By Chris Morris
Dogfish Head founder and owner Sam Calagione once said that the best way to age a beer is to take the bottle and put it in a box. Then, go out into your backyard and dig a hole a few feet deep. Put the box in the hole, cover it up, and wait. Not only will the bottom of that hole be dark (light speeds up oxidation in beer, which produces that much-hated "skunked" flavor) and close to cellar temperature, but you'll be less likely to go and drink that beer on a whim - it's like built-in patience.

Of course, you don't really have to dig a five-foot hole in your backyard to age a beer properly. Aging beer is a science, but we don't all need to be Marie Curie to age a beer well. Here are a few helpful tips.
1. Probably the most important thing in aging beer is realizing what types of beer age well and what types don't. First, let me say this: professionally produced beer won't spoil. There may be a "best by" date, but there's no harm in aging anything and everything. That being said, not all beer will age well.
All beer will change with time. Yeast and the other microorganisms in your beer are living creatures - as time goes by, they will produce different biproducts that will change the flavor of the beer, for better or for worse.
A good general rule is that high-alcohol beers age well. The high alcohol content means two things. First, the large amounts of alcohol will protect the beer, killing off many of the bad flavors associated with a bad beer. Second, the high alcohol is (usually) the result of a large amount of base grain (more base means more fermentable sugars which means more alcohol) and these malty flavors often age well (I say high alcohol "usually" results from more base grain because this is generally the case with **cough** real **cough** beer; the commercial breweries of the world are known for adding in extra sugar to increase the alcohol content of the beer without adding any body to it, keeping it light and tasteless).
A good rule of thumb is that 10% ABV and higher will age well.
Also important is knowing what beers won't age well. Some ingredients are better fresh. Take IPAs, for example. The defining characteristic of an IPA is the intense hop flavor. Because hops are better fresh, IPAs aren't good candidates for aging (an exception to this rule is very high ABV IPAs, like Dogfish Head 120 Minute, which clocks in around 20% ABV. These are often already aged before they're even bottled, and will continue to get better with time).

2. How you actually go about aging your beer is also crucial. Having a beer that will age well is one thing, aging it correctly is another. There are two variables to keep in mind here - light and temperature. Light and heat both speed up oxidation in beer, which is essentially what ruins it. So you want to keep your beer in a dark place at cold temperatures, around 50 degress. A refrigerator will do just fine, but again, be careful with the light. I suggest wrapping each bottle in one or two of those brown bags you pack your kids' lunches in. Tape it shut and stick it in the bottom drawer, then forget about it for a few years.
Another good idea is to try to store bottles upright. If you keep them on their sides, sediment will fall to the bottom of the bottle, which is now really the side. When you pour it months or years later, that sediment will come out with the pour. So try your best to keep them upright. If you can't, then take them out a few hours before you're ready to drink them. Roll them around a little bit, shake them lightly, and put them in the fridge, this time upright, for a few hours before enjoying.

3. Experiment. If you don't know if a beer is a good candidate for aging, there's only one way to find out (other than using the almighty Google). Put a few away. Try one in a few months, then another in a year. If it seems to be going well, wait another year before trying the next one. If it isn't going well, drink them all right then and there. Every beer will change with time, you just need to find out if its for better or worse.

I currently have a 4-pack of eight-month-old Dogfish Head Burton Baton and 5 two-month-old 120 Minute IPAs in the bottom drawer of my fridge. Anyone have anything interesting in theirs?
Chris Morris runs his own beer blog Black Dog Brewhouse where he discusses everything beer. Follow him on Twitter @ChrisMorrisBeer