Here are some no-math amounts to get you started. These use volume (cups), which is plenty accurate for cold brew:
| Style | Coffee | Water | Makes about |
|---|---|---|---|
| Ready-to-drink (1:8) | 1/2 cup grounds | 4 cups water | ~4 cups cold brew |
| Ready-to-drink (1:8) | 1 cup grounds | 8 cups water | ~8 cups cold brew |
| Concentrate (1:4) | 1 cup grounds | 4 cups water | ~4 cups concentrate |
| Concentrate (1:4) | 1.5 cups grounds | 6 cups water | ~6 cups concentrate |
If You Want to Use a Scale
A kitchen scale makes your ratio repeatable, but it is optional for cold brew. By weight, 1:8 means 1 gram of coffee for every 8 grams (8 ml) of water. So for a 1:8 batch with 100 g of coffee, you would use 800 g of water. For a 1:4 concentrate with 100 g of coffee, use 400 g of water. Weighing is the most consistent way to repeat a batch you loved.
How to Adjust to Your Taste
These ratios are starting points, not rules. Dial it in like this:
- Too strong or intense? Add more water (or milk) to the glass, or use a touch less coffee next time.
- Too weak or watery? Use a bit more coffee, or steep a few hours longer.
- Found your favorite? Write the amounts down so you can make it again exactly.
Ratio and steep time work together. If you increase your coffee a lot and steep for 24 hours, you may end up with something very strong and possibly bitter. Change one thing at a time so you know what made the difference.
Don't Forget the Grind
Ratio matters, but so does grind. Even a perfect 1:8 ratio will taste muddy if your coffee is ground too fine, because fine grounds over-extract during the long steep. Aim for a coarse grind, like raw sugar or coarse sea salt. See our guide to coffee grind sizes for a visual.
Frequently Asked Questions
What is the best cold brew ratio for beginners?
Start with 1:8 (1 part coffee to 8 parts water) for ready-to-drink cold brew, or 1:4 for a concentrate you dilute. Both are forgiving — adjust to taste from there.
What's the ratio for cold brew concentrate?
About 1:4 — for example, 1 cup of coarse grounds to 4 cups of water. Dilute the finished concentrate roughly 1:1 with water or milk before drinking.
Do I need to weigh my coffee for cold brew?
No. Cold brew is forgiving enough that measuring by the cup works fine. A scale just makes it easier to repeat a batch exactly.
- Use 1:8 for ready-to-drink cold brew, 1:4 for concentrate you dilute.
- A “part” can be cups, ounces, or grams — just keep the unit the same for coffee and water.
- Concentrate (1:4) is the most flexible starting point — you can always add water.
- Adjust one thing at a time (ratio or steep time) to find your taste.
- Grind coarse, or even the right ratio will taste muddy.
That is the whole formula. Pick a ratio, grind coarse, and steep — then tweak to taste. Ready to put it into practice? Follow our step-by-step cold brew guide, or start with the complete beginner's guide to cold brew.
☕ About the Author
Greg Rathbone is the founder of HomeCoffeeBeginner.com. He started this site after realizing most coffee advice online assumes you're already an expert. Every guide here is written for total beginners and tested in his own kitchen — no jargon, no snobbery.