Doppio
Doppio espresso is a double shot, extracted using a double coffee filter in the portafilter. This results in 60 ml of drink, double the amount of a single shot espresso. More commonly called a standard double, it is a standard in judging the espresso quality in barista competitions but only because four single espresso are made using two double portafilters. Doppio is Italian multiplier, meaning "double"
A single shot of espresso, by contrast, is called a solo and developed because it was the maximum amount that could practically be extracted on lever espresso machines. Today the Doppio is the standard shot, and because solos require a different filter basket, solo shots are often produced by making a doppio in a two-spout portafilter, but only catching one of the streams.
