Can Fumaric Acid Rescue Wine from the Heat? New Study Says Yes

Recently, the International Organisation of Vine and Wine (OIV) approved the use of fumaric acid in winemaking, a decision poised to revolutionize the industry. This organic acid is employed to inhibit malolactic fermentation (MLF), a process that can diminish the wine's acidity, compromising its freshness and longevity. The approval comes at a critical time when global warming is increasingly impacting wine quality, particularly in warmer regions.

Malolactic fermentation is a natural biochemical process wherein lactic acid bacteria convert malic acid (which has a sharp, tart taste akin to green apples) into lactic acid (which is softer, like the acid in milk). This transformation can smooth out the wine's taste, but it often results in lower acidity and diminished freshness—an outcome particularly problematic for white, rosé, and sparkling wines.

By adding fumaric acid to the wine, winemakers can effectively prevent MLF, thereby preserving the wine's natural acidity. This not only results in a fresher taste but also enhances the wine's stability and microbial safety. Wines with higher acidity are less prone to spoilage and undesirable microbial activity, issues that can arise when the pH is too high.

A research team from the Polytechnic University of Madrid conducted a comprehensive three-year study to assess the effectiveness of fumaric acid across various wine types and grape varieties, including Tempranillo and Garnacha for reds, Tempranillo for rosés, and Viura for whites. The study comprised four distinct trials: spontaneous MLF, inoculated MLF, spontaneous MLF with fumaric acid, and inoculated MLF with fumaric acid. The findings were promising, indicating that a dosage of 600 mg/L of fumaric acid could reduce the wine's pH by approximately 0.1 units.

In trials where fumaric acid was utilized, the wines retained their desired acidity levels while maintaining low volatile acidity (responsible for off-flavors), ranging between 0.05 to 0.22 g/L. For red wines, the preservation of acidity without excessive softening was beneficial, particularly in warmer climates where acidity tends to decrease. White and rosé wines retained their freshness and zesty profile, crucial for a refreshing palate. For sparkling wines, controlling MLF during the secondary fermentation was vital for maintaining quality and stability, with fumaric acid proving effective in this regard.

The introduction of fumaric acid as a tool for managing MLF offers winemakers enhanced control over the fermentation process, ensuring that the wine's natural acidity and freshness are preserved. This capability is especially pertinent in the context of global warming, where higher temperatures can adversely affect wine quality by accelerating the loss of acidity and increasing the risk of spoilage.

The Madrid study underscores the versatility and efficacy of fumaric acid across different wine types and grape varieties, providing a valuable asset for producing high-quality wines consistently. This innovation supports the wine industry's adaptation to climatic challenges, safeguarding the sensory qualities that consumers cherish.

The adoption of fumaric acid in winemaking marks a significant advancement in the industry's ability to adapt to climate change while maintaining high standards of wine quality. By inhibiting malolactic fermentation, fumaric acid preserves the crucial acidity and freshness of wines, ensuring they remain vibrant and stable. As global temperatures rise, such innovations are not just beneficial but essential for the sustainability and excellence of winemaking. The research from the Polytechnic University of Madrid offers a robust endorsement of this practice, paving the way for widespread application and setting a new standard in the art and science of winemaking.