Named after the town of Cognac in France, cognac is a variety of brandy. It is produced in the wine-growing region surrounding the town from which it takes its name, in the French Departments of Charente and Charente-Maritime. For a distilled brandy to bear the name Cognac, an Appellation d'origine contrôlée, its production methods must meet certain legal requirements. In particular, it must be made from specified grapes (see below), of which Ugni Blanc, known locally as Saint-Emilion, is the one most widely used at the present time. In addition, the brandy must be twice distilled in copper pot stills and aged at least two years in French oak barrels from Limousin or Tronçais. Cognac matures in the same way as whiskies and wine when aged in barrels, and most cognacs are aged considerably longer than the minimum legal requirement.