If a wine or Champagne is made from more than one vintage—that is, it's a blend of grapes grown in different years—it's called a non-vintage wine, since the majority isn't necessarily composed of a single vintage. You'll see this term a lot on bottles of Champagne, since about 80% to 90% of Champagnes are made from a blend of three or more wines of various vintages. NV wines are created to allow the winemaker to produce a consistent style of wine that loyal customers have come to rely on. In Champagne (the region), this is called the house style. Producers often blend one vintage with another wine out of an economic or marketing need as well. For example, if the winemaker had to rely on one season's grapes and it was a particularly lousy year for growing grapes, the quantity and quality of the Champagne would suffer. Many dessert winessuch as sherry are NV blends as well.