New Tools in the Fight Against White Wine Oxidation

Oxidative stability is a critical aspect of maintaining the quality of white wines, essential for preserving their color, aroma, and flavor. Oxidation can significantly deteriorate these attributes, making it crucial for winemakers to manage this process meticulously. Maria Nikolantonaki from the Université de Bourgogne recently presented an in-depth analysis of current enological practices and tools aimed at addressing this issue. This article explores these methods and the ongoing advancements in the field.

Oxidation in white wines occurs when the wine comes into contact with oxygen, triggering chemical reactions that alter its components. The adverse effects of oxidation include color changes towards darker hues, loss of fresh fruity aromas, and the development of unpleasant smells and tastes, such as those resembling oxidized apples or rancid nuts. Achieving oxidative stability involves minimizing these changes, thereby extending the wine's shelf life and enhancing its overall quality.

One of the most commonly used methods to control oxidation is the addition of sulfur dioxide (SO2). SO2 is an effective antioxidant that protects wine by reacting with oxygen and other oxidative compounds. However, excessive use of SO2 can negatively impact the wine's perception and pose health risks to consumers. Consequently, there is a continuous search for more natural and sustainable alternatives. Among these are phenolic compounds, which act as natural antioxidants found in grapes and other plant extracts.

Managing oxygen throughout the winemaking process is another critical factor. From grape harvesting to bottling, controlling oxygen exposure can prevent premature oxidation. In the winery, techniques such as inertization are employed, which involves displacing oxygen around the wine with inert gases like nitrogen or argon. Additionally, the design of bottle closures, which serve as barriers to oxygen, is crucial for maintaining wine stability during storage and distribution.

Technological Innovations in Monitoring Oxidation

Technology plays a significant role in monitoring oxidation. Winemakers can use advanced equipment to measure dissolved oxygen levels and the wine's antioxidant capacity at various stages of production. This allows for real-time adjustments to enological practices, ensuring optimal protection against oxidation.

Continuous education and knowledge exchange between winemakers and scientists are vital for improving the oxidative stability of white wines. Research in this area is advancing rapidly, offering new tools and techniques that can be applied in enological practice. Maria Nikolantonaki emphasizes the importance of staying updated with these advancements and adopting an integrated approach that combines science, technology, and traditional practices to optimize wine quality.

In her recent study, Maria Nikolantonaki presented various tools used to characterize the antioxidant metabolome of white wine. This metabolome, which determines the oxidative stability of white wines, begins to develop from the start of the winemaking process. Her research highlights the impact of pressing conditions and barrel aging on the antioxidant metabolome of yeasts in wines, demonstrated through results obtained over three consecutive vintages of Chardonnay vinification.

Following Maria's presentation, Remi Schneider from Oenobrands focused on the development of yeast derivatives that enhance the oxidative stability of white wines. These derivatives were tested under different conditions, including temperature variations, the presence or absence of oxygen, and sulfur dioxide. In collaboration with the University of Burgundy, they studied a formulation of various yeast derivatives (Extraferm D'fend), composed of 80% inactive yeast and 20% autolyzed yeast. This formulation can be used not only in white wines but also in rosé wines, base wines for sparkling wines, and wines without added sulfites.

Oxidative stability in white wines is a fundamental area of study and practice in modern enology. The tools and strategies discussed by experts like Maria Nikolantonaki and Remi Schneider allow winemakers to protect their wines from oxidation, ensuring they reach consumers in the best possible condition.

Understanding and controlling oxidation remains at the forefront of producing high-quality white wines. With continuous advancements and collaborative efforts between research and practice, the enological community is well-equipped to tackle the challenges posed by oxidation, ensuring the longevity and excellence of white wines.