Lees

Lees meaning in wine

Lees are the sediment composed primarily of dead yeast cells, grape solids, and tartrate crystals that settle at the bottom of fermentation vessels after alcoholic fermentation is complete. This natural byproduct of winemaking plays a crucial role in developing wine’s character and complexity. When wines are aged sur lie (on the lees), winemakers deliberately leave the wine in contact with this sediment for extended periods, typically 3-12 months or longer. During this process, the dead yeast cells undergo autolysis, gradually breaking down and releasing compounds such as amino acids, proteins, and mannoproteins into the wine. This contact imparts distinctive qualities including enhanced mouthfeel, increased body, and subtle creamy textures, particularly prized in white wines like Chardonnay and Champagne. Bâtonnage, the French technique of stirring the lees, further accelerates this process by keeping the sediment in suspension and maximizing contact with the wine. The practice also contributes to malolactic fermentation and can add complex flavors ranging from bread-like and nutty to mineral notes. While traditionally associated with premium white wine production, some red wines also benefit from lees contact, gaining additional tannin integration and textural refinement.