Determining just how fresh the beer at your local grocery store is can be a challenge, due to inconsistent labeling by breweries. (Matt Brooks/The Washington Post)

Before craft beer aficionado Matthew Starr buys a new IPA or Pilsener at his favorite beer store, he picks up the can to check for a date. “I will look for a date code 100 percent of the time,” the 35-year-old D.C. attorney said. “I’ve had too many bad experiences over the years with out-of-date beer that I’m not willing to gamble anymore.”

Starr says he prefers to drink his IPAs within six weeks of canning, to fully appreciate the aromatics and flavors. If he’s not buying a beer at a brewery, “I will not buy an IPA if there’s not some sort of date on the bottle or can.”

For those who just grab a six-pack off a shelf at the nearest grocery store, this quest for freshness might sound weird, but Starr’s not alone. Austin Ryer, the D.C. manager for craft beer distributors Legends Limited, said he has seen customers “turn away a perfectly good IPA because it was more than 45 days old, even though it was well within its ‘best-by’ range,” as determined by the brewery. In one extreme case, he watched a man “tear apart a 30-case display of Budweiser just to get an 18-pack with a born-on date only a week fresher than the rest of the display.”

By now, consumers have gotten the message that most beer is best enjoyed when it’s fresh. Ninety-five percent of craft beer drinkers cited “freshness” as important in a 2016 Harris Poll. But figuring out when, exactly, that is can be a challenge: Every brewery has its own method for determining how long its beer is considered “fresh,” and within the industry, there are no standards governing how freshness dates should be communicated to consumers. (It’s worth noting that there are no official government standards for the “sell by” or “use by” dates on eggs or milk at the grocery store, either. The only product for which the Food Safety and Inspection Service regulates sell-by dates is infant formula.)

There is no standard way for breweries to share how fresh their beer is. Stone Brewing (left) is one of the best in the industry, telling drinkers not only the place (Richmond Virginia) and the date where its Double IPA was bottled, but the date by which it should be consumed. New York's SingleCut Beer (center, top) says its beer should be drunk within 7 to 21 days of canning. This beer was made on June 13, though the label doesn't say what the date on the bottom represents. Flying Dog (center, middle) says this blood orange imperial IPA will be best before Nov. 11, but doesn't tell you how long it has been in the bottle. Tree House uses the date stamp on the bottom of the can for jokes, including poking fun at Ravens QB Joe Flacco. Like Stone, Boulevard Brewing (right) includes both “Bottled on” and “Best before” dates on its bottles. It doesn't mention on the bottle that the top string of numbers is actually the date and time of bottling. (Fritz Hahn/The Washington Post)

Some breweries simply stamp a date onto the bottom of the can, which is usually a “canned on” date, even if it doesn’t say so. Others provide an “enjoy by” date somewhere on the label. Each method has its inherent flaws. Just providing the “born on” date assumes customers know how long a particular beer or style is good. A “best before” date is more helpful, but it doesn’t clearly tell a customer how fresh a particular beer is.

Flying Dog’s “enjoy by” date is 170 days after bottling; Sierra Nevada’s is 150 days; Stone Brewing’s beer could be anywhere from 90 to 120 days. Trying to figure out the age of the six-pack on the shelf in front of you from its canning date can take some serious mathematical gymnastics.

Stone’s “Enjoy By” IPA series makes it easy, putting the expiration date front and center in the beer name, and giving drinkers 37 days from the brew date to buy (or finish) a six-pack before it’s pulled from stores. But then there are breweries such as Lagunitas. Not only does it make codes difficult to read by stamping black ink on the neck of a brown bottle, it uses Julian dating, so that, for example, the number “154 7” would signify that the beer was bottled on the 154th day of 2017, or June 3. Good luck deciphering that without Google.

Why is there such a range of how long a beer is “best by”? The difference comes down to science. Well, hops and science. Any brewer will tell you that the hops in a beer begin to degrade almost immediately after it’s made, and that this problem is especially acute with beers that are dry-hopped specifically for their aromatics — like most of the juicy IPAs that are trendy . They’ll also tell you that the biggest threats to off-flavors in beer are oxygen and light. Limit those, and you’ll have a longer shelf life.

Stone's Enjoy By IPA is only sold in stores for 37 days to guarantee its freshness. The "expiration date" is printed in large numbers right on the can. (Fritz Hahn/The Washington Post)

Smaller brewers who make beer with heavy doses of tropical-scented hops generally recommend drinking within a month of packaging. Richard Thompson, the head brewer at Herndon’s Aslin Beer, which has become a favorite with beer traders, says that his hazy, dry-hopped IPAs hit their sweet spot two to four weeks after canning, before beginning to decline. Dan Bronson, the general manager of New York City’s highly regarded SingleCut Beersmiths, suggests a one-to-three-week window for its hoppy IPAs and double IPAs.

“Though these beers are still really enjoyable six weeks on, you’re starting to stray away from what our brewers intended,” he said. “After a month or so, the aroma and vibrance of the hops starts to fade, and the all-important balance the brewers lost sleep over is gone.”

At the larger end of the industry, there’s more latitude. Firestone Walker is “best enjoyed” within 120 days, while Bell’s said “the vast majority of our beers” are good for six months, with the exceptions of lagers (three months) and the cult double IPA Hopslam (drink as soon as possible).

As craft beer’s national and global reach expands, and beers are shipped longer distances, breweries are trying different ways to get beer into new markets without sacrificing freshness.

A few years ago, Flying Dog spent a significant amount of money — $75,000 to $100,000 — according to Chief Operating Officer Matt Brophy to add what it calls “a very sensitive analytical system” to measure the amount of dissolved oxygen in its bottles and cans. The results have been impressive, Brophy says, enough that Flying Dog extended its “enjoy by” date from 140 days to 170 days from packaging without complaints from consumers.

Chief Operating Officer Matt Brophy and Flying Dog have spent big bucks trying to extend the freshness of their beer. (Courtesy of Flying Dog Brewery)

Anheuser-Busch brought “born on” date labeling into the mainstream in 1996 and gives Budweiser and Bud Light a shelf life of 110 days: The global giant and convenes regular “freshness panels” with blind tastings and invested in new technology, including a proprietary cap liner that absorbs any oxygen in the bottle. And it announced last month that it will spend $82 million to build new distribution facilities in Los Angeles and Columbus, Ohio, and beef up its national supply chain to fresher beer into stores.

In an ideal world, more breweries would be like Stone and Boulevard, which clearly communicate both the bottling and “best before” dates. Greg Koch, the co-founder of Stone, says the brewery has focused on freshness and short shelf lives since it opened in 1997.

“We make a big deal of it,” he said. “We think that’s how people are going to be able to enjoy Stone at its best.”

At the same time, he says, some of the ultra-fresh fetishism can be a bit extreme. “Yes, I can tell some subtle differences between a three-day and a 37-day Enjoy By. However, the enjoyment level doesn’t change within the 37 days.” On the other hand, he adds, “I’ve seen on beer discussion forums and whatnot that there will be somebody who says they wouldn’t have a beer that’s more than two weeks old. Okay. It’s not necessary to be that rigid. But I believe in their ability to make that informed decision if that’s the way they want to go.”