Sur Lie Aging

Sur lie is the French term for “on the lees”. Many wines are aged with a portion of the spent yeast remaining in contact with the wine. The wines develop a distinct leesy aroma and often a creamy mouthfeel as well. This technique is often employed with white wines that undergo barrel fermentation. It is especially popular as the Burgundy style of Chardonnay production. The yeast will naturally settle during ageing and it periodically is stirred to re-suspend it into the wine. The lees has the potential to develop reductive characters and this stirring helps prevent that by supplying small amounts of oxygen and exposing more of the lees to the wine environment. The yeast lees have antioxidant properties and can help prevent oxidative ageing of the wine. They also serve as a mild fining agent that can help reduce harsh or bitter flavors. Nutrient compounds also begin to leak from the dead yeast cells and help promote the growth of malolactic bacteria.