On a recent visit to my in-laws, I absent-mindedly grabbed a can of beer from their secondary fridge, used mostly to store beer and other drinks. As I began drinking the Sam Adams Boston Lager, I was surprised to find it tasted completely different than I remembered. Instead of the pleasantly flavored lager, I was sipping something that was lifeless, bitter, cardboard-like and just … bad.
Samuel Adams is not a brewery I’d consider prone to quality problems, so I started to look for another cause. Thankfully, I didn’t have to go much farther than the bottom of the can. Printed there was a date of May 2014. Yikes!
Unlike wine, most beer does not improve with age. In fact, the primary ingredient that makes beer distinct from other beverages – the hops – tend to suffer most at the hands of time. Researchers have discovered several reasons why. The bitter-flavored compounds found in hops taste great at first, but then can break down into smaller components, producing harsh or unpleasant flavors where hops used to be. This type of breakdown is worsened by higher temperatures, so the long-term room temperature storage of beer is a recipe for a shortened beer life.
Another culprit is surprisingly difficult to dodge because it is ubiquitous: oxygen. Whenever beer is packaged, it comes into contact with at least a little oxygen. Being the aggressive molecule that it is, over time, this oxygen will degrade both the alcohol and other aromatic compounds and flavors, leaving behind a taste that is often described as “wet cardboard.”
To me, this always comes across as sad, as if the poor beer has just had all of the life sucked out of it. While brewers do whatever possible to minimize the beer’s contact with oxygen during filling and bottling, over time, even the smallest amount will start to have an effect. This can be a particular problem depending on the methods used for growler filling; if the growler itself isn’t filled with carbon dioxide first, the process of filling into such a large container can wreck a beer pretty quickly.
To help beer drinkers find the freshest beer, some breweries are beginning to label their beers with either “best by” or “bottled on” dates. Larger breweries with quality control programs do extensive testing to determine the average shelf life of their beer, and the window in which it tastes its best. Some have gone so far as to put warnings on their labels, and Stone Brewing Co. in California has named an entire series of beer “Enjoy By ___” followed by the date that it’s past its freshness.
Now, before the beer geeks out there get cross with me, there are definitely exceptions when it comes to aging beer. Brews with more alcohol, such as barleywines, imperial stouts or Belgian quads can be aged for years. Sour and wild-fermented beers can also change in complex and unexpected ways over time, which is why many of the beers at Allagash are aged for years and blended together. It isn’t that the beer in these cases remains unchanged, but instead, it slowly matures and develops new flavors.
So how old is too old? As a general rule, most beers are good for up to four months, if you’ve kept them chilled and away from light. However, that guideline may be far too long for the newly-popular so-called New England IPAs, the juicy/hazy styles. These beers are brewed in a different manner and are also often dry-hopped, meaning that there are hops added after brewing. Lots of dry-hopping can lead to precipitation, where some flavor compounds fall out of solution and start to build up at the bottom of the beer. For the haziest beers, this can start to happen only a few weeks after packaging. For these beers, I’d encourage you to drink them soon, and after a month, you may need to start to significantly lower your expectations on flavor.
Thankfully, most of Maine’s breweries that are canning these hazy hop-bombs have taken to date labeling. It is usually found on the very bottom of the can. Depending on the brewery, there can also be silly or cheeky messages added. Many are inside jokes, but some show a bit of the brewery’s character. On a canning day that happened to fall on the birthday of Dirigo Brewing Co. owner Tom Bull, the date labels were accompanied by “Happy Birthday Tom!” These messages are both internal and also put there to encourage you, the consumer, to check the date.
Adding this information to the label can help brewers avoid being judged on a can or bottle that’s months (or, in my case, years) past its prime. Thankfully, unlike other food products, expired beer will never make you ill (as long as proper sanitation was observed), so the worst-case scenario is a matter of disappointment and taste, rather than health. You probably do not need trash all the beer that is a day beyond its “best by” date, but I heartily recommend that you think twice before opening a lager that’s been in the back of the fridge for a few years.