From waste to worth: wine lees composition and applications in research and industry

In enology, the term "wine lees" refers to the sediment that settles at the bottom of wine containers (e.g., tanks, barrels, or bottles) after fermentation and during the aging of wine. They consist mainly of biomass from yeast cells -also lactic acid bacteria-, grape solids, and particles of various compositions that precipitate out of wine over time. Wine lees are often used in the aging process because of their antioxidant properties and the enhancement of the sensory properties of wine. In terms of quantity, wine lees are the second most abundant by-product of winemaking, after grape pomace. Recently, wine lees are increasingly being recognized as a valuable resource within the circular economy, being used for the production of bioactive compounds, biofuels, cosmetics, and organic fertilizers, among others. This approach not only contributes to the sustainability of the wine industry but also reduces the environmental impact of the waste generated during winemaking. This review provides an overview of the properties and potential uses of the wine lees reported to date.