I don’t know what I was on last week when I wrote my mini-review of Pilsner Urquell. For some reason I used the word “Diacetyl” referring to the skunky nature of the beer.
Diacetyl is a buttery aroma and flavor that is a natural yeast by product. Though it would be inappropriate for a Boh. Pils, it is acceptable and often desirable in other types of beer.
Light-struck or “skunky” is a, well, skunky aroma that results when fermented beer is exposed to light (as often happens when packaged in clear or green bottles). Supposedly some manufacturers WANT a bit of skunk on their beer and have therefore resisted using brown bottles. Or maybe appearance is more important than quality. Who knows.
An list of all recognized beer faults is provided by (who else?) the BJCP here.
Anyway, Diacetyl ≠ Light-Struck and the offending error has been deleted from last week’s post.