The answer to the question 'Does beer expire?' is yes, but it's not as simple as that. Beer can start to taste unattractive or flat when it has expired, but it won't become unsafe to drink. The shelf life of beer depends on the type of beer, how it is stored, and whether it has been opened or not. Bottled beer stored in a dark and cold area, such as a fridge, can last up to 6 months.
If stored hot, bottled beer can spoil in as little as 3 months. Cans provide the best protection against oxygen and light, and can last up to 6 months if stored cold and 3 months if stored hot. If you buy a commercial keg and use a party pump to serve, the beer will only last 12-24 hours once it has been touched. Unopened bottles or cans of beer can last up to two or three years in the refrigerator.
However, an open bottle or can will usually only do for a day before oxidation destroys all good flavors. If you put open beers back in the fridge, it may be worth looking into resealable containers like growlers or even a keg. Beer is just like any other food; it is made from all-natural plant raw materials that decompose naturally over time. Most types will keep the best quality for six months at room temperature, but you can keep them for up to a year in the fridge.
There is an “expiration date” marked on the bottle or can, but that is more of a guide than a law. At best, you will experience a slight upset stomach after consuming expired pasteurized beer. Beer can become skunk when exposed to the right combination of UV rays and colored glass that doesn't block rays. Place the lidded cans and bottles in the refrigerator because they help achieve the ideal temperature and the best UV protection for a delicious beer. Do not mix this with the intentional exposure to sunlight that some manufacturers do to get a particularly recognizable beer flavor. Many bars, breweries and breweries fill growlers and crowlers directly from their taps so you can enjoy fresh beer from the comfort of your home.
Beer is a fermented drink that has great protection against harmful pathogens due to low pH and alcohol. Brewers work to make beer last as long as possible, and the alcohol content, low pH of beer, and antimicrobial activity of hops have some significant advantages.