“Why do cold-brewed tea and coffee taste different than regular [hot] brewed? And what’s a good cold-brewing method for each?”
During any brewing process, as water penetrates tea or coffee, it releases lots of volatile chemical compounds, including caffeine and polyphenols, a type of antioxidant. “If the water is hot, it extracts more rapidly and completely,” wrote food scientist Harold McGee in The New York Times (7/20/11). “Hot water also cooks as it extracts, forcing chemical reactions that transform some of the extracted substances into other things, and driving some aroma substances out of the liquid. Cold water, in contrast, extracts more slowly and selectively, produces a simple extract, and doesn’t change the original flavor substances as much.”
McGee went on to explain that because cold-brewed teas and coffees are chemically different than hot brews—they typically contain less caffeine and acid—they don’t taste the same. “If you think of hot and cold brews as different drinks, just as a lager isn’t the same as a pale ale, then you may find you enjoy both,” he wrote.
That was a light-bulb moment for me. I’d always found that cold-brewed tea never measured up to the iced tea my Southern taste buds were used to—made by pouring boiling water over Luzianne or Lipton’s orange pekoe teabags and sweetened with a drizzle of simple syrup, a summer staple in my fridge to this day. (The syrup really is simple: Just combine 1 cup granulated sugar and 1 cup water in a saucepan. Bring to a boil, stirring, until sugar is dissolved. Let cool and keep in the fridge for cocktails and tea.)
The notion that it was time to broaden my horizons was given momentum by some teas I got from In Pursuit of Tea, the online emporium of tea merchant Sebastian Beckworth. (His tips for buying and brewing green tea appear in a previous column.) A Japanese sencha, which I’d cold-brewed overnight, was a revelation: Conjuring a cool, mossy stream, it was one of the most refreshing things I’d ever tasted. A cold-brewed oolong, from Taiwan, was floral and complex. Even cold-brewed tea made with Twinings loose English Breakfast was cleaner-tasting and less astringent than a batch of sun tea (in terms of food safety, it’s smarter, too).
Making cold-brewed tea is uncomplicated and easy—just what we all crave come August. Before brewing, I like to give the tealeaves a quick rinse under cold running water to rid them of any tea dust or impurities. Then put the tea in a clean pitcher or Mason jar, add cold water (use about one tablespoon tea for every quart of water), and refrigerate for about four hours or so before filtering. If the result is too strong, add water; if it’s too weak, add more leaves and let it infuse a bit longer. In general, you can do multiple infusions of the leaves for subsequent batches, and the flavor will evolve accordingly.
Serious coffee drinkers are an excitable bunch (all that caffeine!), so it’s no surprise that cold-brewed coffee has become a cult favorite. You do need to plan ahead: It can take 12 to 24 hours of steeping coffee in room-temperature water to make a concentrate that you first filter, then dilute with water (hot or cold) to taste. The result is smooth and intense, with low acidity and none of the bitterness or flat, murky taste you’ll find in hot coffee that’s been chilled or allowed to sit until cool. Because it’s a concentrate, you may find yourself using it as an ingredient in ice cream, milk shakes or smoothies, a chocolate cake, even barbecue sauce.
It’s easy enough to improvise a cold-brewing device with a French press pot or just a pitcher and a fine-mesh sieve, fine-mesh cheesecloth, and/or paper filters to strain out every last particle of ground coffee. McGee suggests infusing half a pound of coffee in about five cups of water overnight; he uses a coarse grind, but Dan Sousa at America’s Test Kitchen prefers a fine grind.
If you’re not the sort who enjoys fiddling around with filters and other accouterments, then think about ponying up $35 or so for a specialized cold-brew system like the Toddy, available at Amazon and William-Sonoma. I don’t even drink coffee, and I want one.
Given the passion that coffee inspires, cold brewing is not without controversy. Many coffee purists, for instance, will tell you that coffee needs hot water (between 195° and 205° F) to release the aromatics in ground beans. That’s why their version of a cold brew begins with a double-strength hot pour-over, utilizing a wood-collared Chemex (which drips directly onto ice cubes), or a French-press brew, which is then added to ice right away. The melted ice dilutes the coffee to drinking strength.
This hot-brew-over-ice method is very handy because you don’t need to plan ahead, but on the other hand, having a ready supply of coffee concentrate in the fridge (it keeps its freshness for weeks) is another sort of convenience. In both cases, throw out the used coffee grounds after using.
One last note: No matter whether you are interested in cold-brew tea, cold-brew coffee, or are an equal opportunity drinker, it pays to buy the best quality tealeaves or coffee you can afford.