Aluminum beverage cans have long been utilized for various drinks, but when it comes to wine, there have been notable challenges. Chief among them is the occasional unpleasant odor resembling rotten eggs emanating from canned wine. Fortunately, researchers have identified the root cause of this issue and devised effective solutions. The breakthrough came through extensive sampling and testing, as depicted in the accompanying image.
The primary culprit behind the foul smell was found to be molecular sulfur dioxide (SO2), a compound commonly employed in winemaking for its antioxidant and antimicrobial properties. Despite the presence of a thin plastic lining inside beverage cans, molecular SO2 could still interact with the surrounding aluminum, leading to the formation of hydrogen sulfide (H2S)—the notorious rotten egg odor—at even low concentrations.
Research indicated that canned beverages containing over 0.5 parts per million (ppm) of molecular SO2 were prone to experiencing a noticeable increase in hydrogen sulfide within four to eight months. Given that most wines aim for approximately 0.5 ppm of SO2, canned wines were susceptible to this issue sooner rather than later, with the severity exacerbated by higher SO2 concentrations, which are typical in white wines compared to reds.
Merely increasing the thickness of the plastic liner was deemed an imperfect solution due to elevated manufacturing costs and waste. Instead, researchers proposed utilizing a more robust liner formulation combined with a lower concentration of SO2 than traditional winemaking practices typically allow. Unlike bottles, cans offer the advantage of hermetic sealing, which helps mitigate the heightened oxidation risk associated with lower SO2 concentrations. This approach is anticipated to extend the shelf life of canned wine to at least eight months.
The findings, published in the referenced research, not only address a specific scientific problem but also underscore the fascinating intricacies of aluminum beverage cans. The study provides valuable insights into tackling such challenges and highlights the remarkable versatility of this humble packaging material.
