What determines whether an espresso tastes delicious, thin or bitter? Science finally has the answer.
It is not known how much espresso the mathematician William Lee drinks a day. But the brew obviously appealed to the University of Huddersfield researcher. With the statistician Ann Smith, the scientist has repeatedly analyzed how coffee can be brewed in the best possible way. And now the two are targeting what appears to be a decisive factor: the so-called extraction, i.e. the extraction of the soluble ingredients from the ground coffee beans. It takes place when pressurized water flows through the bed of coffee powder. As Lee and Smith now, together with young researcher Arsalaan Arshad im journal physics of fluids report, this extraction is often uneven. And so – probably a nightmare for mathematicians – the result becomes difficult to calculate.