In the ever-evolving world of winemaking, a new study has uncovered a hidden layer of complexity that could reshape how we understand and value aged wines. Researchers from the Unit of Metabolomics at the Research and Innovation Centre, Fondazione Edmund Mach in Italy, led by Vania Sáez, have identified the presence of sulfonated oligomeric and polymeric procyanidins in red wines. This discovery, published in OENO One, challenges existing methods of analyzing tannin structure and could have significant implications for the wine industry.
Proanthocyanidins, commonly known as condensed tannins, are crucial for the taste, mouthfeel, and aging potential of red wines. The mean Degree of Polymerisation (mDP) is a key metric used to assess the complexity and quality of these tannins. However, the new findings suggest that traditional methods of calculating mDP may not tell the whole story.
The study focused on four single cultivar red wines: Sangiovese, Nerello Mascalese, Sagrantino, and Nebbiolo. The researchers added varying levels of sulfur dioxide (SO2) and stored the wines under different conditions to observe the formation of sulfonated procyanidins. “We found that the epicatechin 4β-sulfonate released after phloroglucinolysis is significantly higher than the free homologue,” Sáez explained. “This indicates the presence of oligomeric and polymeric sulfonated procyanidins in wine, which can affect the calculation of mDP.”
The implications of this research are far-reaching. For winemakers, understanding the true mDP of their wines could lead to more precise blending and aging strategies. “This overestimation of mDP values increases with wine ageing or storage at elevated temperatures,” Sáez noted. This means that wines stored for longer periods or in warmer conditions may have different tannin structures than previously thought, potentially affecting their market value and consumer perception.
The discovery also opens up new avenues for research in wine chemistry. Future studies could explore how sulfonated procyanidins influence wine flavor and mouthfeel, or how different winemaking practices affect their formation. “This is just the beginning,” Sáez said. “There’s so much more to understand about these compounds and their role in wine.”
For the wine industry, this research could lead to new quality control measures and marketing strategies. Wines with higher levels of sulfonated procyanidins might be marketed for their unique aging potential, while winemakers could adjust their use of SO2 to optimize tannin structure. As the industry continues to evolve, understanding these complex compounds will be key to producing high-quality wines that meet consumer demands.
The study, published in OENO One, which translates to “One Wine” in English, represents a significant step forward in wine research. As Sáez and her team continue to unravel the mysteries of wine chemistry, the industry stands to benefit from a deeper understanding of the liquids in our glasses. The presence of sulfonated oligomeric and polymeric procyanidins in red wines is just one piece of the puzzle, but it’s a piece that could change the way we think about wine forever.