Sauternes is where arguably the world's finest sweet white wines are produced. The Sauternes appellation consists of five communes: Barsac, Preignac, Bommes, Fargues and Sauternes itself. Barsac is also an appellation in its own right.
Sauternes literally has an atmosphere different from any of the other major communes. At the southern tip of the Graves, close to the Garonne, not only is the land hillier and decidedly more bucolic but it also enjoys a specific microclimate of evening autumn mists which linger until well into the following day, unless burnt off by warm sunshine. The mists are caused by the cool, spring-fed waters of the Ciron River meeting the warmer tidal Garonne, and the result is an ideal environment for the growth of the mould botrytis cinerea. When its arrival is felicitous, it feeds on the water in the ripe grapes, dehydrating them and leaving sweet, shriveled fruit.