Does Beer Go Bad? Here’s How You Can Tell

1. It smells like a skunk

This should be pretty obvious since skunk isn't exactly an appetizing scent, but a skunky beer is often not a good beer. This is actually the root of the term "skunked," which many people use to describe bad beer. Basically a beer gets skunky when it's exposed to the right combo of UV rays and colored glass that doesn't block out the rays.

Some beers, like Heineken, are bottled in colored bottles and therefore often get skunky, which people tend to enjoy. Therefore, skunky beer is sometimes not indicative of a bad beer, which is pretty damn confusing.

2. It tastes stale

Until you open it, your beer shouldn't have come into contact with any oxygen. Early contact with oxygen is called oxidation and it results in a stale, cardboard-like taste. This is why the Natty Light you drink at frat parties tastes even more bland than usual. A keg left tapped for too long is a surefire way to oxidize your beer.

3. It tastes like popcorn

Unless you're drinking a funky craft brew that's supposed to taste like a movie theater snack, your beer should not taste like popcorn. Diacetyl is a buttery-flavored compound that's produced in almost every beer fermentation.

Exposure to too much diacetyl is actually very dangerous for your lungs, but luckily the amount of the flavoring in beer is not near that level. Still, it's not something you want tons of in your beer.

4. It has a weird taste (like cabbage or sewage)

Despite the fact that there are tons of weird beer flavors out there, it should be pretty clear if the flavor you're tasting is not intentional. Some common flavors that can indicate a bad beer are cooked cabbage, sewage, sulphur, or just an abnormally sour taste.