Stay away from clear/green bottles!:

"When your beer really stinks

Dec. 21, 2000

Few beer tasting terms are more descriptive or straightforward than "skunky." Quite simply, a skunky beer emits an aroma it didn't have when it left the brewery.

The smell is the product of the chemical reaction that takes place in the bottle when bright light strikes the hops, creating what's technically known as "light struck" beer. The reaction is stronger with paler and hoppier beers. The resulting chemical is identical to that in a skunk's defense system, and light-struck beer puts off one of the most powerful aromas around.

Green and clear bottles do little to protect a beer from skunking, and while dark brown bottles are much better they are far from perfect. Because many of the best known imports come in clear or green bottles consumers have come to associate a skunky aroma with imported, often more expensive beer. That doesn't mean their brewers intended them to taste that way.

The brighter the light and the longer bottles sit in that light the stronger the skunky smell will be. Even dark brown bottles won't guard a beer from the bright fluorescent lights popular in grocery stores and many other beer retail outlets for very long.

You don't have to settle for that beer. In some stores you'll see six-packs sitting on tops of cases. Don't grab that one, but get your beer from inside the case. A sealed case is even better. If you want beer from the cooler don't be shy about asking if there are unopened cases in the cooler and buying a six-pack from one of those.

Buying beer that has been kept out of the light gives you a better chance of getting a "skunk free" beer. It's up to you to keep it that way -- mostly by continuing to keep it out of direct light -- until you drink it."