Calvados is an apple brandy from the French région of Basse-Normandie or Lower Normandy. Calvados is distilled from specially grown and selected apples, of which there are over 200 named varieties. It is not uncommon for a Calvados producer to use over 100 specific varieties of apple to produce their Calvados. The apples used are either sweet (such as the Rouge Duret variety), tart (such as the Rambault variety), or bitter (such as the Mettais, Saint Martin, Frequin, and Binet Rouge varieties), with the latter category of apple being inedible. The fruit is picked (usually by hand) and pressed into a juice that is fermented into a dry cider. It is then distilled into eau de vie. After two years aging in oak casks, it can be sold as Calvados. The longer it is aged, the smoother the drink becomes. Usually the maturation goes on for several years. A half-bottle of twenty-year-old Calvados can easily command the same price as a full bottle of ten-year-old Calvados.