WhiskMath

Cold Brew Calculator

Get the exact ground coffee, water, and steep time for cold brew concentrate or ready-to-drink.

g

The finished amount you want to end up with. 1 ml of water is about 1 g.

Strength
Ground coffee
83.3 g
1:5 ratio · coarse grind
Brewing water
416.7 g
by weight (≈ ml)
Steep time
16 hrs
in the fridge
  • Use a coarse grind — fine grounds make cold brew muddy and hard to filter.
  • Combine the coffee and water, stir, and steep for 16 hours in the fridge.
  • When serving, dilute 1:1 — add about 500 g of water or milk to the strained concentrate.
  • Strain through a fine mesh or paper filter, then store the brew in the fridge for up to two weeks.
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How to use this calculator

  1. Enter your desired output volume

    Type how much finished cold brew you want to end up with, in grams. 1 ml of water is about 1 gram.

  2. Choose concentrate or ready-to-drink

    Concentrate uses a 1:5 ratio and is diluted before serving; ready-to-drink uses a 1:15 ratio and is served as brewed.

  3. Read the coffee, water, and steep time

    The calculator shows the coarse-ground coffee, the brewing water, and how long to steep in the fridge.

  4. Steep, strain, and serve

    Combine, steep for the listed time, strain through a fine filter, and — for concentrate — dilute 1:1 to serve.

Recommended gear

As an Amazon Associate, WhiskMath earns from qualifying purchases. These picks don't cost you anything extra.

AeroPress Original Coffee Maker

Handy for small cold brew batches and easy to press the grounds clean.

$40

View on Amazon

Hario V60 Ceramic Coffee Dripper, Size 02

A paper-filter dripper that strains cold brew crystal-clear after steeping.

$25

View on Amazon

Cold brew strength reference

StrengthRatioSteep timeGrind
Concentrate (diluted 1:1 to serve)1:516 hoursCoarse
Ready to drink (no dilution)1:1518 hoursCoarse

Ratios are coffee-to-water by weight. 1 ml of water is about 1 gram.

Tips & best practices

  • Always use a coarse grind — it's the difference between clean cold brew and a muddy cup.
  • Weigh your coffee and water; cold brew is unforgiving of guessed measurements.
  • Steep in the fridge, not on the counter, for a cleaner and safer result.
  • Strain twice if needed — once through mesh, then through a paper filter for a crystal-clear brew.
  • Make concentrate if you want flexibility: dilute it with water, milk, or over ice however you like.
  • Label your jar with the brew date — cold brew is best within two weeks.

Frequently asked questions

What is the best ratio for cold brew?
It depends on whether you're making concentrate or ready-to-drink. Concentrate uses a 1:5 coffee-to-water ratio by weight and is diluted before serving, while ready-to-drink cold brew uses a 1:15 ratio and is served straight.
How long should cold brew steep?
Steep concentrate for about 16 hours and ready-to-drink for about 18 hours, both in the fridge. Steeping much longer than that can pull out bitter, woody flavors.
What grind should I use for cold brew?
Use a coarse grind, similar to what you'd use for a French press. Fine grounds make the brew muddy, slow to filter, and over-extracted.
How do I dilute cold brew concentrate?
Dilute concentrate 1:1 — equal parts concentrate and water or milk. The calculator tells you exactly how much dilution liquid to add for your batch size. Adjust to taste from there.
Should I brew cold brew in the fridge or at room temperature?
The fridge is the safer, more consistent choice. Room-temperature steeping is faster but extracts more aggressively and carries a higher risk of off-flavors, so chilled steeping is the standard method.
How long does cold brew last?
Stored in the fridge, strained cold brew keeps well for up to about two weeks. Concentrate tends to hold its flavor a little longer than ready-to-drink because it's less exposed to dilution.
Does 1 ml of water equal 1 gram for cold brew?
Yes, for brewing purposes water's density is close enough to 1 gram per milliliter that you can measure by either. Weighing on a scale is still the most accurate way to hit the ratio.
Why is my cold brew weak or watery?
The usual causes are too coarse a measurement, too little coffee, or not steeping long enough. Double-check you're weighing to the ratio, and make sure concentrate gets its full steep before you dilute it.

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Sources: Specialty Coffee Association cold brew brewing guidance; Standard cold brew recipe references.

Results are estimates for informational use. For food safety, always confirm meat doneness with a thermometer against current USDA guidance. WhiskMath does not provide medical or dietary advice.