Acidity in Arabica coffees is almost always considered a positive flavor attribute, yet the term can sound unattractive. People may relate acidity to stomach discomfort, or to sour flavors. This would be incorrect. The acidity in good high-grown Arabica imbues the cup with delicate flavor accents, complexity, and dimension. Good acidity is fleetingly volatile, a momentary sensation, giving effervescence to the cup, and informing the mouth feel as well. Coffees with no acidity can taste flat. Acidity is not about quantity, it is about quality, and good coffees have a complex balance of many types of acidity: malic, citric, acetic, phosphoric, quinic, to name a few … and a whole set of chlorogenic acids that are very important to flavor experience as well. Kenya’s, which by flavor are some of the higher acid coffees, actually have measurably less than Brazil Arabica (of quinic and citric acids), more of others (malic, phosphoric) and far less than some Robusta coffees (chlorgenic acids)! Dark roasts tend to flatten out acidity in flavor. But contrary to the taste, darker roasts have more acidity than lighter roasts. So quantity does not always follow perception. Acidity in coffee might be described by terms like bright, clear, effervescent, snappy, dry, clean, winery, etc. Coffees without acidity tend to taste flat and dull, like flat soda. Acidity is to coffee what dryness is to wine, in a sense. Different coffee origins will possess different kinds of acidity; like the wine-like high notes of some African coffees versus the crisp clear notes of high grown coffees from the Americas. Unpleasant acidy flavors may register as sourness.