It may seem unusual at first, but if you want to make yourself a cup of coffee that’s a flavor experience, rather than a bitter means to a caffeine fix, you should try freezing your coffee beans. Johanna Klein of The New York Times swears by this method, saying that room temperature coffee beans are lacking in flavor by comparison.
But Why Frozen?
In a popular, bustling coffee shop, room temperatures can fluctuate throughout the day and coffee grinders are hotter the longer they are in use. Klein writes that this can be a problem, saying that “the consistency of the grind changes.”
Water that is brewed with the coffee extracts more from smaller coffee grounds than bigger ones. However, when the grind is inconsistent, the smaller coffee grounds can taste sour, and the bigger ones can taste bitter. To compensate for these varying tastes, baristas often adjust their grinder’s settings during the day.
The Science Behind the Freeze
In Bath, England, the Colonna & Small’s coffee shop wanted to experiment with coffee beans at different temperatures to combat these contrasting flavor profiles. They teamed up with local chemists at the University of Bath to observe the ways that temperature affected how coffee beans break. Their experiment began at room temperature, continually cooling the beans until their thermometers reached -321F, the same temperature as liquid nitrogen.
These scientists discovered that coffee beans produced more uniform particles when they got colder, and these particles accounted for an even flavor distribution.
“It’s important that all the particles in there are extracted at the same rate,” said Doctor Chris Hendon. “It’s kind of cute that you can do that just by cooling the beans down before you grind them.”
So, while it’s impossible for all of us to cool our beans hundreds of degrees below zero, Hendon points out that, while frozen temperatures can improve the flavor, there is one thing you need to brew a perfect cup of coffee without fail. “It doesn’t matter if you like it hot or cold, or how you grind it, as long as you do it the same way every time,” he said.