The Scientific Reason Canned Wine Can Smell Like Rotten Eggs

Canned wine sometimes emits an unpleasant smell reminiscent of rotten eggs due to the presence of sulfur compounds. These compounds, such as hydrogen sulfide, can develop during the winemaking process or as a result of chemical reactions once the wine is sealed in a can. The use of sulfur dioxide is common in winemaking as a preservative to prevent oxidation and microbial spoilage. However, under certain conditions, sulfur dioxide can be reduced to form hydrogen sulfide, particularly in the absence of oxygen and in the presence of certain yeast strains or residual amino acids. The canning process itself can exacerbate this issue. Cans provide an airtight seal that limits oxygen exposure more than traditional glass bottles. While this is beneficial for preserving the wine, it also creates an environment where sulfur compounds can manifest more noticeably. The lack of oxygen prevents these compounds from volatilizing or breaking down, allowing the rotten egg aroma to become more prominent when the can is opened. Winemakers are exploring various methods to mitigate this issue, such as adjusting sulfur dioxide levels, refining canning procedures, and experimenting with additives that can bind or neutralize sulfur compounds.