What It Means If Your Beer Is 'Lightstruck'

When a beer is described as "lightstruck," it refers to a condition where the beer has been exposed to light, particularly ultraviolet (UV) rays, causing a chemical reaction that affects its flavor. This reaction primarily occurs in beers that are packaged in clear or green bottles, as these do not effectively block UV light. When UV light penetrates the bottle, it reacts with the hops present in beer, leading to the production of unpleasant compounds such as 3-methyl-2-butene-1-thiol (MBT). This compound is responsible for the skunky or off-flavors often associated with lightstruck beer. The term "skunky" is used because the aroma is reminiscent of the smell of a skunk's spray. The lightstruck effect can occur relatively quickly, sometimes in just a few minutes of direct light exposure, especially under intense lighting conditions. To prevent this, brewers often use brown or amber bottles, which provide better protection against UV rays. Additionally, storing beer in dark, cool places and using cans instead of bottles can help preserve its intended flavor profile. Being aware of lightstruck beer is essential for both brewers and consumers who wish to maintain the quality and taste of their beer.