Cheers to the Wall Street Journal for a deciphering the code large brewers use in listing “freshness dates.” (Unfortunately, WSJ is a paid site, so we only linked to the front page).

It begins: “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.”

But reporter Bruce Knecht reveals some of the secrets. For example:

Take Sapporo, a Japanese beer we purchased in Los Angeles, which was imprinted with “K1205FL” on the bottom. Lost in translation? Well, the code indicates the beer was made Oct. 12, 2005. In the case of Sapporo, the first letter represents the month of manufacture: “A” for January, “B” for February and so on, through “M” for December. (As if the system weren’t complicated enough, this one, like many of these codes, has an extra twist: The month code skips over the letter “I” and uses “J” for September.) The next two digits, “12,” refer to the day of the month, and the two numbers after that, “05,” are the last two digits of the year.

Corona uses two different alphabetical codes. The year, the first character, is coded from A for 2001 to F for 2006, while the months go from L for January to A for December. The day of the month is expressed numerically. So the bottle we bought with the code “EE08” was made Aug. 8, 2005. The company doesn’t publicly disclose its code, but people familiar with the company’s practice confirm our translation.

Track down a copy of the Weekend edition if you can, or find it in your local library. The story includes a chart telling you how to read the code on 15 beers, ranging from Anchor to Tecate.

Although “skunky beer” is at the center of the story, it doesn’t exactly explain how that ties into freshness. So just in case you were wondering . . .

Few beer tasting terms are more descriptive or straightforward than “skunky.” Quite simply, a skunky beer emits an aroma it didn’t have when it left the brewery.

The smell is the product of the chemical reaction that takes place in the bottle when bright light strikes the hops, creating what’s technically known as “light struck” beer. The reaction is stronger with paler and hoppier beers. The resulting chemical is identical to that in a skunk’s defense system, and light-struck beer puts off one of the most powerful aromas around.

Green and clear bottles do little to protect a beer from skunking, and while dark brown bottles are much better they are far from perfect. Because many of the best known imports come in clear or green bottles consumers have come to associate a skunky aroma with imported, often more expensive beer. That doesn’t mean their brewers intended them to taste that way.

The brighter the light and the longer bottles sit in that light the stronger the skunky smell will be. Even dark brown bottles won’t guard a beer from the bright fluorescent lights popular in grocery stores and many other beer retail outlets for very long.

You don’t have to settle for that beer. In some stores you’ll see six-packs sitting on tops of cases. Don’t grab that one, but get your beer from inside the case. A sealed case is even better. If you want beer from the cooler don’t be shy about asking if there are unopened cases in the cooler and buying a six-pack from one of those.

Buying beer that has been kept out of the light gives you a better chance of getting a “skunk free” beer. It’s up to you to keep it that way — mostly by continuing to keep it out of direct light — until you drink it.

You might already know that the name of bock beer comes from the German town of Einbeck. But did you know this?

“About the composition of Einbeck beer we learn that is was made two-thirds of barley malt and one-third of wheat malt, but lightly kilned, and was brewed only in winter. Of course, it was a top-fermented beer, ‘but very different from the top-fermented beers of nowadays,’ and is said to have been hopped very strong, and with hops that grew in the environs of Einbeck, where numerous hop-yards were in cultivation.”

John Arnold wrote that in Origin And History Of Beer And Brewing, one of two books rich in beer history recently made available in reprint form from BeerBooks.com. The other is Louis Pasteur’s Études sur la Bière (Studies On Fermentation).

BeerBooks.comfounder Carl Miller said he has seen a strong and growing demand for rare and early brewing literature in recent years. We hope this is a sound business venture, because we’ve long benefited from his affection for beer history. Visit BeerHistory.com to see what we mean.

“We’re reprinting these works because beer enthusiasts have become more sophisticated in the types of material they seek out,” Miller said. “Many have moved beyond the contemporary books on brewing history, and want to go a little deeper. They want to get closer to the roots of the subject, and these books help them do that.”

Miller contracted with a leading library preservation institution to digitally scan, enhance and reproduce each book directly from a first edition copy. “We want readers to see the pages as they were first published,” he said. “Illustrations, original pagination, even graphic style and page layouts can be almost as important as the text itself.”

Arnold makes the scope of his book apparent in the introduction, writing he was guided by “the conviction that a history of beer ought to be written only by duly weighing the intimate connection existing with the general cultural history of those race, nation, peoples who habitually make and consume it, in so far at least as it is a history dealing not merely with the technical development of brewing.”

The book doesn’t contain much that happened after the 18th century and doesn’t try to be a comprehensive history – for instance, leaving much of what occurred in England to other texts.

It’s hard to imagine now, but before Pasteur proved them right in the mid-19th century, the few biologists who held that yeast was the cause of, and not the product of, fermentation were ridiculed. Manufacturers of wine, vinegar and beer didn’t know if a week or two after production they’d have something they could sell or would have to dump – and the scientific establishment offered no help.

That set the state for Pasteur to prove that living cells (yeast) were responsible for forming alcohol from sugar, and that contaminating microorganisms turned the fermentations sour. He identified and isolated the specific microorganisms responsible for normal and abnormal fermentations in production of wine, beer, and vinegar. He showed that if he heated wine, beer, and milk to moderately high temperatures for a few minutes, he could kill living microorganism and thereby sterilize (pasteurize), the batches and prevent their degradation.

It should be surprising that the sub-title of Studies on Fermentation is The Diseases of Beer, Their Causes, and the Means of Preventing Them.

In the preface, he writes: “I need not hazard any prediction concerning the advantages likely to accrue to the brewing industry from the adoption of such a process of brewing as my study of the subject has enabled me to devise, and from an application of the novel facts upon which this process is founded. Time is the best appraiser of scientific work, and I am not unaware that an industrial discovery rarely produces all its fruits in the hands of its first inventor.”

As Randy Mosher points out in Radical Brewing, ancients were clearly aware of the magic yeast (the Sumerians had 50 words for it) performed. But today we’re happy today to still marvel at that magic and not end up with sour beer (unless, of course, that’s what you want). You don’t have to read Pasteur to understand why, but it’s as close as we’ll ever come to listening to him discuss his breakthrough work.

Be warned that these books are neither light nor necessarily easy reading. Pasteur was writing late in the 19th century, in French and interested in communicating with scientists and brewers trained in science. Arnold first wrote Origin and History in German, then it was translated into early 20th century English.

And, for obvious reasons, you won’t find anything about modern brewing practices or beer’s role in contemporary society. Arnold makes reference to the temperance movement that would soon bring Prohibition to the United States, but obviously you won’t find him comparing the roles of spirits, wine and beer in American society with that after Prohibition was repealed.

You’ll have to connect the dots. If Miller is right, a growing number of beer enthusiasts are inclined to do that.

What would Ben Franklin have drunk?

Perhaps something like Poor Richard’s Ale, the beer that officially goes on tap tomorrow to commemorate the 300th anniversary of Franklin’s birth (Jan. 17). OK, some of the 100 or so breweries across the country that brewed this special beer already have it on at others the beer isn’t quite ready to serve, but the Tuesday is the day to raise a glass to Ben.

So before you ask, here are a few answers.

Where can I find the beer?

The Brewers Association has compiled a list.

Even brewing giants Anheuser-Busch is involved. Its St. Louis Brewery will offer Poor Richard’s Ale to guests who visit its Tour Center from 10 a.m. to 4 p.m. A special toast led by a Benjamin Franklin historical role performer and A-B brewmaster will be conducted at 1:30 p.m. to honor the real Benjamin Franklin.

How was the recipe chosen chosen?

The Brewers Association held a competition to identify a suitable recipe. A panel of award-winning brewers and others with an eye toward history chose the recipe for Poor Richard’s Ale.

The winning recipe came from Tony Simmons of Pagosa Springs, Colo., who is in the process of opening a microbrewery. Simmons carefully researched his recipe, citing more than a dozen publications when presenting his entry. He wrote:

“Ben Franklin’s favorite type of beer could have been similar in gravity and strength to the modern version of an Old Ale (1.060 to 1.086). Franklin’s own writings refer to, ‘the type of strong, harvest-time ale, or October ale.’ Yet, his regular drink couldn’t have been excessively strong because he was known to have intellectual discussions in Taverns while, ‘lifting a few pints of ale,’ and Franklin felt (along with many of the time) that ale was a healthful tonic if consumed in moderation. In researching the era, I believe that due to the high cost of imported hops and the documented hop shortages in Colonial America, the hopping rates would have been appreciably less than that of Old Ale and more comparable to a Strong Scotch Ale.”

Bill Brand, who writes for the Oakland Tribune and maintains a Beer Blog, was one of the judges and described the decision process, concluding:

“John Harris loved number two (the eventual winner) and eventually he brought the rest of the panel around. He blew away my phenol argument. This was Colonial Philadelphia, he said. Beer was made quickly, placed in wood casks and served in a tavern without benefit of refrigeration. An off-note or two was to be expected, he said. The problem with number three was it was too perfect; it was an excellent, very drinkable beer. Could it have been produced in Franklin’s day? That argument carried the day.”

What makes the beer different?

For one thing, molasses and corn. As Simmons noted, “Modern appreciation for the characteristic molasses flavor is limited at best.” However both were common in ale during colonial times and each would have helped to reduce the colonists’ dependence on imported British ingredients.

Will every batch taste the same?

You already knew the answer was no, but one brewery had a particular problem following the recipe. The Salt Lake City Tribune reported:

All of them except one will follow a recipe for Poor Richard’s Ale that emulates a beer the forefathers might have enjoyed after a heated democratic debate.

The exception – you guessed it – is Utah, where not even American history can trump the 3.2 beer law.

“The rest of the country is going back to colonial times, but we’re going back to Prohibition,” joked Matt Beamer, head brewer at Park City’s Wasatch Brew Pub, the only Utah brewery participating in the anniversary celebration.

Beamer said he would love to join his national brewing colleagues and make the original ale, which contains 6.6 percent alcohol. But since Utah liquor laws prevent that, “I’ve just decided to have fun with it,” he said.

The best part is that this beer will be enjoyed on draft in pubs and taverns, where people still gather to talk – about beer, the football playoffs, maybe even revolution – just as Ben Franklin and his friends did nearly 300 years ago.