This is a concept primarily used in the production of sparkling wines, such as Champagne. A perpetual reserve refers to a blend of wines from several vintages, which the producer preserves for an extended period. The goal is to maintain a certain consistency of quality and style in the final product, year after year. Each year, a portion of the harvest is used for the base wine (the young wines), but another portion is kept for future blends. Thus, older wines, which have been stored in reserve, are added to each new vintage, creating a "reserve" that lasts over time.