Published May 1, 2010. From Cook's Illustrated.
Though the method has been around for centuries, cold-brew coffee has only recently gained the notice of caffeine cravers in the United States.
Though the method has been around for centuries—some believe it may have originated in ancient Peru—cold-brew coffee has only recently gained the notice of caffeine cravers in the United States. We reviewed two products that claim to make coffee with less acid and caffeine and no bitterness. They work by steeping coffee grounds in cold water over a prolonged period (12 to 72 hours, depending on desired strength) to release smooth-tasting compounds. The resulting extract is then diluted with hot water for serving.
After comparing cold-brew coffee with coffee from a traditional drip machine, we found both cold-brew machines did, in fact, deliver a less bitter, less acidic, smooth beverage. Lab tests revealed they also had less caffeine. The low-acid taste might not please all palates—the mildness was either received as a pleasant break from coffee's usual bitterness or frowned upon as "kiddy coffee" or "coffee on training wheels." However, a few tasters felt they could drink this milder brew without the milk and sugar they use to tame regular coffee.
The Hourglass Coffee Maker is a good choice for those who prefer a milder, smooth, less bitter coffee. Though the coffee extract takes considerably longer to brew than regular coffee (between 12 and 72 hours) and requires more ground coffee per ounce than traditional drip coffee makers, once made, it allows you to whip up a quality cup of coffee in minutes and can be conveniently refrigerated for up to two weeks.