Sauternes is renowned for its production of noble rot wines, but truly exceptional examples can only be made in years with favorable weather conditions and when producers are able to harvest only botrytised grapes. Even in good years, if the harvest period is too dry, the proportion of noble rot-affected grapes may be low. In such cases, even if the grapes are highly concentrated in sugar, the resulting wine may not fully embody the typical character of Sauternes.
Harvesting is generally done in several passes (known as tries) to select grapes affected by noble rot, but due to the risks involved in waiting too long, some producers may opt for a single harvest once a sufficient level of botrytisation has occurred. In years when weather conditions are less favorable and the proportion of botrytised grapes is too low to achieve the desired sugar levels, chaptalisation (the addition of sugar) may be employed.
The Sauternes appellation includes five communes: Barsac, Bommes, Fargues, Preignac, and Sauternes. Wines made exclusively from grapes grown in Barsac may also be labeled under the Barsac appellation.