Cold brew is one of the most forgiving brewing methods — but the ratio matters more than most people realize. Too little coffee and the result is thin and watery. Too much and it becomes harsh and over-concentrated. The key decision is whether you are making a concentrate (to dilute later) or a ready-to-drink batch.

Cold Brew Ratios

Type Coffee:Water Ratio Example (grams) Notes
Concentrate 1:4 100g coffee / 400ml water Dilute 1:1 with water or milk before drinking
Concentrate (strong) 1:3 100g coffee / 300ml water For very strong concentrate or milk drinks
Ready-to-drink 1:8 100g coffee / 800ml water Drink straight over ice
Ready-to-drink (mild) 1:10 100g coffee / 1000ml water Lighter, more refreshing

Recommendation for beginners: Start with a 1:8 ratio ready-to-drink batch. It is the most forgiving and requires no dilution math.

Steep Time

Method Temperature Steep Time
Room temperature 68–72°F (20–22°C) 12–14 hours
Refrigerator 35–40°F (2–4°C) 16–24 hours

Room temperature steeping is faster. Refrigerator steeping is slower but produces a slightly smoother, less acidic result. Both methods work well.

Do not steep for more than 24 hours — the coffee can become bitter and over-extracted, especially at room temperature.

How to Make Cold Brew (Basic Method)

  1. Grind coffee coarse — similar to or slightly coarser than French press.
  2. Combine coffee and cold or room-temperature water in a jar or pitcher.
  3. Stir gently to make sure all grounds are saturated.
  4. Cover and steep at room temperature for 12–14 hours, or in the refrigerator for 16–24 hours.
  5. Strain through a fine mesh strainer, cheesecloth, or paper coffee filter.
  6. Store the strained cold brew in the refrigerator. It keeps well for up to two weeks.

Dilution Guide for Concentrate

If you made a 1:4 concentrate, dilute it before drinking:

Desired Strength Concentrate Diluent
Standard (like drip coffee) 1 part 1 part water
Lighter 1 part 1.5 parts water
Milk drink (latte-style) 1 part 1 part milk or oat milk
Over ice (accounts for melt) 1 part 0.75 parts water

Troubleshooting

Problem Likely Cause Fix
Weak, watery Too little coffee or too short steep Increase ratio or steep longer
Bitter, harsh Over-steeped or grind too fine Reduce steep time or coarsen grind
Muddy, gritty Grind too fine Use coarser grind; filter twice
Sour Under-extracted Steep longer or use slightly finer grind
Flat, dull Stale coffee Use fresher beans

Grind Size for Cold Brew

Use a coarse grind — similar to French press or slightly coarser. Fine grinds over-extract during the long steep time and make filtering difficult. See the Coffee Grind Size Chart for a visual reference.

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