Revolutionizing Canned Wine: Scientists Discover a Solution to Unpleasant Odors Chris Lehoux, June 1, 2024 After complaints of foul odors resembling rotten eggs, researchers at Cornell University identified the cause and are now developing advanced materials to enhance canned wines. Canned wine, a rapidly expanding sector in wine packaging innovations, attracts a younger demographic with its portability, eye-catching designs, and eco-friendliness. These products see a surge in sales during the spring and summer seasons, favored at outdoor gatherings for their convenience and single-serve format, contrasting traditional glass bottles. However, the rising popularity of canned wines has brought about a marketing challenge as some users have noticed an unpleasant sulfur-like odor upon opening the cans. Although the wine’s quality remained uncompromised, this issue raised concerns among vintners who had opted for cans over glass bottles. A group of winemakers from New York sought assistance from the Cornell University College of Agriculture and Life Sciences. Professors Dr. Gavin Sacks and Dr. Julie Goddard began investigating this phenomenon in 2018. Their research group has published numerous studies in the American Journal of Enology and Viticulture, with their latest publication in February 2024. Their discoveries not only pinpointed the source of the odor in canned wines but also led to the development of advanced materials that better preserve the wine within cans. The investigation by the research team at Cornell began with identifying the cause behind the bitter odor emanating from canned wine. Although wineries confirmed their wine remained high quality when stored in standard containers, the issue persisted with canned versions. Collaborating closely with the can producers employed by these wineries, the researchers pinpointed the problem’s source. It’s established that none of the chemical substances in soft drinks or beer react adversely with aluminum. However, wine typically consists of about 0.5 to 1 ppm of sulfur dioxide (SO2), which, though minimal, effectively prevents oxidation and is sometimes added for preservation, besides naturally occurring during the fermentation process. Unbeknownst to vintners, the prolonged interaction between SO2 and aluminum instigates a chemical reaction that produces hydrogen sulfide (H2S), a compound notorious for imparting a foul, sulfur-like stench to liquids. “In instances where the wine had more than 0.5 ppm of molecular SO2, significant increases in H2S levels, contributing to the rotten egg odor, were noticed within four to eight months,” announced Sacks in a press release. With this newfound understanding, the Cornell research team quickly advised winemakers on strategies to mitigate the unpleasant aroma. However, completely removing SO2 was not deemed feasible due to the increased risks of oxidation and microbial infection, which could result in spoilage of the wine in cans. “We began by encouraging wineries to target the lower spectrum of their comfort zone,” stated Sacks. “Naturally, this could lead to more issues with oxidation. However, the advantage is that cans provide a hermetic seal. If properly sealed during the canning process, they shouldn’t allow any air to enter, which is a key reason why brewers prefer them. This factor is crucial for preventing oxidation.” According to Sacks and his colleagues, consumer preferences might also play a role in the perception of odors. “It’s interesting that molecular SO2 levels are typically lower in red wines compared to white wines,” Sacks pointed out. “This creates an irony since molecular SO2 ends up being the main contributor to odor in canned wines. Since cans are often associated with cheaper and less prestigious wines, most companies avoid canning red wines. When you visit a store, it’s more common to find sparkling wines, white wines, and rosés in cans, but these are exactly the types that tend to have more issues.” The Cornell team, funded by the U.S. Department of Agriculture’s National Institute of Food and Agriculture, is exploring an intriguing solution to address the SO2 problem: plastics. Despite seeming contrary to the eco-friendly aspect of can recyclability, they are developing recyclable, food-grade polymers for aluminum can linings. These polymers aim to prevent the chemical reactions that produce H2S and stabilize the wine during extended storage. To aid in the design of these innovating can liners, Sacks and Goddard have enlisted Dr. Héctor Abruña, a professor in chemistry at the College of Arts and Sciences. Their focus is on maintaining the recyclability of the liners, minimizing manufacturing costs, and avoiding additional chemical interactions with the wine. Research is ongoing, but the dedication to enhancing canned wine technology remains steadfast.” “I thought aluminum cans were boring until I started working on them,” said Sacks. “The current generation of wine consumers coming of age now, they want a beverage that’s portable and they can bring with them to drink at a concert or take to the pool. That doesn’t really describe a cork-finished, glass-packaged wine, but it describes a can very nicely.” Stay on top of important wine stories with Wine Spectator’s free Breaking News Alerts. About the Author: Chris Lehoux Meet Chris Lehoux, an experienced wine connoisseur and dedicated blogger with a deep passion for all things wine-related. 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