Old Beer is Stale Beer
Jack Carson

Like bread, cookies, and watching the same movie, beer can get stale.  The
shelf life of beer is generally defined as to how long that beer will stay fresh in
average conditions. Unlike food expiration dates, drinking a beer past the
“best by” date isn't dangerous, but why drink bad beer?

The first beer company to use dating on its bottles to indicate shelf life was the
Boston Beer Company, makers of Sam Adams beer, back in 1985. The
notion of freshness dating didn't reach its current level of popularity until
Anheuser-Busch began promoting freshness dating as a “born on” date in

There are four things that impact a beer's shelf life.  The first is pasteurization -
the beer is heated for a short time to kill any harmful microbes in the brew. The
downside of pasteurization is that it can make the beer’s taste deteriorate

A second process is sterile filtration.  In this process the beer passes through
a mechanical system that removes any yeast or hops still present in the brew
that could continue an unwanted chemical reaction.

The third process is bottle conditioning.  In this technique some yeast remains
in the bottle to prevent oxidation that will lower the beer's quality.

The fourth factor isn't actually a process, but the recipe for the beer itself.
Beers with higher alcohol content or more hops in the recipe will take longer to
lose its freshness than beers with lower alcohol or hops. As a result, stouts,
porters, barley wines, Belgian Ales, and German Bocks tend to have the
longest shelf lives.

Proper purchasing techniques can increase the shelf life of the beer you buy.
Try to buy beer that isn't in a cooler section. Beer sitting at room temperature
can start to degrade quickly while cold storage slows the oxidation process
that takes place in a beer bottle. Oxidation is what gives your beer that flat,
cardboard taste after a period of time.

You should also look for freshness dating. Every brewery has its own way of
indicating this date, naming it something cute such as “born on date” or
“freshness date”. The date may be on the bottle, case packaging, or cap, but
this is a sure-fire indicator of how long the beer is going to taste great. If the
brewery doesn't use dating, you may want to steer clear.

Another indicator that beer has been sitting out too long to have much taste
left is dust. If the beer has been sitting long enough to get dusty, it just isn't
worth the risk. Leave it behind and move on. In similar fashion, avoid any beer
that's been sitting in direct sunlight, which spoils the hops and creates that
“skunky” flavor.

Avoid sales. While the price may look great, there is no such thing as a free
lunch, and a sale is there for a reason: to move the beer fast. Any beer that
needs to be moved fast is past its prime, and should be avoided.

To help your beer achieve it's maximum shelf life, respect your beer. Common
beer has a short shelf life of approximately six weeks. You can increase that a
bit by storing it at a temperature between 55 and 60 degrees Fahrenheit and
keeping it out of any form of light.

A very general rule of thumb is that most beers  in a bottle will have a shelf life
of approximately 8 to 12 months if properly handled. Keep in mind that shelf
lives are from time of bottling, not time of purchase, and plan accordingly to
ensure that you have the best-tasting beer available.  

Now for the beers you buy at your local pub.  

I happen to really enjoy cask ales but they are not commonly found here in the
USA because of their short shelf life among other reasons. After filling the
cask at the brewery, the yeast in the beer causes secondary fermentation
(producing natural carbon dioxide), which maintains the beer's flavor and
keeps it fresh until it's consumed. The problem is that it microbes in the cask
can spoil the beer if it's not consumed within four to six weeks.

Like cask-conditioned beer, most keg beer doesn't require pasteurization or
filtering before being kegged. This means that more of the original flavor is
retained. The result is that, unlike  bottled beer, the taste of keg beer is not
affected by the heat process involved in pasteurization or by the filtering out of
aromatic ingredients.

Draft beer also scores over bottled beer with its mouthfeel. When pouring
beer from the tap, the rate of pour and the amount of carbon dioxide can
seriously affect the taste sensation. Because of the way they're stored and
served, draft beers give much better mouthfeel when poured by a competent

And if you buy that growler from your local brew pub it will likely taste good for
only a week or less.  Then again, if you have it around that long without
drinking it why did you buy it in the first place?
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