Storing beer away from light helps to prevent which of the following flavors?

Storing beer away from light is crucial in preventing the flavor commonly described as "skunk." This off-flavor occurs when certain types of beer, especially those in clear or green bottles, are exposed to ultraviolet (UV) light. The light interacts with the hops in the beer, leading to a chemical reaction that produces 3-methyl-2-butene-1-thiol (MBT), the compound responsible for the skunky aroma and taste. By keeping beer in a dark or opaque setting, the preservation of its intended flavor profile is ensured, free from this undesirable skunked characteristic.

The other flavors listed — butter, paper, and vinegar — result from different causes. Butter flavors are typically linked to diacetyl, paper flavors stem from oxidation, and vinegar flavors are a result of acetic acid formation — none of which are directly related to light exposure.