Here's the deal on skunked beer from an article I wrote...
"First and foremost, beer does not go “skunky” by temperature change. It’s time we busted the myth of beer spoiling by going from warm to cold to warm again. I’ve talked to literally hundreds of people in retail stores who told me they didn’t want to buy their beer cold because they had a long drive home, or didn’t have room in their refrigerator to keep it. This usually led them to purchase some kind of boring, grocery-store beer from a big, multinational brewing conglomerate. If I was successful in my argument, they put down the bland alcohol-water and bought some good craft beer from the cooler, because what I told them made perfect sense: the only way a beer is going to spoil by temperature change is by EXTREME temperature changes.
I told these knowledge-thirsty beer consumers that if they were planning on freezing their beer, then putting it on the stove, then dropping it in liquid nitrogen, then laying it out on an asphalt basketball court at High Noon on the equator, then the beer would most certainly spoil. Temperature changes of a few dozen degrees would have no noticeable effect on the liquid, as long as it was consumed in a reasonable matter of time. Obviously, this was a very extreme example to hit my point home, but the point was hit, regardless.
Time and time again, the term they loved to throw around was “skunky.” Temperature shock will not “skunk” your beer. Extreme temperature changes will really screw with the perfect chemical balance of a bottle of good beer, or crappy beer too, for that matter. The most common problem with these beers is oxidation, which is evident by a papery, wet cardboard flavor/aroma. Chew on a piece of looseleaf paper like you’re hiding Government Secrets, then you’ll see what I mean.
That “skunky” beer in your hand is actually lightstruck.
Lightstruck is exactly what it sounds like: the beer was damaged by light, particularly sunlight, or fluorescent lighting like that of liquor stores and beer warehouses. When UV rays penetrate (insert laugh here) the glass of a beer bottle, they manipulate the chemical makeup of iso-alpha acids produced by the hops, our delicious floral friends that give beer its bitterness. The result of this unwelcome penetration and manipulation is the creation of a new compound called methyl mercaptan, one of the many components found in the defense mechanism of: you guessed it, the skunk. Kinda makes sense now, as to why it’s referred to as “skunky.”
Most beer doesn’t have this flavor or smell because most beer is packaged in brown glass bottles, which are over 98% resistant to UV rays. Guess which color glass lets that light in. Time’s up: green and clear bottles. This is the reason certain beers from South of the Border are served with a lime wedge; it’s more than vacation in a bottle, it’s a cover-up method. If your garbage disposal stinks, you may pour some citrus-scented dishsoap down there. The stench doesn’t go away, but the wife and kids won’t notice it right away.
This is where some people are going to get really defensive. Those green glass bottles from Europe that contain the really fancy and expensive beer… you know, the ones you bought in college when you wanted to show some girl you really had class? That interesting aroma and flavor is not a unique trademark of that brand, or any of those brands that package that way. It’s an indication that beer has been spoiled as a result of UV light. I’m not saying it’s bad. You may like it. You may be drinking one now, but you deserve to know the truth. Don’t believe me? Try it in cans or on tap; totally different brew!
You know the real ***** of the matter? It doesn’t take long for light to damage beer. On the off chance that beer in green or clear bottles is not already damaged when you leave the store, less than one minute in the sun will spoil it. That’s roughly the time it takes to walk to your car with your new investment. The only real way to avoid this problem is to Drink Better Beer. Buy beer in brown glass bottles that has been kept away from light as much as possible. Beer is liquid bread; and like its non-liquid counterpart, it can go bad. The one true saving grace is this: there are no harmful bacteria on earth that can live in alcohol. That being said, your green-glass grocery-store special may taste like the business end of a skunk, but it won’t kill you."
10+ yrs in the beer business... Lifelong Beer Advocate...
Drink Better Beer!