How to Make Cold Brew Coffee

What Is Cold Brew Coffee?

Cold brew coffee is just what it sounds like: It's coffee that's brewed using cold water rather than hot water. Most popular home-brewing methods use hot water, including pour-over, drip, espresso and traditional French press coffee. Because it's made with cold water, cold brew takes much longer to make than other coffee methods. "It is made in a few different ways. The most popular is by steeping coffee, typically a coarser ground, in water for an extended period of time—18 to 24 hours—then straining in order to trap any loose grounds, and serving over ice," says Kappler. "The slow steeping process makes it different from other more traditional brewing methods that involve moving boiling water through coffee grounds."

What's the Difference Between Cold Brew and Iced Coffee?

While cold brew is cold from start to finish, traditional iced coffee starts with hot-brewed coffee that's cooled and then served over ice. Any sort of brewed coffee, including drip, pour-over and espresso, can be the starting point of iced coffee.

Why Should You Make Cold Brew Coffee?

Cold brew is popular for its super-smooth, round flavor—it often tastes sweet even without added sugar. Some people also find that it's easier on their stomachs because it tends to be less acidic than traditionally brewed coffee. "I like that cold brew is simple and easy to make, no matter what level of coffee connoisseur or drinker you are," says Kappler.

She adds that, while Roasting Plant has special equipment called a FlashChiller for making iced coffee, making traditional iced coffee without special equipment can yield oxidized, bitter or diluted-tasting coffee. That makes cold brew "an effective preparation method for the coffee drinker [who wants a cold cup of coffee and] doesn't have lots of coffee machinery or equipment at home."

Kappler also likes the fact that cold brew can be made ahead in big batches, which makes it great for entertaining.

How Much Caffeine Is in Cold Brew?

While how much caffeine is in a particular cup of cold brew will vary based on the specific beans, roast, ratio of ground coffee to water and brew time, cold brew does typically have more caffeine than traditionally brewed coffee, despite its deceptively smooth taste. "The longer steep time combined with larger coffee dose results in more caffeine in cold brew," says Kappler.

What Equipment Do You Need for Making Cold Brew?

To make cold brew, you'll need a container to brew it in—a large glass jar, such as a mason jar, works well. You'll also need something to strain the coffee with, such as cheesecloth, a flour sack, a thin dish towel, metal coffee filter, paper coffee filter or fine-mesh sieve. Kappler says that the finer the strainer, the smoother your coffee will be. You can also make cold brew in a French press, which serves as both a container and the filter.

What Is the Correct Cold Brew Coffee-to-Water Ratio?

Kappler's preferred ratio for cold brew is one part coffee to eight parts water, measured by weight. Kappler says it's worth it to use a kitchen scale to get the best coffee ratio, as a scale will give you the most accurate measurement. It also allows you to measure the beans before grinding. That said, in case you don't have a scale, we've included cup measurements in the recipe below.

How Long Does Cold Brew Last?

After you've filtered your cold brew, store it in a tightly sealed container in the fridge. While Kappler advises storing cold brew for no more than 24 hours for the best flavor, other experts say you can keep it anywhere from 3 days to 2 weeks. Let your own taste buds guide you.

How to Serve Cold Brew Coffee

"Cold brew is of course served best over a big glass of ice," says Kappler. "I don't like to add much other than that, but you can of course add your favorite milk or flavoring." If you prefer a more diluted drink, feel free to add water to your cold brew. Or take Kappler's recommendation and add half-and-half or a thick oat milk, such as a barista blend.

While some people like to heat their cold brew, Kappler isn't a fan of this approach—she says you're better off making yourself something like pour-over if you want hot coffee, since rewarmed cold brew "will taste like a hybrid between instant coffee and a hot brewed coffee."

Cold Brew Coffee Tips

Buy Freshly Roasted Beans

"The closer to freshly roasted the coffee is, the smoother the cold brew will be, with no bitterness," says Kappler. "If you want to know when your coffee shop's beans were roasted, just ask!" She recommends buying beans that were roasted no more than 10 days before you buy them.

Grind Your Beans Fresh

Like with other coffee brewing methods, cold brew tastes best if you grind the beans fresh. Grinding your own beans also gives you control over the coarseness of the grind. "A coarse ground is preferred for making cold brew, especially if using a French press," says Kappler. "The best way to achieve this is with a burr grinder like a Baratza or a Timemore hand grinder that allows you to fully customize the grind."

Seal It Tightly

When brewing cold brew, keep the container tightly sealed to keep as much air away from the coffee as possible. Kappler also likes to put a piece of plastic film right on the surface of the coffee-water blend to help prevent oxidation. Sealing the container tightly will also help to keep your cold brew from picking up fridge odors.

Keep It Cool

While some cold brew recipes suggest brewing the coffee at room temperature, Kappler says to keep it in the fridge. "The secret lies in the temperature," she explains. "You want to have the cold brew steeping in the fridge to prevent the oils and fats in coffee from oxidizing, so if you optimize for this by keeping the temperature low, then the cleaner, fresher and richer the result will be."