Petit Chablis is an appellation created in 1944 for dry white wines made from Chardonnay in Chablis and the surrounding communes. It covers vineyards not included in the standard Chablis, Chablis Premier Cru and Chablis Grand Cru titles.
There are 729 hectares (1750 acres) of vineyards in the Petit Chablis appellation. This compares with 3156ha (7574 acres) for generic Chablis. As in the other Chablis appellations, the La Chablisienne co-operative is the biggest player in Petit Chablis production. The organisation makes several cuvées from 266ha (658 acres) of members' plots.
The key factor behind the Chablis hierarchy is the soil in which the vines sit. While the more respected wines come from sites with Kimmeridgian soils, Petit Chablis is produced from vineyards planted in Portlandian soils. The difference between the two soil types is rather subtle. However, the balance of clay and limestone is a key variable of the Chablis region.
Due to the topography and geology of the Chablis area, Portlandian soils are most commonly found on higher ground. Consequently, most Petit Chablis sites are located on plateaux above slopes which are home to Premier or Grand Cru. The obvious example is the plateau directly west of Chablis town, immediately above the slopes of the Grand Crus. Here, the geographical distance between the most and least prestigious Chablis vineyards is tiny.