Cold Brew Concentrate

Cold brew concentrate is cold brew made deliberately strong, with about four or five times as much water as coffee instead of the eight or more you’d drink as it is. You keep it in the fridge and dilute each glass with water, milk or ice. It takes up less room, keeps for up to about two weeks, and lets you make anything from a long iced coffee to a hot mug. This page covers the concentrate itself: a recipe, how to dilute it, how long it keeps and the safety questions. For cold brew in general, see the main cold brew guide.

The short version

• About 1:4 to 1:5 coffee to water, coarse ground.
• Steep 12 to 24 hours, then strain well.
• Dilute about 1:1 with water or milk, more if you like.
• Keep it sealed in the fridge and use it within about two weeks.
• Not less acidic by pH than hot coffee, despite the reputation.

What makes it a concentrate?

Only the ratio. You brew with much more coffee, so what comes out is too strong to drink neat. America’s Test Kitchen says plainly that its concentrate “needs to be diluted before drinking”. Two published recipes show how strong that is:

Recipe	Coffee	Water	Ratio (about)	Steep
America’s Test Kitchen	8 oz (227 g), coarse	4 cups (946 ml)	1:4.2	24 hours, room temperature
Toddy	12 oz (340 g), coarse	7 cups (1.65 litres)	1:4.9	12 to 24 hours, room temperature

Toddy says its batch gives about 38 oz (about 1.1 litres) of concentrate. Coarse grounds soak up a lot of water, so you always get noticeably less out than you put in.

How do you make it at home?

This is America’s Test Kitchen’s recipe, which uses a jar, a strainer and a coffee filter:

1. Combine 8 oz (227 g) of coarsely ground medium-roast coffee with 4 cups (946 ml) of room-temperature filtered water in a 2-quart jar or narrow pitcher.
2. Stir the raft back in. After about 10 minutes the grounds float up into a raft; stir them back in.
3. Steep for 24 hours at room temperature, covered.
4. Strain once through a fine-mesh strainer, stirring gently to help it through.
5. Strain again through the strainer lined with a coffee filter. It can take up to 10 minutes.
6. Chill in an airtight container.

Brew mode on this page times the stir, the steep and the second strain for you. If you’d rather not strain by hand, a Toddy with its felt filter or a Hario cold brew bottle does the separating for you.

How do you dilute cold brew concentrate?

There’s no single rule, because concentrates vary in strength. Follow the maker’s ratio for a bought concentrate, and taste as you go with your own:

Source	Concentrate	Mixed with	Notes
Starbucks	1 part (6 oz)	1 part (6 oz) cold water	Over ice; use 1:1 for bigger batches too
America’s Test Kitchen	1 part (½ cup)	1 part (½ cup) cold water	Over ice, with an optional pinch of salt; dilute more if you like
Toddy	1 part	About 3 parts water or milk	Toddy’s own concentrate; for hot coffee, 1 part to 3 parts steaming water

A few tips:

• Ice dilutes too. Pour over plenty of ice and you’ll want a little less water.
• Milk instead of water makes an iced latte-style drink; Starbucks suggests stirring in milk, sugar or other flavours.
• Dilute by the glass, not the whole batch. Undiluted concentrate is the form that keeps.

How long does it keep?

Source	Storage advice
Starbucks	Refrigerate after opening and use within 14 days
Toddy	Up to 2 weeks in the fridge

Keep it in a clean, sealed container in the fridge, and throw it away if it smells or tastes off. Once diluted, drink it the same day.

Is cold brew concentrate safe?

For cold brew made and kept in the fridge, a Cornell University food safety blog post says there’s not a lot to be concerned about: the roasted beans are close to sterile, and cold storage holds bacteria back. Its concern is cold brew sealed without oxygen, such as nitrogen-infused cans. It says there’s no scientific information showing cold brew is safe in reduced-oxygen packaging, because coffee isn’t acidic enough to stop Clostridium botulinum, the bacterium behind botulism. Cornell’s expert notes the toxin can’t form at pH 4.6 or below, and cold brew sits at about 5.

What that means at home:

• Keep it in the fridge, not on the counter, once it’s strained.
• Don’t seal it airless or make your own nitro cans for long storage.
• Use it within the maker’s time, about two weeks.

Is it less acidic than hot coffee?

Not by pH. A 2018 study in Scientific Reports by Niny Rao and Megan Fuller brewed six light-roast coffees both hot and cold with the same ratio. The pH values were comparable, 4.85 to 5.13. The hot brews had more titratable acid and higher antioxidant activity, which the authors suggest comes from hot water extracting more acids. So cold brew can taste smoother, but it isn’t a low-acid drink in the pH sense.

Should you buy concentrate or make it?

Bought concentrate is convenient and comes with the maker’s dilution and storage instructions printed on it. Home concentrate costs less per glass and lets you pick the coffee, but you have to strain it well and keep track of its age. Either way, read the label or recipe for the ratio, because one brand’s 1:1 can be another’s 1:3.

General guidance only. Keep cold brew concentrate refrigerated, follow the maker’s storage times, and don’t store it in airless sealed containers.

Cold brew concentrate vs other methods

• Cold brew: the full guide to cold brew, at drinking and concentrate strengths.
• Toddy cold brew: the classic system for big batches of concentrate.
• Kyoto drip: slow cold drip, a different way to brew cold.
• Nitro cold brew: cold brew served with nitrogen.
• Liquid coffee concentrate: shelf-stable coffee extracts and essences.

Explore every cold method in the cold chapter.