On May 4, 1964 Congress designated Bourbon Whiskey as a “distinctive product of the United States.” Along with that title came a set of Federal regulations to keep the product consistent and its standards high. Among the many rules that make bourbon what it is are:

• Bourbon must be made of a grain mixture that is at least 51% corn.

• Bourbon must be distilled to no more than 160 (U.S.) proof (80% alcohol by volume).

• Neither coloring nor flavoring may be added.

• Bourbon must be aged in new, charred oak barrels.

It’s that last one that is causing a bit of a problem for bourbon distillers now, 51 years later.

As the construction industry continues to recover from the housing crisis the wood to make the barrels has become harder for bourbon makers to get their hands on.

A report in today’s Wall Street Journal notes U.S. sawmill production of wood like the kind used to make bourbon barrels dropped from almost 12 billion board feet in 2005 to half that in the throes of the housing crisis. Five years later the projected output for 2014 is less than 9 billion board feet.

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Then there’s what some call the “Mad Men Effect.” As the hit TV show, which features characters drinking on and off the job, grew in popularity, so did the love of cocktails. Bourbon production in particular has gone from about 700,000 barrels in 2001 to 1.21 million in 2011.

“A few years ago everybody wanted vodka drinks,” notes Yahoo Finance’s Aaron Task. “Now everybody wants bourbon and whiskey drinks. Bourbon is a very specific thing, it has to be made in a very specific way in these barrels...and there’s just not enough of it.”

Yahoo Finance Senior Columnist Michael Santoli says there are two ways the shortage could play out:

Higher prices for bourbon itself or you have to change the regulations to make it less restrictive. So does that mean you have to go against hundreds of years of tradition and say you can reuse the barrels or you can kind of make it somewhere else or somehow loosen the parameters.

It seems highly unlikely that the good folks in Kentucky, where the liquor must be made to be labeled “bourbon,” will budge on the rules and so higher prices are the likely result.

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Editor's note: An earlier version of this story erroneously stated that bourbon must be made in Kentucky to be called bourbon. While 95% of it does come from the state it is not a requirement.