For all its hype, cold brew coffee remains a mystery. The brewing method – which involves exposing ground coffee to water (room temperate to refrigerator cold) for up to 24 hours – is still mostly unexplored, as far as hard science is concerned, anyway (especially so when compared to its hot coffee counterpart). This means that, to this point, most information on subject is based on anecdotes and repeated half-truths. An example: "cold brew coffee is less acidic than regular coffee." Wrong. Cold brew coffee is a similar pH level to hot coffee – the acidic difference, so far as we know, is only perceived.
Another half-truth: cold brew coffee tastes the same no matter what. We've reported on this one. This isn't exactly right. Here's what you need to know about what makes the best coffees for cold brewing.
The same coffee will taste different hot vs. cold.
Perhaps this bears repeating. Removing how water of different temperatures changes the brewing equation, the simple fact that you drink cold brew chilled and regular coffee hot plays a huge role. Elika Liftee, a trainer at Arkansas-based Onyx Coffee Lab, uses a hot bottle of Coke to explain. "Have you ever left Coke in your car, when it’s hot it tastes way too sweet and heavy, but can be refreshingly sweet when cold?" That's cold brew, Liftee says, which means even your favorite bag of beans may not stand out when served on ice.
For better cold brew coffee, go big or go home.
One of the beautiful things about coffee is its enormous complexity. Depending on how its grown, processed, roasted, ground and brewed, its flavor possibilities are nearly endless. According to Jackson Shuttleworth, co-founder of Jova Coffee, a soon-to-be-released cold brew coffee maker, the traditional cold brewing cycle has a knack for flattening certain flavors.
"Because people primarily drink immersion cold brew, and because those flavors can be muddled, you're not going to get super bright, sharp notes," Shuttleworth says.
Shuttleworth, who started prototyping the design with his business partner Olivia vonNieda in their last year at Harvard Business School, suggests this is where many cold brew drinkers develop the idea that cold brew is always "smooth."
Liftee's solution: go big or go home.
"If there are not any punchy standout flavors then the cold brew will taste muted, mild or boring," Liftee said. "More mild, or even more balanced coffees may not seem very flavorful in cold brew like something with one or two hard hitting flavor notes."