Bitterness
苦味
TastingDefinition
Bitterness is a basic taste picked up by the tongue's TAS2R receptors, in coffee driven mainly by caffeine and by chlorogenic acid lactones formed during roasting. Cuppers treat it as welcome when it stays in balance — dark chocolate, roasted nuts — and as a fault when it turns harsh, ashy or clings to the throat.
Etymology
Old English bitter, from a Germanic root. Caffeine's bitterness is thought to have evolved as a warning signal against toxins, which humans then learned to enjoy.
In use
A note reading 'pleasant bitter finish, dark cocoa' signals balance; 'harsh and ashy' signals a roast or extraction problem.