Acidity n. Term for the bright, dry taste notes in coffee - not to be confused with unpleasant sourness.
Like wine, coffee has its own set of jargon and terms that may mean one thing when you're not talking about the latest bean from Jamaica, but quite another when you are. In coffee, acidity has a very specific meaning, but some roasters and coffeeshops avoid using it for fear customers will think it designates sour or biting rather than as the technical term that it is.
Acidity in coffee is similar to the dry taste found in red wine. It's tasted on the side and back of the tongue. It's characterized by the high, thin notes, sometimes with faint fruity flavors. People sometimes call it tartness, snap, or twist. It's not actually a sour taste and shouldn't be confused with undesirable sourness.
Some coffees, especially those grown at high altitudes, have especially high acidity and are actually called acidy. These have high acidity and full body, and their taste is sharp, bright, and snappy - as opposed to sweeter, more mellow flavors. These are usually young coffees; older beans almost never have that kind of snap.
Coffees with high acidity also have an aftertaste that is best described as "winey," with a high fruity taste and notes that linger on the palate.
Arabica coffees usually have a distinctive high acidity, as do other coffees from Africa.
(Photo: White Rock Coffee Roasters)