Free Coffee Tool

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Cold Brew Ratio Calculator

Enter your batch size and strength to get the exact coarse-ground coffee and water for cold brew concentrate or ready-to-drink coffee.

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Calculate your cold brew batch

oz
1:5.0
Strong (1:4)Light (1:8)

Coarse-ground coffee

Standard Conc.

189g

Cold water

946ml

Water in oz

32.0oz

Steep

12-24 hrs

Coffee to water by weight

Batch timeline

Combine

stir well

Steep

12-24 hrs

Filter

then dilute

Strength

StrongLight

Next: Dilute lightly to taste, or drink over ice as-is for a bolder glass. A longer steep tastes stronger, so change steep time before the ratio.

The math behind the calculator

The calculator applies water (ml) = coffee (g) × ratio at a 1:4–1:8 range depending on the style you pick — concentrate at 1:4–1:5, ready-to-drink closer to 1:8. That range runs much higher than hot brewing methods because cold water extracts far more slowly, so a much longer steep and a stronger ratio are both needed to reach a drinkable strength.

Concentrate is typically diluted roughly 1:1 after brewing, which is why the calculator's concentrate output is deliberately stronger than what you'd drink straight — the dilution step is a separate decision made at serving time, not baked into the brew ratio itself.

How to use the result

  1. 1Pick concentrate or ready-to-drink.
  2. 2Combine coarse grounds and cold water, steep 12-24 hours.
  3. 3Filter, then dilute concentrate to taste.

Common mistakes

  • Grinding too fine: over-extraction and a clogged filter.
  • Adding more grounds when a longer steep is what a thin batch needs.
  • Skipping the second paper-filter pass for a cleaner concentrate.

Get the Coarse Grind Cold Brew Needs

Too fine a grind over-extracts during a 12-24 hour steep and clogs your filter. These burr grinders make it easy to dial in a consistent coarse grind for cold brew.

Frequently Asked Questions

Quick answers before you buy.

1:4 to 1:5 is the standard range for a concentrate you'll dilute before drinking — 1:4 makes a stronger concentrate, 1:5 (the classic Toddy-style ratio) is a bit more forgiving to dilute.

If you want to drink it straight over ice with no dilution, brew at a lighter 1:8 instead.

12 to 24 hours, depending on grind size, water temperature, and how strong you want the result.

Room temperature extracts faster than a refrigerator, so 12-16 hours at room temperature is roughly equivalent to 18-24 hours in the fridge.

Start tasting around the low end and extend if it's still weak.

Cold water extracts fewer of the acidic and bitter compounds that heat pulls out quickly, while still extracting sweetness and body over the long steep time.

That's a property of temperature and time, not the ratio — using more or less coffee changes strength, not acidity level.

Yes, similar to French press — a coarse, uniform grind is important.

A finer grind increases surface area and can over-extract during a 12-24 hour steep, plus it makes the concentrate harder to filter cleanly afterward.

A US quart is about 946 ml.

At a 1:8 ready-to-drink ratio that's roughly 118 g of coffee, and at a 1:5 concentrate about 189 g.

Enter your batch size above for exact amounts.

Concentrate is commonly kept refrigerated for up to about two weeks, and diluted ready-to-drink for a shorter time.

Store it sealed and cold, and discard it if it smells or tastes off.

Verify with your own sensory check rather than a fixed date.

Keep reading: more guides on the same topic.

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