Cold Brew Ratio: Concentrate and Ready-to-Drink, by Weight
The cold brew ratio by weight: 1:5 for concentrate and 1:12 to drink straight, with coffee per gallon, steep times, grind, filtering, food safety and a recipe card that scales from 1 to 30 gallons.
In this post
The short answer: for cold brew concentrate, use 1 part coarse-ground coffee to 5 parts water by weight, steep 12 to 18 hours at room temperature, then dilute it 1:1 to serve. For cold brew you drink straight, use 1:12. By volume, 1:5 is about 1⅔ lb of coffee per gallon of water.
Weigh the coffee and the water. Scoops and cups vary with the grind and the roast; a scale makes every batch taste the same, and it is the only way to scale a recipe from a jar to a 20 gallon kettle.
Cold brew ratios at a glance
| Style | Coffee : water by weight | How to serve |
|---|---|---|
| Concentrate, strong | 1:4 | Dilute 1:2 or 1:3; the most drinks per gallon stored |
| Concentrate, standard | 1:5 | Dilute 1:1 with water or milk |
| Concentrate, light | 1:6 | Dilute about 1:1, or serve over a lot of ice |
| Ready to drink | 1:10 to 1:12 | Serve straight over ice |
| Ready to drink, light | 1:15 | A clean, tea-like cup |
How much coffee per batch
The grounds hold back about twice their dry weight in water, so you get less out than you put in, and less again the stronger you brew.
| Water | Concentrate at 1:5 | Ready to drink at 1:12 |
|---|---|---|
| 1 gal (4 L) | 1.7 lb (0.8 kg) → about 0.6 gal | 0.7 lb (0.3 kg) → about 0.8 gal |
| 5 gal (19 L) | 8.3 lb (3.8 kg) → about 3.0 gal | 3.5 lb (1.6 kg) → about 4.2 gal |
| 10 gal (38 L) | 16.7 lb (7.6 kg) → about 6.0 gal | 7.0 lb (3.2 kg) → about 8.3 gal |
| 20 gal (76 L) | 33.4 lb (15.1 kg) → about 12.0 gal | 13.9 lb (6.3 kg) → about 16.7 gal |
The recipe
The card scales from 1 to 30 gallons of water.
Bräu Supply recipe · Cold brew
Cold Brew Concentrate
Ingredients · for 5 gal of water
| 5 gal (18.9 L) | Cold filtered water | |
| 8.35 lb (3.79 kg) | Coffee, coarse ground | 1:5 by weight |
Process
- Grind: coarse, like raw sugar; fines cloud the brew and clog filters
- Load: coffee into a basket lined with a 400 micron nylon bag, then add the water slowly and stir until every ground is wet
- Recirculate: gently through the coffee bed for the first 10–15 minutes, until it runs clearer
- Steep: 12–18 hours at room temperature, or 18–24 hours cold
- Drain: lift the basket and let it drip; don’t squeeze the bag
- Filter: through a fine cartridge filter on the way to the keg for a clear, stable brew
- Keep: at 41°F (5°C) or colder, and use it within about a week
Make it in
The grounds hold back about twice their dry weight in water, so 5 gallons of water at 1:5 gives about 3.0 gallons of concentrate. Dilute it 1:1 with water or milk to serve, or 1:2 for a lighter cup.
Steep time and temperature
- Room temperature (68–72°F): 12 to 18 hours. The usual café method.
- In the fridge: 18 to 24 hours. Slower to extract, a little softer.
- Too long: past about 24 hours it turns woody and bitter without getting much stronger.
- Hot bloom: some brewers wet the coffee with a little hot water first, then add the cold water. It speeds extraction and brings out more aroma.
Grind and filtering
Grind coarse, like raw sugar. Fine grounds extract fast and bitter, and they clog every filter downstream. The cleanest commercial systems filter in stages: the coffee bed itself first, by recirculating the brew through it, then a 400 micron mesh, then a cartridge filter of 25 microns or finer on the way to the keg.
Food safety
Cold brew is a low-acid drink, around pH 5.4 to 5.6, and it is never heated. Keep it at 41°F (5°C) or colder from the moment it is filtered, use it within about a week, and clean everything that touches it every batch. Sealed cans and bottles that sit on a shelf need a validated heat or pressure treatment; talk to a process authority before you package it.
Frequently asked questions
What is the best ratio for cold brew?
1:5 by weight for concentrate you dilute 1:1, or 1:12 for cold brew you drink straight. Start there and adjust by taste.
How long does cold brew concentrate last?
Kept at 41°F or colder, about a week for best flavour and safety. It goes flat and stale well before it looks off.
Can I use regular ground coffee?
You can, but it brews muddy and bitter and is hard to filter. Ask for a coarse, French-press grind.
Is cold brew stronger than hot coffee?
Concentrate is much stronger, which is why it is diluted. The finished strength depends on the dilution: 1:1 is bold, 1:2 or 1:3 is closer to an everyday cup.
Making it at scale
Past a few gallons, buckets and paper filters turn into lifting, wringing and waiting. A Unibräu steeps the coffee in a lift-out basket, recirculates the brew through the coffee bed with its pump, drains through a tri-clamp valve, and heats for hot blooms, hot-brewed iced coffee and cleaning. See the cold brew system, or read how to make nitro cold brew.