The idea of selling wine in cans is not new. In fact, the industry first attempted it 90 years ago, and since then it has tried to solve its most important challenges. One of them is the rotten egg smell that affects many brands, and after a long list of hypotheses, a team of researchers from the Department of Food Science at Cornell University finally hit the mark...
History tells us that American wineries tried to commercialize canned wine in 1936, seeking to repeat the success achieved by beer the previous year. However, wine proved to be a much more unstable and sensitive product to the variables of its packaging. Aluminum cans had to travel a long road to become the engineering marvel they are today, but their modern alliance with wine is full of imperfections. The most important? The rotten egg smell.
Why does canned wine smell like rotten eggs?
Professor Gavin Sacks from the Department of Food Science at Cornell University was contacted by wineries some years ago, who explained their difficulties when canning wine: leaks, corrosion, and rotten eggs. Despite following all the recommendations of can manufacturers, the wine always showed resistance. The strategy was to identify the responsible components and determine why it only happens with wines (Coca-Cola has been in aluminum cans for decades, and no incident of this type has ever been recorded...).
Professor Julie Goddard joined the research, bringing her experience in materials science and packaging. The process was slow, taking months to evaluate the condition of some samples, while others were "accelerated" in more hostile environments. In all cases they reached the same conclusion: Sulfur dioxide (SO2), used by wineries as an antioxidant and antimicrobial, can pass through the inner plastic layer in cans and interact with aluminum. This produces hydrogen sulfide (H2S), well known for its rotten smell (I have had experiences in the past, and you do NOT want that smell in your home).
Wineries use between 0.5 and 1 part per million, but the study suggests that any value above 0.5 increases the presence of hydrogen sulfide and the rotten egg smell after 4-8 months of storage. Wineries should aim for the lowest threshold, but that forces them into a balancing act, as it would (slightly) increase the risk of oxidation. Increasing the thickness of the inner layer is not a magical solution either, since the interaction with the liquid does not disappear, the can becomes more expensive, and it loses some points environmentally (that plastic is burned when recycling aluminum).
What's next? Advancing the search for alternative protectors and optimizing the link between production and canning so that the rotten smell in wine finally becomes a thing of the past.
Access the study: Click here
Source: Phys.org
