two-part series at All About Beer on staling. Some folks pointed out that a few styles do age well and some improve. I did acknowledge that in the second post, and it's definitely something worth noting. The problem is that this truth seems to have overwhelmed the far bigger truth that most beers don't improve with age. Worse, the focus on the beers that do improve creates a subtle sense that age is good for beer, and this is definitely not true. I'm pretty certain that many fans are not aware of how perishable beer is nor do they recognize that a "bad" beer is actually just stale. (If you spend any time reading the ratings sites about your favorite beers, you can identify the many times this happens.) It is definitely true that some beers age. But they are the extreme minority, and if that's the one fact you know about beer and time, you have learned the wrong fact.
Staleness is not identical to oxidation. Long before you get those flavors of paper or wet cardboard, you get dullness; the intentional flavors placed in the beer leech out. These are the flavors we love in most of the styles we drink: delicate, bready malt flavors, vivid, green hop aromas and flavors. As a beer stales, those delicate notes are the first to go. Whereas in those beers that do age well, new flavors emerge as old ones fade, in most beers the process is one of subtraction. Arguing that this is good for beer is like arguing that bread tastes better once you leave it on the counter for a week.
Modern IPAs, which owe so much of their character to post-kettle hopping, are especially vulnerable. (Since they are the most popular styles among beer geeks, this fact is muy important.) But it happens in just about all the beers most people drink--light lagers, all of the light ales of Britain, most of the lagers in Germany and the Czech Republic, and even many Belgian ales. More than 99% of the world's beers fall into this category. (Because Belgian ales almost invariably go through bottle-conditioning, oxygen is scrubbed from the bottle and those beers age a lot better than most. Belgian ales also have fewer hops--and almost never late-addition hops--and usually have higher alcohol, two other advantages.)
I don't consider myself an expert on beer but I am a pretty reliable emissary from the brewing world. I've talked to hundreds of brewers in several countries. Except for the lambic brewers (who produce, collectively, something on the order of less than 50,000 barrels a year) I have not encountered a single one who argued that their beer should be drunk stale. Rather, they talked extensively about the processes they use to keep their beer fresh. I don't doubt that there are people out there who like stale beer, but it's akin to liking lightstruck beer. (There's no arguing about taste!) Except in the case of a few types of beer (either high ABV or wild, usually dark), the flavors are closest to what the brewer intended when the beer is freshest. Don't believe me, believe the brewers.
If this all seems outlandish, you can actually run your own experiment. Select an IPA you admire with a lot of perfumy scents and rich hop flavors, buy a bottle, and put it in a warm cupboard. Wait three months, and then buy a fresh bottle and do a blind tasting of the two. This experiment also works with English bitter, session lagers, pale ales, wheat beers, German ales, light Belgian ales--pretty much anything that's not strong or wild.