Bianca Nogrady wrote:In the terrestrial coffee world, that build-up of static electricity makes ground coffee clump together in the basket, and "when you have these clumps that form, you inherently get variable espresso", says a computational materials chemist, Prof Christopher Hendon, from the University of Oregon in the US.

His study tried to vary a lot of things - the bean, the roast, the moisture content, the grind size - to see if that changed the static built up. They found the single-biggest factor was moisture: the drier the bean, the more static you get. A simple spray of water on to the beans before grinding would solve the clumping problem.

And here's where the die-hard coffee tragic might roll their eyes and point out that serious coffee-heads have been doing this for years. It even has a name - the Ross droplet technique.