Understanding cold brew ratios
Cold brew ratios are expressed as coffee to water by weight. The two common styles are:
- Concentrate (1:4 to 1:5): 100 g coffee to 400–500 g water. You dilute this 1:1 with water or milk before drinking. Strong, almost syrupy on its own.
- Ready-to-drink (1:7 to 1:8): 100 g coffee to 700–800 g water. Drink it straight from the fridge with ice. Lighter, more delicate flavour.
If you're unsure which to make, start with 1:5 concentrate — it's the most flexible. You can dilute it as much or as little as you like, add it to milk, mix it into cocktails, or drink it straight over ice.
The right grind size for cold brew
Use a coarse grind — like cracked peppercorns or rough sea salt. Cold brew steeps for 12–24 hours. A coarse grind prevents over-extraction during that long contact time. If you grind too fine, the resulting coffee will be bitter and harsh even at low concentrations.
The difference between coarse and medium grind matters more in cold brew than almost any other method, because the long steep time magnifies even slight differences in extraction rate.
Steep time and temperature
In the fridge (4 °C): Steep for 18–24 hours. Cold temperatures slow extraction significantly.
At room temperature (20–22 °C): Steep for 12–14 hours. Faster extraction, slightly brighter flavour, but higher risk of sourness if left too long.
When in doubt, use the fridge. It's more forgiving and produces a consistently smooth result.
Common problems
Bitter or harsh
Over-extracted. Grind coarser, reduce steep time, or dilute more aggressively. If you steeped at room temperature, move to fridge steeping next time.
Weak or watery
Under-extracted. Increase your coffee dose (try 1:4 instead of 1:6), grind slightly finer (but still coarse), or extend the steep time by 4–6 hours.
Sour or vegetal
Very under-extracted. The water hasn't had enough contact time or the grind is too coarse. Steep longer or increase your ratio first before adjusting grind.