Types of Lees
- Gross lees — heavy sediment that settles quickly after fermentation; usually removed within days
- Fine lees — lighter yeast deposits that settle over weeks; these are the beneficial lees used in sur lie aging
Sur Lie Aging
When wine rests on its fine lees, a process called autolysis occurs: dead yeast cells break down and release amino acids, mannoproteins, and polysaccharides. This enriches the wine's texture, adds brioche and bread-dough notes, and improves mouthfeel.
Bâtonnage
Winemakers often stir the lees (bâtonnage) to increase contact between wine and sediment. This technique is common in barrel-fermented Chardonnay and contributes to a richer, creamier palate.
Where Lees Aging Shines
Champagne must age on its lees for a minimum of 15 months (36 months for vintage). Muscadet sur Lie is a Loire Valley classic. Many premium white Burgundies also benefit from extended lees contact.