Definition: The acidity in wine is really the pucker power of a wine, some would even say the "sour-factor." A wine's acidity is what makes your mouth water after sipping (in contrast to tannins that typically dry out your mouth after sipping). If a wine is overly sour it is labeled as "tart" if it has very little acidity it is called "flat." The acid in wines is derived from the grapes used to make the specific wine. Acidity allows wine to maintain its freshness while also molding its flavor components. A wine with well-balanced acidity is not only a joy to drink, but also makes for exceptional food-pairing versatility.