How to Make Cold Brew Coffee at Home: Ratio, Steep Time, Storage

You do not need a special brewer. A large jar, a fridge, a scale and a filter will do. Below you will find the gear list, a ratio table, a step-by-step recipe, and fixes for the most common problems.

The recipe follows the method published by Counter Culture Coffee, with storage and acidity details from other sources listed at the end. If you are new to measuring coffee by weight, our beginner home brewing lesson covers the basics.

What do you need to make cold brew at home?

You need coarsely ground coffee, cold filtered water, a container with room to stir, a fridge, and a way to strain out the grounds. A kitchen scale makes the results repeatable. A burr grinder helps, but coffee ground coarse at the roaster or store also works.

• Coffee: whole beans you grind yourself, or a bag ground coarse for cold brew or French press
• A scale that reads in grams
• A sealable container, such as a large mason jar, a pitcher or a French press
• A filter: paper coffee filters, cheesecloth, a fine mesh strainer, or a cold brew system with its own filter
• A second clean container to hold the finished concentrate

Counter Culture recommends sanitizing jars, brewers and filters before you start, because the long, unheated steep gives bacteria more of a chance than a hot brew does. Hot soapy water and a good rinse are a sensible minimum.

What is the best cold brew ratio?

A good starting ratio for cold brew is 1:8 by weight, or about 125 grams of coffee to 1,000 grams (1 liter) of water. That makes a concentrate you dilute before drinking. For a ready-to-drink brew with no dilution, use about 1:11. For a very strong concentrate, go as far as 1:4.5.

All three ratios come from Counter Culture's cold brew guide. Ratios are by weight, so 1,000 grams of water is the same as 1 liter. If you only have measuring cups, weigh your coffee once with a borrowed scale and note how many scoops it takes.

Ratios from Counter Culture Coffee's cold brew guide. Grams per liter are rounded.

How do you make cold brew, step by step?

Weigh the coffee and water, grind coarse, stir them together so every ground is wet, cover, and steep in the fridge for about 14 hours. Strain through a filter, store the concentrate in a clean, sealed container, and dilute each glass to taste.

1. Weigh 125 grams of whole beans for every liter of water you plan to use.
2. Grind the beans medium-coarse, a little coarser than you would for pour-over.
3. Add the grounds to your clean container, then pour in 1,000 grams of cold filtered water.
4. Stir while you pour so there are no dry pockets. Dry clumps waste coffee and brew unevenly.
5. Cover the container and put it in the fridge for about 14 hours. Overnight plus a morning works well.
6. Strain. Pour through a paper filter for a cleaner cup, or through cheesecloth or a mesh filter for more body. Expect some liquid to stay in the grounds.
7. Store the concentrate in a sealed container in the fridge and dilute each glass when you serve it.

Counter Culture notes that paper filters give a clearer, fresher-tasting cup, while cloth and fiber filters let more body through. If your brew is cloudy, run it through a paper filter a second time.

How long should you steep cold brew?

Start with about 14 hours in the fridge, which is Counter Culture's suggested steep time for its 1:8 recipe. Other roaster guides use 12 hours or more. Taste after your first batch: if it is weak or sour, steep longer next time; if it is harsh or woody, shorten the steep or grind coarser.

Cold water extracts slowly, so steep time does most of the work that heat does in a hot brew. Keep your ratio and grind the same while you test different steep times, so you know which change made the difference.

Steeping in the fridge from start to finish keeps the brew cold the whole time, which is the approach Counter Culture recommends. It is also the simplest way to keep food safety on your side.

What grind size is best for cold brew?

Use a medium-coarse to coarse grind, about the texture of raw sugar. Coarse grounds are easy to strain and resist over-extraction during a long steep. Counter Culture suggests going slightly finer than many cold brew guides do, which it says helps reduce sourness.

Grind that is too fine clogs filters, leaves sludge in the jar and can make the brew taste bitter. Grind that is too coarse can leave the brew thin. If you use pre-ground coffee, look for bags labeled for cold brew or French press, such as the Hula Daddy Kona Cold Brew, which the roaster sells coarse ground for this method.

How do you dilute cold brew concentrate?

Dilute a 1:8 concentrate with water or milk before drinking. Counter Culture suggests 2 parts concentrate to 1 part water for a strong cup, or equal parts for a milder one. Add ice after mixing. Dilute only what you are about to drink, and keep the rest as concentrate in the fridge.

Milk, oat milk and other dairy alternatives work the same way. Because they add body, many people use less concentrate in a latte than in a glass of black cold brew. Start with equal parts, taste, and adjust from there.

You can also mix concentrate with hot water for a quick hot cup on busy mornings.

How long does homemade cold brew last?

Homemade cold brew keeps for about a week in a sealed container in the fridge. A coffee educator at Partners Coffee recommends drinking it within one week of brewing, and Breville gives 5 to 7 days, with the best flavor in the first day or two. Once you add milk, drink it within 2 to 3 days.

Store concentrate on its own, without water or milk, and mix each glass when you pour it. Breville notes that pre-mixed cold brew breaks down faster. If a batch smells sour or off, or shows anything growing on the surface, throw it out.

Cold brew is brewed without heat, which is why the National Coffee Association published a safety guide on brewing and storing it for cafes and retailers in 2022. At home, clean equipment, cold storage and a one-week limit cover the basics.

Is cold brew less acidic than hot coffee?

Cold brew is less acidic in taste, but only slightly different in pH. A 2018 study in Scientific Reports found cold and hot brews of the same light-roast coffees had similar pH, from 4.85 to 5.13. The hot brews had more titratable acid and higher antioxidant activity.

Speaking about the study, the authors cautioned that cold brew should not be seen as a "silver bullet" for avoiding stomach upset. If you have reflux or another digestive condition, talk to your doctor about coffee in general rather than relying on the brew method.

A later study by the same Thomas Jefferson University group, presented in 2020, found hot and cold brews had about the same pH at each roast level, and both became less acidic as the roast got darker.

Why does my cold brew taste weak, sour or bitter?

Weak cold brew usually needs more coffee or a longer steep. Sour cold brew is under-extracted, so grind a little finer or steep longer. Bitter or woody cold brew is over-extracted, so grind coarser or shorten the steep. Muddy cold brew needs a finer filter or a coarser grind.

Change one thing at a time. If you change the grind and the steep time together, you will not know which fix worked.

Which coffee beans work best for cold brew?

Medium roasts with chocolate, caramel or nutty notes make the most forgiving cold brew. Dark roasts suit milk drinks, and fruity natural-process coffees work if you like a brighter glass. Any decaf you enjoy hot will make good cold brew too, with the same recipe.

A few coffees in our catalog fit well. The Coffee Bros. Cold Brew Coffee Blend is a medium roast of natural Brazil and Ethiopia that the roaster built for this method, with notes of dark chocolate, berry and brown sugar. Partners Coffee Brooklyn Blend is a medium roast the roaster describes as creamy cocoa, toffee and dried fruit. Brave Bean Coffee First Responder is a medium Brazil with chocolate, cherry and cranberry notes listed.

For evenings, Brave Bean Twilight Tonic Decaf is a medium Peruvian decaf with deep chocolate notes, according to the roaster. If you are curious how roast affects caffeine in your glass, our lesson on whether dark roast has more caffeine explains it.

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