How to reduce smoky taste in wine: innovative methods for removing undesirable volatile compounds from fire-exposed grapes

Smoke ta fires, which are increasingly affecting winegrowing regions due to climate change, can significantly impact wine quality. Grapes exposed to smoke absorb volatile compounds, such as phenols, which can impart an unpleasant taste to the wine. The most common manifestation is a smoky, ashy, or medicinal taste, which can greatly diminish the quality and value of the wine. However, recent research published in the Journal of Agricultural and Food Chemistry explores new methods for reducing this problem using molecularly imprinted polymers (MIPs).

Innovations in removing undesirable compounds
MIPs are synthetic materials designed for selective binding of specific compounds. In this case, the goal is to remove phenols causing smoky taste while retaining desirable aromas and flavors. Researchers added MIPs to wine at different stages of production—during and after fermentation—and analyzed the results. They specifically focused on removing compounds such as guaiacol, 4-methylguaiacol, and cresol, which were identified as key carriers of smoky taste.

Adding MIPs after fermentation proved to be more effective, as the reduction in undesirable compound concentration was significant, with minimal impact on wine color and aromas. Additionally, the regeneration of MIPs, achieved by rinsing after the extraction of smoky compounds, allowed for their reuse, reducing costs and increasing process sustainability.

Ozonation and other methods as additional options
Besides MIPs, research has shown that post-harvest ozonation can also be effective in reducing smoky taste in wine, especially when used on grapes that are moderately exposed to smoke. Ozonation can reduce the concentration of phenols and their glycosides by up to 25-30%. Although results are not always statistically significant, ozonation still offers additional opportunities for reducing undesirable flavors in wine, particularly when combined with other methods like MIPs.

However, despite these efforts, it is important to note that no method is entirely effective in removing smoky compounds without affecting other wine characteristics. The effectiveness of each method can vary depending on the degree of grape exposure to smoke, which is a challenge that winemakers must consider when choosing strategies for wine treatment.

Given the increasing occurrence of smoke ta fires in winegrowing regions, research like this offers valuable tools for mitigating the impact on wine. The application of molecularly imprinted polymers, along with other techniques such as ozonation, provides promising results but requires careful consideration to achieve a balance between removing undesirable compounds and preserving wine quality.

Research continues to further optimize these methods and tailor them to the specific needs of winemakers facing this challenge.

Source: American Chemical Society