Cold brew is everywhere these days, from the fanciest third-wave coffee shop in the Mission to the Starbucks inside your grocery store. But according to a few Bay Area roasters, the trendy method--where grounds are steeped in cold water overnight--isn’t the best way to make iced coffee. Instead, places like Four Barrel, Highwire and Counter Culture advocate flash brewing, an improved version of the old-fashioned technique of pouring hot coffee over ice.
“My business partners and I...always preferred the brighter notes and balance in the cup that blooming coffee with hot water provides,” Robert Myers, owner of Highwire Coffee Roasters, wrote in an email. “[Cold brew made in a] Toddy, to me, always tasted muddled and thick. Smooth in an unpleasant way. An incomplete cup.”
Cold brew, which has been made in Japan since the 1600s, started its life in the US in high-end third-wave coffee shops. A flurry of trend articles followed, with places like the New York Times offering explainers and recipes to make it at home. As it’s popularity grew (marketing analytics firm Mintel reported that the cold brew category grew 580% from 2011-16) national chains like Starbucks and Dunkin’ Donuts added it to their menus. Consumers liked it because of its low acidity, and smooth, consistent flavor--a far cry from the traditional bitter iced coffees, made by simply dropping some ice cubes into a cup of old coffee. Plus, there’s the convenience factor. Portland’s Stumptown started producing their “Stubby” bottles of cold brew in 2011, and the market for cute, single-serving bottles of cold brew quickly expanded.
San Francisco’s Four Barrel Coffee made cold brew coffee for years, but always had problems with it. When cold brew steeps overnight, either on the counter or at room temperature, it’s exposed to oxygen, which can alter its flavor. “It has sort of this cloying oxidation flavor, which can be pleasant for the first few hours--it can taste like vanilla--but quickly starts turning into a fishy flavor,” said Four Barrel owner Jeremy Tooker.
Still, they continued to make it, in part because it was a great way to use up coffee that they had over-ordered. A few years ago, they tightened up their ordering. Since they didn’t need cold brew to use up their excess coffee, they decided to switch to a new method, where they prepared a slightly more concentrated cup of coffee and diluted it over ice. Coffee starts to lose its smell and taste the longer it stays at a high temperature, and the super-acidic, metallic notes that people don’t like come when coffee changes as it's left out. Cold brew eliminates that problem because it’s never hot, but you can also avoid it by quickly cooling it. So when Four Barrel’s baristas immediately lower the coffee’s temperature by putting it over ice, they were able to preserve the delicate notes in their coffees. They stuck with the method for a few years. About six months ago, they developed a way to replicate it on a mass scale. They created a patented, proprietary machine which cools their coffee down quickly--from 200 degrees to just above freezing in three seconds--and doesn’t require dilution or expose the coffee to air. The coffee then goes in kegs, and that cold coffee is now served in their cafes (they’re planning on bottling it in a few months.)
There’s nothing wrong with cold brew if that’s the taste you prefer, says Counter Culture Coffee’s Jesse Bladyka. He recommends flash brewing because he considers it a better way to express the complex flavors of their coffees. Certain smell and flavor compounds that make up the drinking experience can only be released when they’re exposed to hot water. “I think cold brew really limits the bandwidth,” he said. “And if you like the taste of cold brew, great. That’s awesome. But you can’t use cold brew to extract some of these pretty, floral citrusy things because it doesn’t work.” If you’re spending money on quality beans, with tasting notes of cherry or toasted marshmallow, why would you want to get rid of those subtleties by making cold brew, which can only extract certain flavors? Tooker agrees. “It has a homogenizing flavor,” he said. “You can use any coffee and they pretty much taste the same.”
So what should you do if you want to try flash brewed iced coffee at home? (Another bonus of the method: you get a cup of iced coffee immediately, without cold brew’s long steeping time.) The goal is to make a more concentrated cup of coffee, so it won’t dilute too much when you put it over ice. Use the same amount of coffee you’d usually use for a single cup, but grind it a little finer, and pour the water a little more slowly, recommends Tooker. Or try brewing with less water, suggests Myers. “At home, I make flash coffee by using about half the water I use to make hot coffee and dripping the coffee over a similar amount of ice,” he wrote. If you want to follow a recipe, Counter Culture offers a charming how-to video on their website. Experiment until you find what you prefer, urges Bladyka.