The calvados of the Pays d'Auge has been granted an Appellation d'Origine Controlee by the French government, guaranteeing its authenticity. Appellation regulations for the region require that calvados du Pays d'Auge be double-distilled in the traditional manner, aged in oaken casks, and not be sold until it is at least two years old. (Calvados labeled as "Vieux" or "Reserve" has been aged for at least three years. The terms "VO," "VSOP," or "Vieille Reserve" promise spirits at least four years of age, and calvados more than six years old may be called "Hors d'Âge," "Napoleon," "Âge Inconnu," or "Extra." In blended calvados, the age of the youngest brandy applies.) Because calvados, like all dry spirits, improves only in the cask, it is not bottled until it is required for sale. Throughout the aging process, distilled water is introduced into the casks to reduce the alcohol content of the spirits to a commercial standard of 42 degrees (84 proof). Many producers believe that calvados would actually benefit from even greater dilution.