What's the shelf life of beer?

It probably won't be tasty (beer does not get better with age-- one of the advantages of homebrewing), but as long as it doesn't smell bad or excessively fizzy, it should be okay.

You've had beer in the fridge for several years!?!?! ...the tragedy is overwhelming. My recommendation is to drop them off with some college students, and just don't tell them it's that old. they won't care, and i doubt it'll kill them. ;-) that way it doesn't have to go to waste! Yay environment!

Apologies to all beer drinkers (that would be most of the population, I guess). But in spite of Evan's heartfelt plea, I have decided to use my aged beer to catch slugs. That is also good for the environment, or at least, my garden.

It depends on the type of beer. The darker the beer, the longer it will last; a stout will last for years.

Well my local pub gardener dug up a bottle in the beer garden rusty cap and all, and guess what it tasted beautiful

I’d use it to wash my hair

http://www.wisebread.com/21-great-uses-for-beer

It depends on a lot of factors. The strength (or amount of alcohol in the beer) will be a big factor. The more alcohol, the more likely it is to age well. 8% abv+ is usually a good starting point for aging. If it’s been in the refrigerator this will help slow the aging process. Beers this strong can last quite a while. I have some beers that are around 10% abv + that are approaching 5 years old and are great. Normal run of the mill beer should be fine for a year or so, but will definitely not be as good as fresh.

Don’t worry, though, nothing can grow in beer that can hurt you. The worst case scenario is that it won’t taste great.

Hoppy beers will lose a lot of hop flavor in a year. Smaller beers (under 8% abv) will not last as well, but will still be drinkable several years later.

This is all negated if the beer is “infected,” but this is a quality control issue with the brewer, not an intrinsic event that will definitely happen to beer.

The color of the beer doesn’t matter. There are a lot of dark beers (i.e. stouts) that are quite dark and low in alcohol (such as Guinness, which is a little over 4% abv) that won’t stand up to aging. The biggest determining factor is the amount of alcohol. Also sour beers (those that are meant to be sour such as Belgian gueuze) will last for decades possibly.