What is light-struck damage (skunking) and how can it be prevented?

• A. Light-struck damage is caused by darkness harming flavors.
• B. Light exposure increases malt sweetness.
• C. Light exposure, especially UV, causes a reaction with hop aromas forming a skunky smell; prevent by using dark bottles and protective packaging or storing in dark areas.
• D. Light exposure has no impact on beer.

Answer: (C)

Light-struck damage happens when beer is exposed to light, especially ultraviolet light, which triggers a photochemical reaction with hop-derived compounds. This reaction forms a sulfur-containing compound that gives off a skunky aroma, so even brief light exposure can ruin the beer’s aroma and flavor. The way to prevent it is to keep beer out of light and use packaging that blocks UV light—amber or brown bottles or cans—or store beer in dark, shaded areas. This keeps the hops’ compounds from reacting and preserves the beer’s intended aroma and taste.