Including a drop of water to your espresso beans earlier than grinding them can scale back mess and result in a extra flavourful brew.

Espresso aficionados usually add a little bit water to their beans earlier than grinding, both from a moist spoon or as a spritz of moisture, as a result of it stops espresso grounds sticking collectively and retains them from flying away from the principle pile. Scientists assume it’s because the water reduces static electrical energy, however the actual mechanism and the proper quantity of water so as to add have been unclear.

To analyze, Christopher Hendon on the College of Oregon and his colleagues sprayed numerous quantities of water on a variety of espresso beans that had been roasted for various lengths of time, with various ranges of inside moisture, after which put them by a grinder. They then measured the quantity of static electrical energy, how giant the bottom espresso particles have been and the flavour of the espresso brewed with an espresso machine.

They discovered that crucial think about figuring out the electrostatic cost, and so the clumpiness of the espresso, was the overall moisture within the beans earlier than grinding. Beans roasted to a darker color have much less moisture, and this makes them extra prone to clumping.

“It’s not in regards to the origin or the processing methodology. It’s not in regards to the high quality of the espresso or the worth that one may pay for these specific beans,” says Hendon. “It actually boils right down to the color of espresso and the interior moisture.”

Including round 20 microlitres of water per gram of espresso – or round half a millilitre for a typical brew – can cease the grounds clumping collectively and enhance the consistency and flavour of an espresso, says Hendon. “If you happen to squirt a little bit water on it, you’re gonna see a distinction in brewing,” he says.

In addition to serving to folks make higher espresso at house, the addition of water earlier than grinding might save a whole lot of hundreds of thousands of {dollars} for business espresso firms, says Hendon. It’s because the ensuing floor espresso is much less clumpy and so extra water can percolate by it, lowering the quantity of espresso beans you could make a brew of a sure power.

“This paper might make a small however vital change to the method of brewing espresso espresso,” says William Lee on the College of Huddersfield, UK. “Probably the most intriguing facet of the examine is the investigation of clumping of grains as a consequence of electrostatic charging. This might have an effect on the style of espresso, as water will be unable to penetrate these clumps.”