as noble rot. In the autumn, the Ciron river produces mist that descends upon the area and persists until after dawn. These conditions are conducive to the growth of the fungus, which desiccates the grape and concentrates the sugars inside. The three main grapes are of this are Sémillon, Sauvignon blanc and Muscadelle. Production costs for this area's botrytized wines are comparatively high. The evaporation and fungus affections produces low yields, one-fifth to one-sixth of that in other Bordeaux regions. The berries are normally harvested individually from the bunch, with pickers going through the vineyards several times between September and November to ensure the berries are picked at their optimal points. The wine is then fermented in small oak barrels, further adding to the cost. Even with half bottles of the First Growths priced at several hundred dollars, these wines still have difficulties turning a profit, and in the mid 20th century, a string of bad vintages drove many growers in the region out of business. Cérons AOC Cérons AOC is an appellation for sweet white wines of similar style as Sauternes, but with no producers as noted as the classified Sauternes properties and therefore with lower prices. On the other hand, the wines are considered superior to those of Graves Supérieures AOC of which Cérons effectively is an enclave. References See also List of vins de primeur Bordeaux wine Bordeaux wine regions Bordeaux wine Bordeaux AOCs Geography of Nouvelle-Aquitaine