12 or 18 hours for cold brew?

12 hours at room temperature gives a balanced cup. Beyond that, or in the fridge, push toward 18-24 hours — but extract past 18 hours starts turning bitter.

Is cold brew stronger than espresso?

By caffeine-per-ounce it's roughly comparable, but cold brew is smoother and less acidic, so people drink it faster and in bigger volumes. Diluted 1:1 it's about filter-strength.

Brew guide · Cold brew · Updated 2026-08-17

Cold Brew Coffee Recipe (UK, Metric-First)

The definitive cold brew recipe — one ratio, twelve hours, no bitterness. Settles the 1:8 vs 1:15 debate once and for all.

Ratio: 1:8 concentrate (100 g coffee → 800 g water)

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Dose18 g

Water288 g

1:16 ratio · 6.25% strength

GrindFine

Salt-like · classic pour-over

00:00

Target ≈ 2:45

Grind size visual30% screen retention

FineCoarse

Step by step

1
Grind coarse(0:00)
Grind 100 g of coffee coarse — the biggest setting on your grinder, like breadcrumbs. Cold water extracts slowly, so coarse grounds prevent over-extraction and chalky bitterness.
2
Add coffee and cold water(0:00 - 0:05)
In a large jar or cafetière, add the grounds and 800 g of cold filtered water. Stir well to wet every particle. Use a 1:8 ratio for concentrate — it dilutes later.
3
Steep for 12 hours(12 hours)
Cover and leave at room temperature for 12 hours. Beyond 18 hours it starts pulling bitter tannins. Fridge-steep if you prefer a slightly softer, cleaner cup — allow 18 hours.
4
Filter and dilute(12:00 +)
Strain through a fine mesh or paper filter to remove all fines. The concentrate is 1:8 — dilute with an equal part of water or milk (1:1) before drinking over ice.

Barista tips

Strain twice: once through a sieve, then through a paper filter for a clean finish.
Cold brew keeps in the fridge for up to two weeks.
Use a darker roast for chocolatey body; light roasts stay fruity and bright.
Don't steep longer than 18 hours — bitterness creeps in fast after that.