Lees are the deposits that settle during or after fermentation. They consist mainly of dead yeast cells, grape solids and other suspended material. In winemaking, lees are commonly divided into gross lees and fine lees because they have different compositions and uses. Some wines are separated from the lees soon after fermentation, while others are deliberately matured in contact with selected fine lees.
Gross lees are the heavier deposits of grape skins, pulp, seeds, tartrates and yeast material that settle soon after fermentation. They are generally removed relatively early to reduce the risk of unwanted aromas or microbial problems. Fine lees consist mainly of smaller yeast cells and fine particles that settle more slowly and may be retained for maturation.
Ageing wine on fine lees can contribute texture, body and savoury complexity. As yeast cells break down through autolysis, they release compounds that may contribute creamy, bready, nutty or pastry-like characteristics. The effect depends on time, temperature, wine style and lees management.
Bâtonnage is the stirring of fine lees back into suspension. Racking transfers wine away from settled deposits. A winemaker may rack off gross lees but retain selected fine lees for further maturation.
Example: a Chardonnay may be matured on fine lees in barrel, with occasional bâtonnage to develop texture, while a fresh aromatic white may be racked off the lees to preserve a cleaner fruit profile.
Chef’s note: lees contact can enhance texture, but it is not automatically beneficial. Poorly managed or unsuitable lees can contribute unwanted aromas and instability.
This term is one of hundreds covered in depth across OCS courses, learning paths, and 1-on-1 coaching with Chef Eric.
