Definition: Lees refer to the thick sediment that floats to the bottom during the wine's fermentation process. The lees consist of the dead yeast cells, grape skin and seed fragments and various grape solids that separate from the juice and go with gravity to the bottom of the barrel or fermentation tank. Winemakers will occasionally stir the lees during fermentation to conjure up additional contact with the grape juice and solids.

This stirring of the lees gives more body and flavor to the final wine.