Although based in Barsac the wine is classified as Sauternes AC. Sauternes.which is in the Graves wine region is made from Sémillon, Sauvignon blanc, and Muscadelle grapes that have been affected by Botrytis cinerea, also known as noble rot. This causes the grapes to become partially raisined, resulting in concentrated and distinctively flavoured wines.  Wines from Sauternes, especially the Premier Cru Supérieur estate Château d’Yquem, can be very expensive, due largely to the very high cost of production. Barsac lies within Sauternes, and is entitled to use either name.