What does 'bâtonnage' refer to in winemaking?

Bâtonnage is a technique in winemaking that specifically refers to the stirring of the lees, which are the sediment consisting of dead yeast cells and other particles, that settle at the bottom of a fermentation vessel after fermentation. This practice is particularly important for wines that undergo malolactic fermentation, as it can enhance the wine's complexity and mouthfeel. By stirring the lees back into suspension, the winemaker can promote the development of additional flavors and aromas, as well as provide a creamy texture to the wine through the release of mannoproteins, which result from the yeast cells breaking down.

In contrast, the fermentation of skins with juice is a different process used primarily for red wines, where the color and tannins are extracted from the grape skins during fermentation. Aging in oak barrels is a common practice that influences the flavor and aromatic profile of wine, but it does not involve stirring of the lees. The addition of sugar for sweetness refers to a different technique known as chaptalization, which is used to increase the alcohol content of a wine but is not associated with bâtonnage either.