"Sauternes is famous for its sweet white wine, made from Sémillon, Sauvignon blanc, and Muscadelle grapes. The sweetness comes from the Botrytis cinerea fungus, or “noble rot”, that partially turns the grapes into raisins.
Sauternes wines balance sweetness and acidity, with honey and apricot notes. Château d’Yquem is perhaps the most well-known, being the only premier cru supérieur classified wine in the region.
The Barsac commune within Sauternes has its own appellation. These wines are usually drier and less full-bodied than those from the rest of Sauternes." - Airoldi
Map courtesy: Vins de Bordeaux