One of the ways you know you're crossed the line from plain old "beer drinker" to "beer geek/beer connoisseur" is when you start buying beer not just to drink immediately or in the near future, but also beer to save. That's called cellaring, from the days when most beer was actually stored in cellars.
The vast majority of beers are made to be drunk as soon as possible. A Budweiser is as good (?) as it's ever going to get the instant it leaves the brewery; it's all down hill from there. Hence their emphasis on the "born on" or "best before" dates. Light, heat, oxygen... they're all enemies of good beer, leading to chemical reactions that produce the dreaded stale or skunked beer. So why in the world would you buck common sense and deliberately age a beer?
Well, because certain kinds of beer actually benefit from aging. What kinds of beer are likely to benefit from a few months to a few years in the cellar? First and foremost, they must be bottle-conditioned, that is beers that still contain live yeast. A pasteurized or chill-filtered beer (about 90+% of American beer) will not improve with aging because there is no living yeast in it. Biologically inert, it can not grow; it can only decay. Second, beers suitable for cellaring are typically 7+% Alcohol By Volume; there are exceptions to this, like certain sour beers, but it's a good rule of thumb. Alcohol acts a a preservative and 7% or so seems to be the amount needed for enough long-term stability. Also, beers which have been dosed with Brettanomyces, a notoriously slow working yeast, often benefit from giving it plenty of time to do its work. Finally, if the brewer bothered to give the brew a vintage date, like Sierra Nevada 2009 Bigfoot Ale or Alaskan 2008 Smoked Porter, that's a pretty dead giveaway that he or she expects you to at least consider cellaring it.
If you decide you're going to come over to the geek side and start cellaring beer, what do you need to do it? Well, pretty much all you need is a cool, dark place in which to store your beer. By cool, I mean 55-65 F, with hopefully little to no temperature variations, though I've heard that somewhat higher temps during the summer don't seem to cause any problems. If you've got a cellar or basement that meets those criteria, you're good to go. Just put up some shelves and start buying beer. Myself, I lack a basement in my home, so I use a combination of a bedroom closet and a special wine cooler-type refrigerator that I had regular glass shelves made for. The reason for those shelves is that beer is always stored upright during cellaring, not on its side like wine. If you're really ambitious, you'll have a cellar "book"; this is just a notebook or some other place where you check brews "in" when you add them to your cellar and then "out" when you decide to drink one. If you've got a huge cellar, a book helps make sure you don't "lose" something amongst all your other treasures.
I went into my cellar this weekend and pulled out a little jewel that has been aging for about a year and a half. It's a 22 oz bottle of Midnight Sun's Lust, the last of their 7 Deadly Sins series. It's easy to see why I decided to put one away for a bit: Bottle conditioned, 11.5% ABVs, and dosed with brett; Lust practically screams to be cellared. The impetus for this expedition into the back of my cellar was being offered a taste of an in-progress beer on Friday, 7/17, at St. Elias by Zach Henry. He'd added some sour cherries to one of the strong, dark beers that he's aging in used bourbon barrels. I thought it was pretty darn good, but I couldn't help thinking it was reminding me of another beer that I'd had before. It took a bit, but the memory finally dropped in, and sent me cellar-diving for my last bottle of Lust.
I took it over to the brewpub this weekend, looking to share it with Zach, only to learn that he and his wife Jenny were in Seattle with their 6-year-old daughter, who is having very serious medical problems. So that beer tasting is on hold now, awaiting Zach's return, and best wishes to his daughter for a speedy and complete recovery.
So pick up a couple of strong brews, put 'em in a cool, dark place, and join the fun.
Until Next Time, Cheers!