Les Clos is the largest and most widely known of the seven climats of the Chablis Grand Cru white wine appellation. It covers a single, southwest-facing slope above the town of Chablis itself, and is planted exclusively to the Chardonnay grape variety. Chablis Les Clos wines are generally more powerful and intense than the other Grand Crus, and are often associated with ripe stonefruit, orange peel and honey. With a tendency to be more closed in their youth than those from the other climats, they are famous for their long-term aging potential, showing a balance between power and finesse.
The 66-acre (27ha) vineyard is situated at the southern end of the Grand Cru hill, between the similarly revered Valmur climat and the less-famous Blanchots site. It rises sharply and uniformly from the valley floor to the hilltop above, creating one of the most homogenous terroirs on the Grand Cru hill, and thus the most consistent wines.
The aspect of Les Clos – facing toward the southwest – has long been considered one of the vineyard's most important traits. The vines are in full view of the intense afternoon sunshine that affords good ripening opportunities, ensuring there are optimum levels of sugars and phenols in the grapes prior to harvest. This is tempered by the cool continental climate of north Burgundy, and so this ripeness never comes at the expense of the fresh, racy acidity that Chablis wines are famous for. Les Clos Grand Cru wines are arguably the best example of this balance in Chablis.
The Les Clos vineyard has white, stony soil with high levels of limestone and clay, providing a well-drained site that is perfect for viticulture. This soil is derived from the Kimmeridgian marl that underlies much of Chablis, a relic from an ancient sea which once covered northern France (evidenced by the thousands of fossilized oyster shells found in the vineyard). The soil's rapid drainage means that vines have to reach deep into the limestone for water. This is often considered the reason for the intense minerality in Les Clos wines.
The Les Clos Grand Cru vineyard is usually credited as the best in the region, and it is widely believed that this was the first vineyard planted in Chablis. Its name is derived from the walls that originally surrounded the vineyard – clos being French for "enclosed area". Over time, the term has come to refer particularly to walled vineyards: the Clos de Vougeot vineyard in Burgundy and Krug's Clos du Mesnil vineyard in Champagne are two famous examples.