Espresso
also: shot, espresso shot
A small, intense coffee forced through fine grounds under about 9 bar of pressure.
Espresso is a brewing method, not a bean. Hot water at around 90 to 96 C (194 to 205 F) is forced through a compacted bed of finely ground coffee under roughly 9 bars of pressure, producing a small, concentrated shot in about 25 to 30 seconds. The pressure is what sets it apart from filter coffee: it emulsifies oils and dissolves CO2, giving espresso its syrupy body and its cap of crema.
Why it matters: espresso is the base for most cafe drinks, from a latte to an americano. Because so much is extracted from so little water, it tastes intense and is sensitive to small changes. A typical modern shot uses an 18 to 20 g dose yielding around 36 to 40 g of liquid, a brew ratio near 1:2.
It is concentrated rather than simply “strong” in caffeine: a single shot holds less total caffeine than a mug of drip, but far more per milliliter. Getting it right means controlling grind, dose, and yield together. See espresso-basics to start, and a double shot is a doppio.