Two weeks ago, I attended Cambridge Brewing Company's Barleywine Festival, where I got to drink several Barleywines from 2005 to 2010, each vintage aged in a different barrel. On my 22nd birthday last Tuesday, I enjoyed a Brooklyn Monster Ale Barleywine from 2009 that I had let sit in the cellar of my house for over a year. In both of these cases, I got to enjoy one of the most interesting aspects of beer: cellaring and aging.I am not a fermentation scientist, but in a beer there are numerous organic compounds, among them diacetyl, esters and the alcohol itself. All of these gain improved flavor when they are allowed more and more time to mature. The alcohol fades, and other compounds are enhanced by time. The result is a more developed, flavorful drink with significantly less booziness.

This works great for imperial stouts, barley wines, Belgian quads and other high-alcohol beers. It should be said that not all beverages get better over time; there needs to be enough alcohol to act as a preservative. Most beers have a shelf life. Lower alcohol beers will spoil over time and should be drunk within a year or so. You should never age a very hoppy beer. Hops are quite volatile and will fade in a beer quickly, especially in hop-bombed double India Pale Ales. Therefore, you should drink these quickly.

Aged beers demonstrate a lot of change in their flavor profiles. A perfect example of this is the Brooklyn Monster Ale. A year ago when I had this beer, it was a boozy mess. It was hot, the alcohol overpowered everything, and the sugars made the drink very thick and syrupy. One year later, that syrupy nature was gone, and I was treated to a drinkable high-alcohol beverage with great dark fruit and biscuit notes. I think another year or two would only make this beer even better.

Beer can mature in bottles, as well as in other containers. A new aspect of the American beer tradition is the idea of maturing beer in wooden barrels previously used for aging liquor. The result is that the beer gains new characteristics not attainable in the standard brewing process, such as notes of wood and those of the alcohol previously stored in the barrel.

One of the places where this could be found was at the Cambridge Barleywine Festival: Nearly all of their Barleywines had been matured for a few years in barrels. Their most recent one was aged in rye whiskey barrels. Other barrels included those that originally stored port, bourbon and chardonnay. Each barrel revealed different flavors and brought out different notes in all of the beers, which were otherwise from the same recipe.

The final barleywine I tried was a 2005 vintage that was not aged in any barrel. After 6 years of aging, this brew had produced an incredibly clean malty and fruity taste. I'm glad that, in the end, they kept the earliest vintage out of the barrel to develop what the beer actually should taste like.

In conclusion, beer aging is a wonderful technique to improve high-alcohol beers. It's very easy to try on your own. Just find a cool, dark place in your house and leave the beer upright for an extended period. The cap can produce strange flavors, however, so be sure that the beer never touches it.

Next week, I'm going to focus on the polar opposite of aging beers: session beers.