Lees (fermentation)

Lees refers to the deposits of dead or residual yeast and other particles that precipitate, or are carried by the action of "fining", to the bottom of a vat of wine after fermentation and aging. The yeast deposits in beer brewing are known as trub. However, yeast deposits from fermentation in a distillery are usually referred to as spent wash, pot ale, or vinasse.

History

The practice of using lees in winemaking has been around for centuries, with the earliest recorded mention in the Roman Empire. The Romans discovered that fine wines could be made by leaving the wine to sit on the lees, a method that contributed to the development of the rich, full-bodied style of Roman wines.

Process

In wine production, lees are residual yeast and other particles that precipitate, or are carried by the action of "fining", to the bottom of a vat of wine after fermentation and aging. The lees remain in contact with the wine during both fermentation processes, and they continue to have an effect on the wine even after fermentation has stopped.

Sur Lie Aging

Sur lie aging is a technique used in winemaking where the wine is allowed to remain in contact with the lees for an extended period. This can lead to a greater complexity of flavor and aroma, as well as a creamier texture. The process is used in the production of many types of wine, including Chardonnay, Champagne, and Muscadet.

Bâtonnage

Bâtonnage is the French term for the process of stirring the lees back into the wine. This is done to prevent the lees from settling and to promote the extraction of desirable compounds from the lees into the wine. The process can enhance the body, flavor, and aroma of the wine.

Lees in Brewing

In brewing, the lees are referred to as trub (also spelled trüb). This sediment consists primarily of heavy fats, proteins and inactive yeast. The trub is not typically used in brewing, but can be used in the making of bread and other food products.

Lees in Distilling

In distilling, the lees are referred to as spent wash or pot ale. This is the liquid residue that remains in the still after distillation. Spent wash is high in nutrients and is often used as a fertilizer.

See Also

• Yeast
• Fermentation
• Wine
• Brewing
• Distilling

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