Most people are unaware that beer can be aged for a considerable amount of time like fine wine. Your typical beer has a shelf life of roughly 3 to 6 months, but there are certain styles that can be aged for a couple of years and up to half a century, if not longer. Aging beer can have different effects for different beers. Some beers mellow, some gain complexities, some become more intense (specifically sour beers), some suffer from oxidation (or a wet cardboard off-flavor) and others have their flavor completely go away. Although you can find reviews of some aged beers online, the only way to determine for sure what the beer will taste like with a couple of years of age is to actually try it.
While predicting if a beer benefits from age or not contains a lot of guesswork, there are some styles of beer that do better with age than others. The biggest factor to finding a candidate for aging is alcohol content. Since alcohol protects the beer and is a signal for intense, complex beers, the more alcohol in the beer the better candidate it is for aging. If the beer is approaching 10 percent alcohol by volume (abv), it should be fine for aging. There are two cases that do not follow this rule of thumb, however. Some Imperial IPAs or other beers that have a high abv but rely on hops for flavor do not age well, as the hop flavor fades quickly and you are left with a fairly boring, malty beer. The other exception, are sours or wild ales. These beers may be less than five percent abv, but due to the bacteria or wild yeast can age with the best of them, they typically becoming a drier, more intense sour flavor.
Once you determine which beers you want to age, the next step is determine where to age the beers. The two biggest factors are light and temperature. The beer should be kept in complete darkness, as light can skunk beer. The ideal temperature should be a constant 50-55 degrees. A colder temperature and the beer will take longer to age; warmer and it will age faster, with a potential for off-flavors. Unlike wine, beer should be stored standing up to allow the yeast to settle to the bottom.
One of the best beers to age is Sierra Nevada Bigfoot Barleywine (9.6 percent abv), as it is fairly easy to find and not overly expensive. There have been people who have sampled Bigfoot from the past 10-15 years and noted some impressive changes in the beer. Since I have only been drinking beer for a little over a year, I only have the last two years to taste, but still could notice a significant change in the beer. Both beers (2011 and 2010) were perfectly clear, dark red with a tan head. The 2011 smelled like sweet malt, citrus and other fruits, with just a hint of alcohol. The 2010 was significantly less hoppy, but had the same fruit (specifically orange) and aroma, but also had some caramel and even a hint of chocolate flavors. The fresh 2010 was drinkable for a beer nearly 10 percent but still had significant hop bitterness and a lot of sweet malt.The two flavors did not seem to blend that well together. The aged 2010 was even more drinkable; smooth sweet malt mixed with orange and caramel mixed in. There were even hints of cherry. Overall I enjoyed the 2011, but the 2010 was far superior. It was significantly smoother, more drinkable, had a much larger caramel presence and was more complex on a whole.