Why adding water when you grind coffee beans makes for a better brew

Adding a drop of water to your coffee beans earlier than grinding them can cut back mess and result in a extra flavourful brew.

Coffee aficionados usually add a little water to their beans earlier than grinding, both from a moist spoon or as a spritz of moisture, as a result of it stops coffee 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 had been unclear.

To examine, Christopher Hendon on the University of Oregon and his colleagues sprayed varied quantities of water on a vary of coffee beans that had been roasted for completely different lengths of time, with various ranges of inside moisture, after which put them via a grinder. They then measured the quantity of static electrical energy, how massive the bottom coffee particles had been and the flavour of the coffee brewed with an espresso machine.

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

“It’s not about the origin or the processing method. It’s not about the quality of the coffee or the price that one might pay for those particular beans,” says Hendon. “It really boils down to the colour of coffee and the internal moisture.”

Adding round 20 microlitres of water per gram of coffee – 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 squirt a little water on it, you’re gonna see a difference in brewing,” he says.

As effectively as serving to individuals make better coffee at residence, the addition of water earlier than grinding may save a whole bunch of tens of millions of {dollars} for business coffee firms, says Hendon. This is as a result of the ensuing floor coffee is much less clumpy and so extra water can percolate via it, decreasing the quantity of coffee beans you have to make a brew of a sure power.

“This paper could make a small but important change to the process of brewing espresso coffee,” says William Lee on the University of Huddersfield, UK. “The most intriguing aspect of the study is the investigation of clumping of grains due to electrostatic charging. This could affect the taste of coffee, as water will not be able to penetrate these clumps.”