Sauternes is a sort after French sweet wine from the Sauternes region of the Graves section in Bordeaux, France. Sauternes is made from Semillon, Sauvignon Blanc, and Muscadelle grapes that have been affected by Botrytis cinerea - noble rot. This causes the grapes to become partially dehydrated, resulting in concentrated and distinctively flavoured. Due to its climate, Sauternes is one of the few wine regions where infection with noble rot occurs frequently. This said there are varying harvests from vintage to vintage. Sauternes wines can be expensive, due largely to the high cost of production.
Sauternes wine region comprises five communes - Barsac, Sauternes, Bommes, Fargues and Preignac. To qualify for the Sauternes label, the wines must have a minimum 13% alcohol and pass a tasting exam, though there is no regulation on the exact amount of residual sugar that the wine needs. In the winery grapes are treated very gently during pressing and fermentation frequently takes place in oak barrels with the house style dictating the amount of new oak used. After fermentation the wine can be aged from 18-36 months in oak prior to release.
Semillon can make up to 75-90% of a Sauternes blend, though weather conditions can effect the final composition as the grapes are not evenly affected by noble rot. Semillon is very easily affected due to its thin skin, though Sauvignon Blanc is normally affected first. Sauvignon Blanc is valued for the acidity that it can add and its ability to harmonize with Semillon. Muscadelle is used in very small quantities, if at all, and contributes aromatic qualities.