Wine lees are the solid remnants that settle at the bottom of the fermentation vessel during the winemaking process. They are a mixture of spent yeast cells, grape particles and other organic matter.
Some wines, like Champagne, certain Chardonnays and Muscadets, are aged on their lees, a process known as “sur lie” aging. This can add depth, richness, and complexity to the wine. The breakdown of yeast cells in lees releases compounds that can impart biscuity, brioche and toasty notes. Other traditional method sparkling wines, such as Cava from Spain or Crémant from various regions in France, can also exhibit these flavours.
If you want to know more, there’s an excellent article The Science of Lees Aging.
