Beer may become 'skunked' when:

Beer may become 'skunked' when:

• A. It is exposed to light for a prolonged period of time
• B. It is stored at cold temperature
• C. It is poured into a clear glass
• D. It is pasteurized

Answer: (A)

Exposure to light, especially UV light, triggers a photochemical reaction of hop-derived compounds in beer, turning iso-alpha acids into volatile sulfur-containing compounds that smell distinctly skunky. This is why beer in brown bottles lasts longer: the bottle blocks much of the light. Clear or green bottles let more light through, accelerating skunking. Temperature slows the reaction but doesn’t prevent it if light is present, so cold storage helps only by slowing the process. Pasteurization doesn’t create the skunky aroma, and pouring into a clear glass increases light exposure, reinforcing the same idea that light is the trigger.

Exposure to light, especially UV light, triggers a photochemical reaction of hop-derived compounds in beer, turning iso-alpha acids into volatile sulfur-containing compounds that smell distinctly skunky. This is why beer in brown bottles lasts longer: the bottle blocks much of the light. Clear or green bottles let more light through, accelerating skunking. Temperature slows the reaction but doesn’t prevent it if light is present, so cold storage helps only by slowing the process. Pasteurization doesn’t create the skunky aroma, and pouring into a clear glass increases light exposure, reinforcing the same idea that light is the trigger.