With more beers to choose from in the market, not only is it more difficult to decide what to drink, but beer potentially sits longer on the shelf. For a better beer drinking experience, consumers should learn the answers to these questions: How long does beer last?

And, how do I know when it is bad?

Beer is frequently referred to as liquid bread. Both use similar grains and yeast to complete the process, and just like bread, the flavor of a beer starts changing as soon as it is produced. Think about the taste of bread right out of the oven, versus bread that is a day old, or has been sitting out for a week. Fresh beer at the brewery will always taste different (usually better) than beer that is a month old, or a year old. And, just like bread, the taste can either be undesirable but have no ill effects, or it may have gone bad and can make you sick.

So, we need to break the question—and the answer—down into two parts. First, when does the flavor in beer change so much that you no longer enjoy drinking it (but it won’t hurt you)? And second, when has it spoiled and is harmful to consume? First, let’s talk about beer retaining its good flavor.

If you taste a beer right out of the vat at the brewery, it is similar to eating bread right out of the oven, only colder, and you are probably having a better time with your friends. The flavor of all beer starts changing the moment the beer gets exposed to air during packaging and starts aging. The same thing happens to wine, except more slowly, due to the higher alcohol content. So, the honest answer is somewhere between three months and multiple years. The oldest beer I have drunk was 20 years old, and was delicious.

The things that “kill” or damage beer are heat, air (oxygen), and light.

If a beer is exposed to heat (above 260 C), it causes the chemistry of the beer to break down, making the beer taste worse, and eventually it can make you sick. Storing beer below 4.50 C can more than double the length of time a beer retains its flavor, because it slows the chemical processes that breaks it down (the same reason milk lasts longer in the refrigerator).

Oxygen chemically interacts with beer and accelerates changes that cause beer to go flat or taste bad. Finally, ultraviolet light interacts with chemical compounds, especially hops, and causes the beer to taste sour, or “skunky.” That is why beer bottles are always made of dark glass, and canned beer often retains flavor better than bottled beer, because it protects completely from light and allows no air to enter.

So, if there is no refrigeration, and the beer has not been exposed to light and the cap is very secure, generally, a beer’s flavor is good for about six months for most light lagers (think Gorkha, Arna, etc.). If the beer is stored improperly, for instance in a place that is too warm, or in the sunlight of a window display, it may taste bad in less than six months. Conversely, with proper, temperature-stable refrigerated storage, no light, and good packaging, even light lagers can still be drinkable for a year or even longer. In Nepal, most outlets do not keep beer consistently refrigerated, so this is why the local brewers tend to set the expiration date at six months.

For craft or specialty beers, which are engineered for richer flavors, this rule may not apply at all. Some beers are very light, with floral notes and unique ingredients, for instance, jasmine, or the use of dry hopping. These floral and hop aromas, plus the herb flavors, begin dropping out of the beer almost instantly, so these beers may taste very different in only three months, even with refrigeration.

Conversely, others have high alcohol content and flavors of brewed tea, caramel, dark fruit, or toasted bread, and these flavors can last literally for years, or morph into other delicious combinations. Some barrel-aged beers are not even packaged for sale until after the first year, and can be kept in the cellar for years to come. And, even if the flavor changes, it may become more enjoyable over time, similar to wines. The result is that, the beer may still be good to consume for years (think Chimay or Yeti stout). As a consumer, it can be a delicious adventure to find out when in the aging process you prefer to drink a beer.

So, how do you know?

To help guide consumers, local beers are stamped with an expiration date, and most imports have either a “best before” date or at least a date on which the beer was packaged. Unless the beer is stored improperly, it should be enjoyable through the stamped dates. For beer with a “packaged” date, it depends on the beer style, and you can reference the chart below for general recommendations. But, remember that if you compare a fresh beer to one that is six months old or older, it will taste different.

Unopened Beer

Stored at Room Temperature

Refrigerated Storage

 

Shelf Life

Shelf Life

Canned beer lasts for

6 to 9 months

6 months to 2 years

Bottled beer lasts for

6 to 9 months

6 months to 2 years

Craft beer lasts for

3 to 12 months (maybe longer)

3 months to many years

Homemade beer lasts for

6 to 9 months

6 months to 2 years

The United States, for instance, does not mandate expiration dates on beer, because, like wine, it may be good for three months, or 10 years (or more). It is up to the retailers to control quality, and you as the consumer to define your preference. Consumers should not be afraid to return a beer that tastes bad, or seems to be past its prime. And, you might get a delicious bargain in buying a well-kept beer that is on sale to clear older stock.

How do you know when beer has spoiled and is harmful?

Beer can spoil anytime if not stored properly, and you don’t really know until the beer is opened. So, there is no set rule about when a beer has become harmful, but here are some indicators.

If the can or bottle is damaged in any way, or if the label is peeling or looks very old you should treat it as suspect. Next, beer should have the “pfssst” of fizz when opened. If the beer is flat or smells bad (just like other foods), it may be harmful. You should also check the appearance. If a light lager appears dark, or if the beer is cloudy, it may be harmful to consume (but note that some beers are intentionally hazy; for instance, bottle-conditioned beers, a German-style Hefeweizen, or some American IPAs).

And finally, taste. If the beer tastes like cardboard, has a metallic or acid flavor, or tastes like spoiled raisins, it most likely should not be drunk. Do not drink a beer that smells or tastes spoiled. Any reputable retailer should exchange a bad beer for a new one. Most importantly, enjoy exploring new beers in the market. It’s a delicious way to expand your tastes while also spending time with friends and loved ones. Cheers!

(For more in depth knowledge, I recommend you check out FLAVOR, FOAM and FRESHNESS: Practical Guides for Beer Quality; by Charles W. Bamforth at the University of California at Davis.)

Jim Jones is an American craft beer exporter who recently opened The Yeti Taproom and Beer Garden, home to dozens of beers, in Kathmandu. He can be reached at ----(https://www.facebook.com/YetiTapRoom/ or jimjonesdenver@gmail.com).