Yes, you can drink expired beer. Beer does not spoil the way milk or meat does, so a can past its “best by” date will not make you sick under normal circumstances. What actually happens is the flavor fades: hops fade, malt turns papery, and carbonation drops off. The date on the can is a quality marker, not a safety cutoff.
Why Beer Does Not “Go Bad” Like Food
Standard alcoholic beer is naturally hostile to the pathogens that cause food poisoning. Its low pH, hop compounds, alcohol content and lack of significant free oxygen inside a sealed package make it a poor environment for the bacteria you’d worry about in dairy or meat. A 2023 Journal of Food Protection study covered by Cornell Chronicle backs this up, showing that conventional beer’s mix of hurdles keeps it microbiologically stable well past its printed date.
What changes instead is oxidation. Every can or bottle traps a small amount of oxygen at packaging, and over time that oxygen reacts with the beer’s compounds, dulling hop aroma and turning bright, malty flavors into something closer to wet cardboard or stewed tomato. Heat and light speed this up dramatically, which is why a beer left in a hot car or under fluorescent light skunks out far faster than one kept cold and dark.
How to Tell If a Beer Has Actually Gone Bad
A few signs are worth checking before you pour:
- Skunky smell. Caused by UV light hitting hop compounds, most common in clear or green glass bottles left in sunlight.
- Flat carbonation. Age and temperature swings let CO2 escape faster than expected, leaving a beer noticeably lifeless.
- A swollen or leaking can. This is the one actual red flag. A bulging can can mean an unwanted second fermentation from contamination, and it should go straight in the trash rather than a glass.
- Cardboard or sherry-like off flavors. Classic signs of oxidation. Unpleasant to drink, but not dangerous.
Which Styles Age Best (and Worst)
Hop-forward beers age worst. Pilsners and hoppy pale ales rely on fresh, volatile hop aromatics that fade within three to six months even under good storage, which is why breweries push “drink fresh” messaging so hard on IPAs. Malt-forward and high ABV beers hold up much better. Bottle-conditioned beers at 9% ABV or higher, like barleywines and imperial stouts, can improve with a year or more of age as their flavors mellow and integrate, similar to how a big red wine develops.
Unopened and refrigerated, most commercial beer stays reasonably close to its intended flavor for up to about two years past the printed date. Left unrefrigerated, that window shrinks to roughly four to six months before the taste noticeably declines.
FAQ
Can drinking expired beer make you sick?
Generally no. Standard beer is resistant to the pathogens that cause food poisoning. The main risk with a genuinely spoiled beer, like one with a swollen can, is an unpleasant taste rather than illness.
How long does unopened beer actually last?
Refrigerated and unopened, most beer holds up reasonably well for up to two years past its date. Stored warm, expect a noticeable drop in quality within four to six months.
Does this apply to non-alcoholic beer too?
No. Removing the alcohol changes the safety picture, so treat non-alcoholic beer like any other perishable beverage and respect the printed date rather than assuming standard beer’s shelf-stability rules apply.
What is the biggest red flag that a beer should be thrown out?
A swollen, bulging or leaking can or bottle. That points to contamination and an unwanted second fermentation, not just normal aging, and it should be discarded rather than tasted.
If you’re curious how carbonation loss specifically plays out, our piece on whether it’s safe to drink flat beer covers that exact scenario in more depth, and our Beer Statistics guide has more on how storage and shelf life get treated across different countries.
How to actually tell if a beer has gone bad
Trust your senses over the calendar. A beer past its prime usually announces itself in one of a few ways: a papery or wet-cardboard smell from oxidation, a skunky aroma if it spent time in a clear or green glass bottle under bright light, flat carbonation with no head at all, or a flavor that just tastes dull and off compared to a fresh version of the same beer. None of these make the beer dangerous to drink, they just make it taste worse.
The one genuine red flag is a can or bottle that looks physically wrong: a bulging or swollen can, a cap that has popped partway off, or visible mold around the cap or cork. That points to unwanted bacterial or wild yeast activity, and in that case the safest move is to pour it out rather than taste it.
Best by date versus a real expiration date
Beer labels almost never carry a strict use-by date the way milk or meat does. What you will usually see is a “best by,” “born on,” or packaging date, and that is a quality marker, not a safety cutoff. The US TTB’s freshness dating rules exist so wholesalers rotate stock and customers get beer close to its peak flavor, not because the beer becomes unsafe after that date. Beer’s own chemistry works against pathogens: its low pH, alcohol content, and hop compounds make it a genuinely hostile environment for the bacteria that cause food poisoning.
Does the style change how fast it fades?
Yes, considerably. Hop-forward styles like IPAs fade fastest, often losing their sharpest aroma and flavor within three to six months as the volatile hop oils break down, which is why IPA drinkers are told to buy the freshest can they can find. Pilsners and other pale lagers are similarly quick to decline once oxidation sets in. On the other end, high-ABV, malt-forward styles like barleywines, imperial stouts, and strong Belgian ales can improve with a year or more of cellar aging, developing sherry-like or dried-fruit notes as the beer mellows, similar to how a big red wine ages.
How to store beer so it lasts longer
Keep it cold and keep it dark. Heat speeds up staling reactions no matter the style, and light, particularly UV light hitting a clear or green glass bottle, triggers the reaction that produces 3-methyl-2-buten-1-thiol, the compound responsible for a “skunked” smell. Cans block light entirely, which is one reason canned beer often tastes fresher for longer than the same beer in a bottle. A cool, dark cupboard or a fridge beats a sunny kitchen counter every time.
