What is a major enemy of beer that accelerates oxidation when stored?

High temperatures are a significant enemy of beer as they can accelerate oxidation, leading to detrimental changes in flavor and aroma. When beer is stored at elevated temperatures, the chemical reactions that cause oxidation occur more rapidly. This can result in off-flavors such as cardboard or sherry-like notes, which are undesirable characteristics for most beer styles.

In addition, high temperatures can negatively impact the stability of the beer, leading to potential spoilage and degradation of both the ingredients and the brewing process. As a general rule, beer should be stored in a cool, dark place to maintain its quality and freshness, highlighting the importance of temperature control in beer storage.

While the other choices may influence beer quality in different ways, they do not directly accelerate oxidation to the degree that high temperatures do. Low humidity can affect the cork seals on certain bottles, low light can lead to skunky flavors in light-sensitive beers, and carbon dioxide, albeit important for maintaining carbonation, does not impact oxidation like high temperatures do.