Have you had a white wine or a sparkling wine and thought to yourself, This is a bread bomb!
It smells yeasty and lands on your palate like a liquified brioche - bready and nutty with a creamy mouth feel. If so, there is every chance that the wine you just had has been aged sur lie.
Sur lie (pronounced sewr-h lee) is French for “on lees.” Lees are basically solid remnants from the winemaking process. There are generally two kinds of lees - gross lees and fine lees. Gross lees are mostly made up of grape debris. They are larger and tend to settle easily to the bottom of the wine. Fine lees refer to the sedimentary residue that consists primarily of dead yeast cells. They are smaller and can be easily stirred into a cloudy swirl before being drawn downwards by gravity.
Gross lees are often removed (or racked off) during the winemaking process. Prolonged contact with gross lees can contribute to off-flavors in wine. The funk may come from decomposing grapes, spoilage organisms, or excess sulfur found on the harvested grapes.
Lees left after racking
Fine lees, on the other hand, bring about desirable texture, flavors, and complexity to the wine. As yeast cells break down, they release mannoproteins, polysaccharides, fatty acids, and amino acids. Together these compounds contribute to the aromas and flavors of brioche, honey, and nut. They also create a buttery creamy mouthfeel while softening the tannins. As a bonus, fine lees are also reductive in nature and protect the wine from oxidation.
Bâtonnage, Stirring Up the Lie
There are two different methods for aging wine on lees: 1) keeping the lees at the bottom of the barrel, or 2) stirring the lees periodically to ensure homogenous and consistent contact with the wine. The latter approach is known as bâtonnage (pronounced bah-too-naj). It is believed that both processes give pretty much the same result with some stylistic differences. See the video on bâtonnage below.
When considering whether to practice bâtonnage, the winemaker has to determine how much lees contact is needed to bring out the desired characteristics in the wine. Major Burgundy house Maison Louis Latour uses little to no bâtonnage on their Chardonnay, believing that the lees-to-wine ratio in the barrel does not always require it. For wineries that choose to practice bâtonnage, they vary in how frequent and how long to stir the lees, walking the fine line between over and under-stirring.
Famous Sur Lie Wines
Sur lie wine aging is believed to date back to the Roman Republic era, as documented by Cato the Elder. In modern winemaking, the two regions famous for aging their wines on lees are Burgundy and Champagne. White grape varieties that benefit from aging on the lees are Chardonnay, Muscadet, Chenin Blanc, Pinot Blanc, Pinot Gris, and other crisp white wines with high acidity.
White Burgundy - Made with 100% Chardonnay grapes, white Burgundy is often credited as the originator of sur lie aging in modern winemaking. After harvest, the grapes are pressed, and the juice goes into the barrels without solid grape debris. Alcoholic fermentation starts in the barrels, followed by malolactic fermentation. Since there are no gross lees, the wine does not need to be racked till the next spring. After racking, some amount of lees is retained in the wine for another 10 to 18 months of barrel aging. Bâtonnage is optional.
2022 Maison Castel Chablis, a white Burgundy
Champagne - There are three main grape varieties in a Champagne - Chardonnay, Pinot Noir, and Pinot Meunier. With the exception of making a rosé Champagne, the harvested grapes are pressed and clarified to obtain a clear juice. The juice then goes into stainless steel vats to start alcoholic fermentation. The use of oak and malolactic fermentation is optional.
NV Laurent-Perrier Ultra Brut
When fermentation is complete, the wine is bottled with the addition of liqueur de tirage, which consists of still wine, sugar, and yeast. This starts off a secondary fermentation to create carbonation. Thereafter, the wine goes through sur lie aging in the bottle for a minimum of one year for a non-vintage Champagne and three years for a vintage Champagne. Bâtonnage is non-existent.
Aging on Lees in Barrel vs. Bottle
Wine aged on lees in the barrel benefits from the aroma compounds that are extracted from the oak. These add notes of caramel, vanilla, and spice. Additionally, there is space to maneuver a baton or any long metal tool to stir up the lees if bâtonnage is so desired.
As for aging wine on lees in the bottle, bâtonnage is virtually impossible. Also, there is also the challenge of removing the lees when aging is complete. This is achieved through a process called riddling, where wine bottles with lees are first placed at 35° angle on a wooden rack. The bottles are then gradually shaken and rotated at an increasing angle, with gravity pulling the lees to the lowest part of the bottles. When the bottles are virtually upside down, the lees that have settled in the bottlenecks are then frozen and removed. Voila!
Riddling rack
Now you have learned about a few things about lees - gross versus fine lees, to stir or not to stir lees, to age on lees in a barrel or a bottle. The next time you encounter a yeasty, bready wine, you may proclaim with confidence, “Surely, this wine is aged sur lie!”