You’re Grinding Your Coffee Too Finely—Science Says So

Most coffee aficionados will tell you that grinding your own beans is the secret to making a perfect drink at home. It's true that grinding the coffee right before brewing it makes for a fresher, better-tasting beverage, but not all freshly ground coffee is alike. If you grind your beans too finely, you may not be getting the most out of the product, as one study reports.

According to NewScientist, researcher Jamie Foster at the University of Portsmouth, UK, and his colleagues created a mathematical model to determine the most efficient way to brew espresso. Their findings were published in the journal Matter in March 2020.

The model simulated how ground coffee and water interact in the cylindrical basket of an espresso machine. When coffee brews, the ground-up beans infuse the hot water with flavor compounds. Coffee shops often grind beans on the finer side, assuming that the increased surface area of the grounds will yield a stronger drink. The researchers' calculations showed that this isn't necessarily the case.

When coffee grounds are coarse, water can flow freely around the basket. More of the individual grains are able to infuse the water with their compounds this way. Super-fine coffee is more likely to clump together and clog the cylinder, making for a less efficient brew. By going easy with your grinder in the morning, you're able to stretch your beans for all they're worth.

When an Oregon coffee shop reworked their recipe based on the study’s results, they saved $0.13 per cup, or $3620 in a year. But you don't have to be a professional barista to apply the findings to your own coffee habits. Just resist grinding your beans too finely before brewing your next cup. If you invest in a quality grinder, you’ll have greater control over your grind size. Here are more tips for brewing professional-quality coffee at home.

[h/t NewScientist]