The growth of the craft beer industry is something of a double-edged sword for discerning beer lovers looking to get their money’s worth. With all the beer available, it can be difficult to make sure that the brew you’re buying is fresh.

Given enough time on the shelf, a beer’s taste can change dramatically, and end up far from where its brewer intended. Drinking an old, stale beer isn’t exactly the same as taking a swig of rotten milk — it won’t make you sick. But chugging a decidedly un-fresh brew won’t be what the brewer intended.

“You want the chef, or brewer, to be able to put forward their best example of what their product is,” says award-winning homebrewer and BrewviX judge Mike Herman. “Similar to how you wouldn’t eat a dish that has been sitting out cold for a long time, a lot of beer drinkers want the freshest possible beer.”

When does freshness matter?

Freshness is a big concern for IPAs and other hop-forward beers, like pale ales and pilsners. Those styles tend to change flavor more drastically as they sit on shelves because they rely on their hops for their flavors and aromas that deteriorate relatively quickly, leaving a sweeter, maltier brew.

“If you get a big IPA, you’re paying for the hops so you don’t want them to degrade,” says Alex Morris, manager of Pinocchio’s Beer Garden in Media. “It defeats the whole point.”

Lagers are also subject to flavor changes, resulting in “papery/cardboard and metallic notes” as the beer ages, according to the Brewers Association.

Other beers, however, last years or even decades, Monk’s Café owner Tom Peters says. Darker beers, like stouts; higher-alcohol beers, like barleywines; and barrel-aged beers, like sours, age well, and some specific brews even benefit from a little more time in the package. Peters, for example, owns a few beers from Chimay that date back to his first trip to Belgium in the mid-1980s, and he still enjoys them occasionally.

“They’re different,” after all that time, Peters says. “It doesn’t mean they’re better or worse, but they’re definitely a different product at that point.”

How can you tell if your beer is fresh?

Smart beer consumers know to check the date code on the can or bottle to determine its freshness. There is no industry standard as to how brewers date their beers, though most use a “bottled on” format. That style indicates when a particular beer was canned, rather than when it is best by.

Often, that date can be found on the bottom of cans, on the side of bottles, or on the case itself. Not all breweries date code their beers, but the practice is becoming increasingly common as consumers become more focused on freshness, said Ed Friedland, former craft and specialty marketing manager at distributor Origlio Beverage.

But with most breweries dating their beers using a “born on” date, as Friedland calls it, it’s up to consumers to know how long a particular style might stay fresh. Herman says it’s best to look for “the freshest possible beer,” ideally something packaged less than six weeks ago in the case of hoppy IPAs and double IPAs.

Pinocchio’s, meanwhile, hopes to have hoppier beers out the door within 30 days of the packaging date, while Origlio wants those beers off their floor within 90 days or less. Some breweries say their beer stays fresh longer. Evil Genius beer is good for six months, cofounder Trevor Hayward says, but they like to see the beverages consumed within 90 days of packaging. After all, fresher is almost always better.

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Can a beer be too fresh?

Beer can sometimes be too fresh — a concept known as “green beer.” As Herman says, the problem of overly fresh beers is most often in brews that are not allowed to “condition,” or mature, long enough before they are put up for sale.

Usually, Herman says, the “green beer” descriptor is applied to beers that undergo “excessive dry-hopping,” a brewing process that imparts hop aroma and flavor but keeps bitterness in check. These days, that typically means the popular hazy IPAs and double IPAs, though other styles can also suffer from being consumed too young.

Most often, the result is an immature brew that just doesn’t taste as good as it could, and might even result in “hop burn,” or an unpleasant mouthfeel that makes the beer difficult to drink.

“With a few more days, that should be OK,” he says. “But it’s a situation where you have beer nerds paying over $100 for a case of beer just to crack the first one and find out, ‘This isn’t what I wanted.’”

Lucky for beer lovers, Pinocchio’s manager Morris says green beer is rare. “It does exist, but I haven’t seen a lot of it,” Morris says. “If it’s a good brewer, you expect them to package [a beer] when it tastes its best.”

How do beer sellers make sure consumers are getting fresh beer? What should you do if you get a stale beer?

Beer sellers all along the supply chain have processes to make sure the brews they’re peddling are within an acceptable date range.

Distributors record and track their date codes closely, and adjust their buying of different beers to make sure that the brews don’t go stale, Friedland says. After beers arrive to Origlio, they are kept in cold storage, and delivered cold to retailers via insulated trucks to keep changes to a minimum.

“We try to get it shipped to us cold, we keep it cold, and hopefully within a handful of hours, it is in someone’s walk-in box staying cold,” Friedland says.

Retailers that sell the beer, like Monk’s and Pinocchio’s, keep the quality checks going by rotating new stock to the back of coolers, and moving up the older beers so that they will sell first. Those checks, Morris says, are a daily task at Pinocchio’s.

“The retailer is definitely the one who is the last line of defense to serve fresh, good beer,” Peters says.

However, if and when all that effort fails, some retailers opt to simply get rid of stale beer and take a loss. Some breweries, like Evil Genius, will credit or swap out the retailer’s old beer for newer brews in order to keep quality up — though, in Friedland’s estimation, that practice is somewhat rare in the industry.

If you do happen to get a stale beer, Peters says, just be cool about it, and bring it up to an employee at the shop “as diplomatically as possible.”

“Give the bartender or owner the opportunity to smell or taste it,” Peters says. “I think most people would like to get to the bottom of it.”

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