Can Beer Go Bad?

In short, yes.

What makes a Good Beer Go Bad?

Three things can make a good beer go bad.


The safest place for any beer to be is in a keg. There are a few reasons for this. The first is that it is as dark as can be in there. This is a good thing, especially for a beer with many hops, high in International Bittering Units (IBU).

This is because light, especially sunlight, has colors in the spectrum of light that reacts with the hop oils. When these oils are “Light Struck,” it results in a “skunky” aroma.

The infamous Heineken and Moosehead “Stink” always brings back fond memories of the first apartments and all-night parties.

Why the Color of the Glass Bottle Leads to “Skunked” or “Light Struck” Beer.

First, the hop oils in a beer like the dark because light affects molecules in oils to break into a new compound that we perceive as resembling skunks’ odor.

Both sunlight and fluorescent lighting can have the above-described effect on the beer.

Naturally, clear glass offers the least protection. Light passes quickly through it can “skunk” a beer in a short time. Green-colored bottles provide some protection. (Note Heineken) Brown bottles block light the best providing the beer with the most protection.

Is all light equally bad?

Light causes beer to go skunky because the light wavelengths that cause a beer to skunk fall between about 350 and 550 nanometers. 350 nm is the upper end of the ultraviolet range, invisible to the human eye, and 550 nm is visible. These wavelengths are associated with purple, blue, and green.

Incandescent and halogen lights emit a broad spectrum of light wavelengths. While they emit wavelengths that cause a beer to skunk, the light color is skewed toward the longer wavelengths that do not cause this reaction.

LED and all fluorescent lights peak around 400 nm. This means LED, and fluorescent lights are worse than incandescent and halogen lights.

Interestingly, dark beers absorb a broader spectrum of light wavelengths than lighter colored beers. Hence, as beer becomes more golden in color, the propensity for “skunkiness” increases.


The second reason beer is so happy to be in a keg is the thick metal jacket that shields it from heat. Heat is the second enemy of beer. Heat causes the proteins to break down and oxidize.

Heat doesn’t create off-flavor. It speeds up oxidation. Oxidation causes some beers to develop a cardboard-like flavor.

Malty beers can develop a sweet, toffee flavor, and a beer’s “hoppiness” is also affected by heat. The bitter sensation will linger, but the aromatics will vanish.

It is also essential to keep in mind that beer bottles (and crown caps) are expanding and contracting with temperature change in addition to chemical reactions. Temperature change also causes pressure changes.

Heat Can Make Beer Taste Old

According to Craft Beer USA, “A general rule of thumb for the brewing industry is that beer stored at 100°F for one week tastes as old as beer stored at 70°F for two months, or as old as beer stored at 40°F for one year.”

Two Experts on The Effect of Heat on Beer

“For instance, temperature extremes during shipping, warehousing, and at the retail store, you purchase your beer from can double the “aging” of the beer for each increase of 10 deg. F. That means beer with a “shelf life” of 6 months at 40 F will have a “shelf life” of 3 months at 50 F and 6 weeks at 60 F.”​

Mark Ruedrich, Brewmaster, North Coast Brewing Company

“Shipping and storage temperatures are important to beer flavor. Beer contains a variety of compounds that are capable of autoxidation if temperatures get high enough. In practical terms, a beer that has been held at 38° C (100° F) for two weeks will have the same loss of freshness in flavor as a beer that has been held for three months at 21° C (70° F) or beer that has been held for more than one year at 4° C (39° F).” ​

Handbook of Brewing by William A. Hardwick, 1995


This is either a friend or foe of beer. If the beer is less than eight or nine percent alcohol by volume (ABV), it would be best to consume the beer as soon as possible. Once the ABV goes above ten percent, letting that beer rest in the bottle for a few years can be advantageous. The higher the ABV, the longer it can rest. I have enjoyed sampling a Special Vintage Fuller’s Ale over twenty years old. It was an almost vinous experience. But one hundred percent an excellent ale.

On the other hand, I have sampled a ten-year-old Helles that was one of the more unfortunate flavor experiences I have had to date.

 How long does unopened beer last kept at room temperature?

It depends on storage conditions. In an ideal situation, to maximize the shelf life of unopened beer, it is best kept at a temperature between 45° F and 55° F. Properly stored, unopened beer will not lose any character for about 4 to 6 months when stored at room temperature.

How long does unopened beer last in the fridge?

Properly stored, unopened beer will generally stay at best quality for about 6 to 8 months in the refrigerator. However, it will usually remain safe to use after that.

Do Different Beers Last Longer Than Others?

Stronger beers have a longer shelf life, like imperial stouts and barley wines. In fact, many of these beers actually benefit from age, acquiring richer flavors. Sour and wild beers will also develop interesting new flavors with age. These beers evolve over time because of the mix of yeast and bacteria.

Aging beer requires cool, stable temperatures in an area out of light. Like aging wine, there are many complexities and variables. We recommend reading Vintage Beer by Patrick Dawson for more on aging beer.

For the majority of beer, how long it lasts depends on how it was packaged.

What is the Best Way to Store Beer?

Bottled Beer

Kept in the dark and cold area, like a fridge. Bottled beer will last up to 6 months. Keep away from light to prevent skunky off-flavors.

Canned Beer

Can provides the best protection against oxygen and light. Canned beer is best before 6 months if stored cold and 3 months if kept warm.

Kegged Beer

Kegged beer should always be stored cold.

Non-pasteurized kegs will start losing it after 45 to 60 days. For pasteurized barrels, the shelf-life is 3 to 4 months.

If you purchase a commercial keg and use a party pump, it will last about 12 to 24 hours once tapped because air is pumped to push out the beer, causing oxidation.

Growlers and Crowlers

This beer is meant to be drunk fresh. Unless a counter-pressure filling machine is used, the beer is exposed to a lot of oxygen when it’s filled. Drink a growler or crowler within 36 hours of being filled.


Can Beer Go Bad?

Yes, it can. But it doesn’t have to.

Most beer will last just as long as necessary if the proper care is taken.

If beer is a “session” beer, by definition, it is not a beer that you will keep for a long time. In fact, if you haven’t finished it by the time you spend reading this blog post, it is probably flat by now. Shame on you!

If you have a Russian Imperial Stout that is more than 10% ABV, it would be good to think about opening it a year or two after getting it.

I used to brew a 15% Imperial Stout in five-gallon batches and bottle the brew in old “Cold Duck” sparkling wine bottles. I used them because they would take a crown cap. These bottles I would label with the date it was bottled, and they would be given to folks looking forward to something like having a child or buying a home.

When I gave them the bottle I would tell them they should open it when the mortgage is burned, or the youngster reaches legal drinking age.

Most of the two batches I brewed were correctly opened when adequately matured. The others were enjoyed earlier in their youth.

Notify of
Inline Feedbacks
View all comments

First, let me introduce myself. I am Peter LaFrance, author of Beer Basics and Cooking & Eating With Beer, (John Wiley & Sons, Inc. – 1995). I have also been published in American Brewer, All About Beer, and Ale Street News.

I have been writing about the brewing industry since 1984. Credits include contributing editor for Restaurant Management and Top Shelf magazines. I have also written for Beverage Media, New Brewer, Beverage Dynamics, and All About Beer magazine.

Welcome to The Old Growler!

Follow The Old Growler

Would love your thoughts, please comment.x