New Study Reveals Pressing Dynamics Influence Burgundy Chardonnay Quality

VOLTA Project Sheds Light on Polyphenol Extraction in Winemaking

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When it comes to creating a top-notch Chardonnay in Burgundy, there's a lot more going on than meets the eye. The Bureau Interprofessionnel des Vins de Bourgogne (BIVB) and the Vinventions Oenology team have delved deep into understanding how polyphenol extraction during pressing influences the longevity and quality of these esteemed wines. Let's explore the intricate details and implications of their findings.

Wine longevity, particularly for white Burgundy wines, hinges on a delicate balance of compounds, with polyphenols playing a starring role. Polyphenols, while primarily known for their antioxidant properties, can paradoxically contribute to wine oxidation if not managed properly. The goal of this research was to assess how polyphenol levels change during the pressing of Chardonnay grapes and how these levels affect the wine's overall stability and longevity.

The VOLTA project involved collaboration with around forty partner wineries across Burgundy, covering diverse geographical areas and winery types. Using advanced electrochemical methods, researchers collected data over four vintages (2020-2023), monitoring polyphenol levels from the free-run juice during pressing to the final settling tanks.

Pressing Dynamics and Polyphenol Extraction

Three primary patterns of polyphenol extraction were identified:

  1. High Initial Polyphenol Content: Some presses showed high polyphenol levels right from the start, with little to no increase during the pressing process. These wines often had a consistently high polyphenol concentration in the settling tanks.
  2. Low Initial, Increasing Polyphenol Content: The majority of presses started with low polyphenol levels that increased steadily throughout the pressing. Despite this increase, the levels often remained below the median value typical for Chardonnay musts.
  3. Variable Polyphenol Content: A smaller fraction exhibited low to medium initial polyphenol levels that surged to high levels by the end of pressing.

These findings suggest that the way polyphenols are extracted can vary significantly even within the same grape variety and region.

Pre-Pressing Practices and Their Impact

Interestingly, none of the pre-pressing practices (such as sulfiting, type of harvest, or cooling of the harvest) had a statistically significant impact on the dynamics of polyphenol extraction during pressing. However, the method of harvesting did influence the initial polyphenol levels in the free-run juice. Machine harvesting, for instance, resulted in higher polyphenol levels compared to manual harvesting. This is likely due to the greater mechanical action on the grapes, which promotes more thorough extraction of compounds.

Sulfiting: A Key Player

Sulfiting practices emerged as a significant factor influencing polyphenol levels. When sulfites were applied to the grapes before pressing, polyphenol content in the free-run juice was notably higher. This pre-fermentation sulfiting appears to help extract polyphenols and protect them from oxidation, thereby maintaining their concentration.

Conversely, sulfiting after pressing did not significantly impact polyphenol levels. This suggests that the timing of sulfite application is crucial for optimizing polyphenol extraction and ensuring the desired wine quality.

Real-World Implications for Winemakers

For Burgundy winemakers, these findings offer practical insights into how different practices can influence the final product. While certain techniques like machine harvesting and pre-pressing sulfiting can enhance polyphenol content, the overall dynamics during pressing remain less affected by pre-pressing practices.

This knowledge empowers winemakers to fine-tune their processes, balancing polyphenol levels to create Chardonnay wines that are not only flavorful but also possess greater longevity. It also underscores the importance of continuous monitoring and adaptation to vintage-specific conditions, ensuring that each bottle of Burgundy Chardonnay reflects the best possible expression of its terroir.

Looking Forward

The VOLTA project's ongoing research aims to further elucidate the connection between polyphenol content and the oxidative stability of wines. By understanding these relationships more deeply, Burgundy winemakers can continue to enhance the quality and aging potential of their white wines, preserving the legacy and excellence of this renowned wine region.

In conclusion, while the process of crafting a high-quality Burgundy Chardonnay is complex and nuanced, the insights gained from studies like VOLTA provide invaluable guidance. By focusing on key practices and understanding their impacts, winemakers can continue to produce wines that stand the test of time, offering consumers the exceptional experience that Burgundy wines are celebrated for.

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