A Guide to Cold Brew Coffee

Ten years ago, there weren't that many coffee shops that served cold brew. Now, you can find cold brew everywhere, from megachains like Starbucks to the aisles of supermarkets. 

But just because it's everywhere doesn't mean everyone knows what it is. To answer some of your most common cold brew questions, I talked to Brent Wolczynski, Head Brewer of Cold Brew Production for Stumptown Coffee Roasters. Stumptown started bottling cold brew in 2011, which was an incredibly novel idea at the time. But now, Stumptown’s cold brew stubbies, whose brown bottles are now an iconic symbol within the cold brew world, are one of the most popular ready-to-drink products and just one of a handful of Stumptown cold coffee drinks on the market.  

So, What Is Cold Brew?

Cold brew is simply coffee that has been brewed with cold rather than hot water and usually involves a long steeping process—anywhere between 12-24 hours. In terms of flavor, cold brew is generally characterized as smooth, low-acid, and heavier than its hot brewed counterparts. 

Although cold brew has been around for centuries, it’s really in the last ten years that it's become a staple on coffee shops menus and recognizable by most coffee drinkers—a 2019 study by the National Coffee Association shows that 80% of respondents under 40 know what cold brew is and that 20% drink cold brew occasionally. "That was not the case in 2010,' Wolczynski says. "Communicating the difference between iced coffee and cold brew was difficult, let alone trying to convince people that this thing called cold brew that comes in an amber stubby bottle isn't beer."

How Do You Make Cold Brew?

Cold brew is a great drink for folks who've never brewed coffee at home because precision isn't as important as with other brewing methods. You don't need a scale or a kettle or anything. All you need is a brewing vessel, coffee, water, and patience. 

If I had to write the simplest recipe for cold brew, it'd be this: grind coffee coarsely, add water, let sit, and strain. One of the unique things about cold brew is that you're not brewing it to make a final product, but rather a concentrate, which you can dilute to your desired tastes with things like water, milk, or ice, so you can be a little less particular about the exact amount of water and grounds you use. Of course, if you want an exact recipe, Daniel has one right here. If you're looking for a cold brew coffee maker, I've got suggestions for you for a number of different devices in my review of the best ones on the market right now.

What Kind Of Coffee Should I Use for Cold Brew?

Pick the best coffee you feel comfortable paying for. Cold brew tends to have a heavy, chocolate-y flavor to it with low acidity, so sometimes baristas tend to favor coffees that lean into those flavors, like ones from South and Central America. 

However, coffees with pronounced fruitiness can flourish in cold brew. "I think the acidity of lighter roasted coffee really shines in cold brew against the sweet profile that cold water extraction provides," says Wolczynski, noting that how you drink your coffee might affect what you chose to brew: a lighter roasted coffee does best when enjoyed without milk and a heavier coffee can stand up to milk and sugar. "It's really down to personal preference and how you take your coffee."  

Perhaps more critical than the coffee you choose is the water you use to brew. "Good water is huge. Coffee is ~98% water so it's super important that you think the water you’re brewing with tastes good.” A good rule of thumb is that if you'd drink from the tap, you're likely okay to brew with that water. If not, consider filtered water. 

Can I Make Cold Brew with a French Press? 

Yes! A French press is a perfect vessel for making cold brew since you can filter the grounds with the plunger.

One tip for brewing with a French press: your coffee might have a heavy mouthfeel and a gritty texture. After brewing, try running your cold brew through a paper filter to catch some of the fine grinds and oils contributing to that mouthfeel, but also feel free to skip this step if you want a brew with more heft. 

Does Cold Brew Have More Caffeine Than Hot Coffee? 

Usually yes, but that's a numbers game rather than a brewing one. There's nothing inherent to cold brew that makes it a more caffeinated drink than the amount of coffee used to brew it. 

Most hot coffee is brewed using 14-18 grams of water per gram of coffee. Cold brew is made using a tighter ratio—Wolczynski recommends starting with 12 ounces (340g) of coffee to 64 ounces (1814g) of water, which is a much higher ratio of coffee to water. (He then recommends cutting the brewed concentrate with one part concentrate to one part water, which makes the final drink less intense than the concentrate, but still slightly stronger than a cup of drip coffee.)

Brewing coffee is all about using water to extract flavor (and caffeine!) out of ground coffee, and there's no magical process that extracts more caffeine when brewing with cold water. On that note, please feel free to make your cold brew with decaf coffee! 

How Long Does Cold Brew Last?  

Cold brew will usually last 7-10 days in the fridge. If your coffee tastes funky, you might want to give it a toss. If you notice that your coffee seems to be spoiling quicker than it should, it might be time to clean your brewing equipment. Old coffee oils get stuck to surfaces and can make your cold brew go bad more quickly than coffee brewed with clean equipment. 

If there's one thing I’d want people to take away from this article—or from anything I’ve ever written about coffee—it's that experimentation is the key to finding the perfect cup of coffee. Luckily, cold brew is an easy method to tinker with. "I would encourage people to play around with a few of their favorite coffees and experiment with different filtration methods and dilution levels," Wolczynski says. "Some coffees really do great at a super high concentration and it's nice to have just four ounces of a super syrupy, heavy cold brew over ice. Other coffees taste great at a really low concentration and the added water opens up access to entirely new flavors. A fun exercise is to line up a few cups of the same batch, all diluted at different levels, and compare them all to see what you like best." 

Overall, there's no one way to make cold brew, and if you decide to give it a try, have fun and find freedom in the form. Cold brew should be unfussy and it's easy to get an amazing cup at home—as long as you're willing to wait.