How to Make Cold-Brew Coffee at Home, According to the Experts
Cold-brew coffee is the mind-sharpening, energizing boost you need for summer 2021.
The moment my local coffee shop reopened after the long uncertain season, I was there. It was strictly for takeaway, and that was a bit of a bummer, because Rough Draft is a bookstore and bar, too (in an 18th-century stone house, no less), and lingering over a pint while thumbing through a hardcover is their entire M.O. But I was there out of solidarity — I wanted them to make it through — and because I missed the community vibe. I also sorely missed the coffee. On my first day back, co-owner Anthony Stromoski gave me a virtual high-five and served me a cold brew with a depth-charge shot of espresso. It fired every synapse in my brain, and made we wonder: Can I make cold brew coffee like this at home? After asking the Stromoskis, as well as the experts at Trade Coffee and Irving Farm, for their hard-won secrets, I can confirm that the answer is a hard yes. And it doesn’t require any crazy equipment. Here’s how to make the best cold-brew coffee at home.
So, What Is Cold-Brew Coffee?
Let’s get this sorted first: cold brew is not iced coffee, which is simply hot coffee cooled and diluted with ice cubes. Rather, it’s a coffee concentrate that comes from steeping grounds in cold water. Since no heat is is involved in the process, cold brew is smoother and, contrary to popular belief, much less acidic.
Cold brew is a lot like iced tea. It steeps at least overnight (12 to 16 hours is ideal) at room temperature, and keeps for several days after that in the fridge. Amanda Stromoski, who runs Rough Draft with Anthony, says they experimented with cold brew like chemists when they first began, until they got the formula just right. Now, it’s the core of their business each summer.
There’s a good reasons for this. “Cold brew is the least sensitive form of extraction,” says Nick Berry, Irving Farm’s in-house coffee professor. The very slow process — soaking ground coffee in water for hours — makes it almost flub-proof.
You can think of coffee types as existing on a spectrum of fussiness, Berry explains. At one end is espresso, which is very sensitive to process. The grind, the steam pressure, the temperature, and the timing have to be precise. It’s easy to screw up. Next is drip, where the coffee is exposed a little longer and gravity is pulling the nearly boiling water through, followed by French press, where coffee sits in a hot water basin for a few minutes, steeping. Then, we get to cold brew, where the water is, yes, cold and the exposure is long: The process is as gentle as possible.
“It’s sort of like smoking meat,” Berry explains. “Slow and low are key.”
How to Choose Your Roast
So what kind of coffee beans make for the best cold brew? Trade’s Director of Coffee, Maciej Kasperowicz, suggests using Trade’s online shop to search for iced coffee or cold brew. The options you’ll get will be for medium-to-dark roasts — nothing as burnt as so-called French roast or “Full City” roast. Why? Well, for cold brew, he explains,“You’re aiming for some of the brown sugar flavor notes from medium roasts, because those stand up to cold brewing.” A lighter roast or a fruitier profile isn’t bad, he says, but “you just risk losing those flavors, because they’re not going to show up.”
Perspectives vary. And Berry says not to sweat too hard about which coffee to use, as long as it’s at least a medium roast. He compares an average cold brew to drugstore chocolate: it’s still chocolate.
How to Grind Your Beans for Cold Brew
Trade lets you select a cold brew grind for the coffee you buy; Irving’s selector will default that to percolator. But what you’re looking for, Berry says, is coffee grounds the consistency of coarse sea salt, which is a bit coarser than you’d use for French press. There isn’t a massive difference between French press and cold brew grind, Kasperowicz explains, but if your mixture is too fine “you’ll get silt or grit in your glass of iced coffee.”
A general note about grinding beans: beware the blade grinder, which is the best way to trash an expensive bag of beans. Unlike a more expensive burr grinder, which draws beans consistently through a set of gears, a blade grinder rattles the beans around, and the result is frequently an inconsistent mix of powdery and coarser coffee. That means that you can’t consistently extract from the mixture. As Kasperowicz puts it, you’re basically “leaving rocks at the bottom of the ocean,” meaning much of the coffee isn’t being absorbed, leading to weaker flavor.
If you’re getting serious about grinding coffee at home, you should really invest in a burr grinder. But if you don’t want to shell out for one, just ask your local barista grind your beans on their burr grinder. (Yes, that means buying their beans, or at least a macchiato, and then tipping extra well.)
How to Measure Grounds for Cold-Brew Coffee
The next step is to be sure you’ve got the right ratio of coffee to water. Also, you want to do this operation in a big glass jar. If you’re bothering to make cold brew you’re probably not just going to want a single mug, and Amanda Stromoski says as long as you keep it cold after extraction, you can make a few days’ worth of cold brew at time. Kasperowicz’s target is an 8-to-1 ratio of water to ground coffee by weight, but he also thinks you should experiment.
“Just know it’s easier to add more water to dilute a concentrated coffee but there’s not much you can do about coffee that’s too watery,” he says. Don’t have a scale? The easiest way to get roughly the same result, I found, is a half cup of coarse grounds to 16 ounces of water.
How to Cold-Brew
There are a few ways to make cold brew. The cheapest method is to just put your ground coffee in the bottom of the jar and add your measured cold water. Then stir to make sure your coffee is well saturated and cover the jar, leaving it to sit at room temperature overnight. You can also use a Toddy system. This is essentially like a drip coffee maker for cold brew. Rough Draft uses a pro model, but Toddy makes two sizes for home use. A larger and smaller model.
Irving’s Nick Berry says a perfectly fine “hack” is to just buy Toddy’s coffee bag filters (think of them as giant tea bags you fill with coffee) and use them in any jar. In that method you’d add your ground coffee to the bag and steep in your measured water in the jar. If you use the Toddy method the coffee goes in the bag, and the bag sits in the water as well.
Whether using Toddy’s method or your own hack, using their bags, you extract the bag and let the remaining coffee drain back into the jar or their carafe. If you just mixed together loose grind and water, you’ll need to strain the ground coffee the next day, pouring the liquid through a fine mesh sieve lined with cheesecloth, and be sure not to let any of the saturated grinds spill through. This is achievable, but we’re here to advise you that it’s messy, hardly foolproof, and buying the Toddy bags is by far the easiest, least annoying method we’ve tried.
If you’re really into shortcuts, you can purchase Trade’s cold brew bags, which, though they’ll cost you more than buying coffee in bulk, are definitely goof-proof.
How to Supercharge Your Cold Brew
If you like your coffee a little sweeter you’re going to be disappointed adding granular sugar to a cold mug; the sugar will just sink to the bottom. Instead, make simple syrup is dead easy. Just dissolve sugar in water in a warm saucepan, SLOWLY bring to just under a boil while you stir. When you have a totally clear fluid with the sugar melted into the water you’re good. Let cool. Simple syrup is fine in the fridge for about a month, so bottle what you’ve made to have it at the ready.
If you have an espresso maker the best way to supercharge a cold-brew is to brew a single shot, pour over a few cubes, then add your cold-brewed coffee and more ice. (Note: Pulling the espresso shot directly over the ice melts the latter too quickly.) Trade’s Kasperowicz says you can experiment with a cocktail shaker, filling it with ice, pouring in the cold brew, shaking hard, then straining out the coffee. He likes this method, just because the coffee doesn’t get as watery on a hot day, the way it would when poured directly over ice.
If you’re a traditionalist, who always likes hot coffee in the morning, we like Amanda Stromoski’s tip — the workout-motivator method, to gulp in the afternoon. “Just take a short glass, pour your cold brew over a couple big ice cubes. Sweeten and milk to taste. You’ll get a quick caffeine punch to fuel your after-shift run.”
So, there you have it. Cold brew is, honestly, pretty effortless and inexpensive. All you really need are water, coffee grounds, and time.
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