Beer Exposure to Sunlight

Hops + Sunlight = Skunky

If you have ever tasted a skunky beer you might think to yourself, after spitting it out, what could possibly cause an off flavor that bad?  Well one reason for this flavor would be that the beer was exposed to sunshine (ultraviolet radiation). Specifically, sunlight initiates degradation of the alpha acids into smaller chains which then allow sulfer to happily bond to form 3-methyl-2-butene-1-thiol, if you care!  This is what tastes like a skunk or rotten eggs, something not preferred in my beer.

This is why beer bottles are amber in color as it does a better job at blocking UV than would a clear bottle.  With time though, UV will impact the flavor of an amber bottle so it is not completely safe.

If you want to experience the flavor for yourself take a moderately hopped beer and place it into direct sunlight in the middle of summer when UV is strongest.  Take samples over a time period of an hour and notice the degradation in the flavor, that is if you can let a beer sit that long!  Skunk – yum…..

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