Winemakers take several precautions to prevent oxidation during the aging of sparkling wine on lees. This process is crucial to maintain the freshness, complexity, and quality of the final product.
Use of Sulfur Dioxide
Sulfur dioxide is a common antioxidant used by winemakers to prevent oxidation in wine. It is added in small doses to the wine during various stages of production, including during the aging process on lees. Sulfur dioxide helps to inhibit the growth of unwanted microorganisms and prevent oxidation, ensuring the wine retains its freshness and flavor.
Topping Up the Wine
Winemakers regularly top up the barrels or tanks containing the sparkling wine on lees to minimize the ullage (the empty space between the wine and the container’s top). By keeping the wine in contact with the lees and minimizing exposure to air, winemakers can reduce the risk of oxidation.
Using Stainless Steel or Neutral Oak Barrels
The choice of aging vessel can also impact the level of oxidation in sparkling wine during the lees aging process. Stainless steel tanks or neutral oak barrels are often preferred for aging sparkling wine, as they are less permeable to oxygen compared to new oak barrels. This helps to minimize oxidation and preserve the wine’s freshness.
Frequent Lees Stirring
During the aging process, winemakers regularly stir the lees in the wine to enhance flavor development and mouthfeel. This process, known as batonnage, helps to extract compounds from the lees and integrate them into the wine. By keeping the lees in suspension and in contact with the wine, winemakers can mitigate the effects of oxidation.
Monitoring and Controlling Temperature
Temperature control is essential in preventing oxidation during the aging of sparkling wine on lees. Winemakers carefully monitor and regulate the temperature of the aging cellar to ensure it remains stable and cool. Lower temperatures can help slow down oxidation reactions and preserve the wine’s freshness and vibrancy.
Protective Gases
Some winemakers use protective gases, such as nitrogen or argon, to create a blanket over the surface of the wine in the aging vessel. This inert gas layer helps to prevent oxygen from coming into contact with the wine, reducing the risk of oxidation.
Avoiding Racking
Winemakers may choose to minimize the number of rackings (transferring the wine from one vessel to another) during the aging process to reduce the wine’s exposure to air. By keeping the wine in the same vessel for an extended period, winemakers can limit oxidation and preserve the wine’s freshness.
Regular Analysis and Testing
Winemakers conduct regular analysis and testing of the wine during the aging process to monitor its progress and detect any signs of oxidation. By staying vigilant and proactive, winemakers can take corrective actions if necessary to prevent oxidation and maintain the wine’s quality.