Cold Brew Calculator
Enter the coffee, the brew ratio and how strong you want it in the glass. Get the water to add, how much the grounds will keep, the real yield, and how to dilute.
about 18 tbsp, extra-coarse grind
1:4-1:6 concentrate; 1:8-1:12 ready to drink
What you want in the glass
12-18 h fridge; 8-12 h room temp
Water to add
500 ml
100 g × 5
Held by the grounds
200 ml
about 2× the coffee weight
Concentrate yield
300 ml
10 fl oz after straining
Dilute each part with
0.6 parts
water or milk → 480 ml of drinks
Yield by ratio for 100 g of coffee
| Ratio | Water (ml) | Yield (ml) | Dilute 1 : | Drinks at 1:8 (ml) |
|---|---|---|---|---|
| 1:4 | 400 | 200 | 1 | 400 |
| 1:5 | 500 | 300 | 0.6 | 480 |
| 1:6 | 600 | 400 | 0.33 | 533 |
| 1:8 | 800 | 600 | — | 600 |
| 1:10 | 1000 | 800 | — | 800 |
| 1:12 | 1200 | 1000 | — | 1000 |
Yield = water − about 2 g of water per gram of coffee that stays in the wet grounds (press gently to recover a little more). Dilution to reach 1:8 = 8 ÷ 5 − 1 parts liquid per part concentrate. Steep 16 h, strain through a paper filter, keep refrigerated up to two weeks.
Worked example
100 g coffee at 1:5 takes 500 ml water. The grounds keep about 200 ml, so you strain off 300 ml of concentrate. To drink it at 1:10, add 1 parts water or milk per part concentrate, which stretches it to 600 ml of finished drinks, or about 2.5 eight-ounce glasses.
Batch sizes at 1:5, drunk at 1:10
| Coffee | Water | Concentrate | Finished drinks | 8 oz glasses |
|---|---|---|---|---|
| 50 g | 250 ml | 150 ml | 300 ml | 1.3 |
| 100 g | 500 ml | 300 ml | 600 ml | 2.5 |
| 150 g | 750 ml | 450 ml | 900 ml | 3.8 |
| 200 g | 1000 ml | 600 ml | 1200 ml | 5.1 |
| 300 g | 1500 ml | 900 ml | 1800 ml | 7.6 |
| 450 g | 2250 ml | 1350 ml | 2700 ml | 11.4 |
Concentrate or ready to drink?
Concentrate is denser to store and lets each person set their own strength and milk, at the cost of one more step. Ready-to-drink at 1:8 to 1:10 uses more water and jar space but is grab-and-pour and less likely to be accidentally strong. Both use the same coffee per finished glass; only the water timing differs. Use a coarse grind and a paper filter after the mesh for a clean cup, and keep it cold.
Frequently Asked Questions
What is the best cold brew ratio?
1:4 to 1:6 by weight for a concentrate you dilute, 1:8 to 1:12 for something you drink straight. 100 g of coarse coffee with 500 g of water (1:5) makes a concentrate that, cut one-to-one with water or milk, lands around 1:10 in the glass. Cold water extracts slowly, which is why cold brew ratios are so much stronger than the 1:16 of hot coffee.
How long should cold brew steep?
12 to 18 hours in the fridge, or 8 to 12 at room temperature. Under 8 hours it is thin and sour; past 24 it turns woody and bitter. Coarser grinds need the longer end. Steep time barely changes caffeine after 12 hours, so go by taste.
Why do I get less cold brew than the water I put in?
The grounds hold on to roughly twice their own weight in water: 100 g of coffee keeps about 200 ml, so 500 ml in becomes about 300 ml out. Pressing the grounds recovers some but pushes fine sediment through. Plan the ratio around what you want to drink, not what you pour in.
How do I dilute cold brew concentrate?
Divide the drinking ratio by the brew ratio and subtract one. Concentrate brewed at 1:5, drunk at 1:10, needs 10 ÷ 5 − 1 = 1 part water per part concentrate. At 1:4 brewed and 1:12 drunk it is 2 parts. Ice counts as water once it melts, so pour a little stronger over ice.
How long does cold brew keep?
Concentrate keeps about two weeks refrigerated in a sealed jar; diluted cold brew is best within a week. It has no heat-driven staling, but it does slowly ferment and lose brightness, so the second week tastes flatter than the first.
These tools use baker's percentages, salt-by-weight brining, coffee ratios by weight and the USDA roasting and thawing tables, all stated on each page. They are starting points for your kitchen, your flour and your oven: taste the brine, watch the dough, and always cook poultry to 165°F on a thermometer.