Cold Brew Concentrate Calculator
Work out how much coffee to steep for a cold brew batch, then dial in your dilution for the strength you want.
Steep 12 to 18 hours in the fridge or at cool room temperature, then strain through a filter or fine mesh before diluting.
How it works
Cold brew is normally steeped as a concentrate, then diluted before drinking, so this tool handles both steps. First, enter your batch water and a brew ratio (1:5 is a common starting point) to get the coffee grams for the steep. Then set a dilution amount, how many parts of water you add per one part of concentrate when you pour a glass, to see the final drinking strength.
Worked example: a 1000 ml batch at a 1:5 brew ratio needs 200 g of coarse-ground coffee (1000 divided by 5). If you then dilute that concentrate 1:1 with water when serving, multiply 5 by (1 plus 1) and you get an effective ratio of 1:10, noticeably stronger than drip coffee's usual 1:16. A lighter 1:4 concentrate diluted 1:1.5 lands at the same 1:10 final strength, showing there's more than one path to the same cup.
FAQ
Why steep cold brew for so long?
Cold water extracts coffee much more slowly than hot water, so it takes 12 to 18 hours instead of a few minutes to pull out enough flavor. That slow, cool extraction is also why cold brew tastes smoother and less acidic than hot-brewed coffee left to cool.
What grind size should I use?
Coarse, similar to French press. A fine grind over that long a steep tends to over-extract and turns bitter, and it's harder to filter cleanly out of the batch.
How long does the concentrate keep?
Strained cold brew concentrate holds up in the fridge for about 1 to 2 weeks in a sealed container. Dilute only what you plan to drink that day, since diluted cold brew doesn't keep as well as the concentrate.
Can I dilute with milk instead of water?
Yes, plenty of people do. The dilution field here assumes water so the ratio stays comparable to drip coffee, but swapping some or all of that dilution for milk just changes the drink, not the underlying steep.
For the full walkthrough, see how to make cold brew coffee at home, homemade cold brew concentrate, and vanilla sweet cream cold brew at home for a serving idea.