The Secret Code of Beer Expiration Dates

Beer — an alcoholic beverage brewed with hops, malt and barley; once referred to by Keats as “sweet liquid bread” — has a half life of about three months. Six months from the date of brewing, beer turns from inebriating mana into hobo swill. Then why is it that most American beers do not display their expiration dates, so consumer’s can pick the freshest brew possible?

According to this article, beers actually do — it’s simply written on each bottle in a secret code to confuse alcohol-addled consumers.

A loaf of bread has it. So does a carton of milk. But if you’re looking for the expiration date on a bottle of beer, forget about it – for many brewers, that information is a closely guarded secret.

There are now more bottles of beer on the store wall than ever – more than 2,000 domestic brands alone – making it harder for both stores and consumers to steer clear of the stale stuff. Age is critical: Nearly all beer begins to deteriorate before it even leaves the plant, partly due to oxygen in the bottle, and many experts say most brews are well past their prime after six months.

To identify when bottles and cans need to be yanked from the shelves, many brewers imprint them with cryptic letters and numbers that distributors can translate. The trouble is they look more like hieroglyphics to beer drinkers, and most makers don’t decipher them for consumers. But with the help of industry insiders and analysts, we cracked the codes, studying bottles purchased across the country to determine the key dates for 18 big brews.

The way the code works is this. Letters from A-M represent the month of the year. The next four digits are the day and year the beer was first brewed, and the last two letters are the state code where it was brewed. So you may want to stay away from that fifty cent close-out special at the local liquor store marked M0787DE. Oddly enough, Irish brews have clearly marked expiration dates… and our local off-license sells a variety of off-peak beers in foul-smelling wicker baskets for discount prices. Hobo’s delight.


Edit Your Comment

  1. drsmith says:

    I guess if you’re drinking corona, this might be important. However, if the bottle in front of you is brown in color, the age marker doesn’t mean a whole lot. The brown bottle best protects the beer from beer’s worst enemy: light. Green bottles are better than clear ones, but not by much.

    I’ve drank many gallons of beer(not in one day mind you), and some of them have been almost 10 years old! Swill? Well, if you want to give me your stash of 10 year old Barley Wine for 50 cents a bottle, I’m more than willing to take you up on that! Send it to me before it’s too late!

    Honestly, when beer is in the bottle it really doesn’t change much over time. If anything, a lot of brews actually improve. The date thing was a marketing ploy by Budwieser or one of the other big, tasteless beer makers to make buyers feel like beer snobs. In reality, it’s BS.

    • partofme says:

      You’re right that darker bottles help to reduce aging effects from light. However, complexiglass is definitely right that you will still taste a difference, even in a brown bottle. More than once, I’ve picked up a 6-pack without checking the dates. I remember two occasions quite well. One was a Boulevard beer, one was a German beer (I can’t remember which one, and if I did, I wouldn’t be able to spell it anyway). Even in dark brown bottles, I popped them open, took one sip, and knew immediately they had to be old. Sure enough, both times they were a little over a year expired. I remember them clearly because those are the only two times I’ve ever tried to return beer.

      You can reduce aging by dark bottles and nice environments, but it’s not BS. Beer gets old. And it gets crappy.

      • partofme says:

        And wow, was this really from five years ago? It just popped up in the “most popular” sidebar…..

        • gerald.saul says:

          Some outside website must have linked to this article and drove a lot of traffic to it…though, I’m surprised we don’t have more comments if that’s the case.

  2. Joel Johnson says:

    All true, but in some cases freshness does matter. A hefeweizen, for instance, is best when fresh. In general, though, it depends on the brand and style.

    But getting the freshest bottle isn’t always the point! Like you point out, Doc, some beers get better as they age. (Sierra Nevada’s Celebration, for instance.) It’s useful to tell how old a beer is either way.

  3. beerjerk says:

    Well said, mostly. Now how do I tell if the date is a “best by” date or a “produced on” date? I have a can of beer that says L 2006. So is it over a year old, or is it 2-3 months old?

  4. hern35 says:

    Is the beer with L 2006 a BITburger 16.9oz can? I purchase beer for the store i work at and i noticed the L 2006 on beer that showed up from the distributor on April 24, 2007. I cant seem to find the code for BITburger anywhere. The beer tastes fine, but not as good as the bottles. (which don’t have any codes on them) I want to make sure that the distributors aren’t peddling me old beer

  5. beergirl says:

    Its Simple… ask your retailer where the expiration date is on the package. All retailers should be educated on this topic to inform their consumers. Its not meant to be a secret code. Some suppliers have a born on date( when the beer was made) while others have a expiration date. All brewers/suppliers would love to have their customers enjoy their beer at the freshest and most enjoyable moment! Not everyone is out there to scam you!

  6. complexiglass says:

    Sadly most retailers have no idea what they are talking about when it comes to good beer.
    drsmith is correct the darker the bottle the less light can reach the beer which is why light is a good beers’ greatest enemy, hence why beers such as heineken and becks taste skunky straight out of the bottle no matter how fresh they are. The other major factor is the percentage of alcohol, as a rule of thumb anything over 8% ABV (alcohol by volume) should be cellarable for some time depending on the style of beer. In general relatively hoppy beers (Pale ales, and India Pale ales) have an absolute maximum life of around nine months after the brewers expiration date. Any true craft brewer will list an expiration date as opposed to the infamous “born on date” made popular by Miller/Coors and Anhueser Busch. Although hops act as a natural preservative (hence the invention of the India Pale Ale in the early 1800’s) hops still break down over time, eventually breaking down making the beer taste sweeter. drsmith is also correct in that many beers improve over time, many of these are marketed as bottle fermented, many bottle fermented beers can contain a live yeast which will allow the beer to continue fermenting even after the beer has been bottled. Either way I’m babbling for more information on different beer styles and how to hold on to good beer and drink it at its peak visit there is more info there than I could ever convey in one comment

  7. Jalbert says:

    If anyone else is finding this old article in the side column and thinks it might be a load of crap, it is. Here is a far more acurate response to it.

    • outis says:

      The fact that it’s under most discussed while having very few posts and being a few years old might be related to the commenters from midnight December 0, 0000.

      • NickRayko says:

        I saw it under “most popular”, not “most discussed”, and clicked through thinking that it was going to be a new article.

        @ jalbert: Good BYO link!

        • jesirose says:

          Agreed. How do they get those posts?

          Okay, so how do the letters from A-M represent the months of the year? I keep going through this,and the 12th letter is L….