At first it sounds like a godsend: Some lucky distiller discovers three barrels of long-forgotten whiskey buried in the depths of a Scottish warehouse. Not only is it drinkable, it's good—there's enough booze to make many bottles. And yet one can't help but admits this smacks of marketing voodoo, another gimmick to sell the leftovers. Modern-day pirate finds buried liquid treasure? Get real.

Like it or not, you may be seeing a lot more lost ("orphan") barrels in the next few months.

James Espey is at the forefront of the movement. A retired executive once considered a major force in the liquor business (he was behind iconic brands like Johnnie Walker and J&B Rare), he and his two business partners, Peter Fleck and Tom Jago, launched The Last Drop Distillers in 2008; their first spirit was a 1960 Blended Scotch Whisky originally barreled in 1972. Most of the stock was sold off years ago, save for the three barrels that The Last Drop purchased for an undisclosed amount from Scotland's Auchentoshan distillery. Despite succumbing to years of evaporation (known as the "angle's share"), there was still enough liquid to fill 1,347 bottles. The asking price? About $2,000 per bottle. In the six years since its initial release, the value of the bottles has doubled.

Pictured, from top: Orphan Barrel's 26-year Old Blowhard Whiskey, 20-year Barterhouse Whiskey.

More recently, Espey released a 1950 cognac and a 50-Year-Old Blended Scotch Whiskey, the latter of which amounted to a total of 388 bottles with an asking price of $4,000 a pop. So how does he track down lost barrels? Industry connections help; Mike Keiller, president and CEO of Morrison Bowmore Distillers, worked with Espey on the latest offerings.

"I told Mike that I was looking to find old barrels of whiskey," Espey says. "I do this as a hobby, if I did this for a living, I wouldn't make any money."

Lost barrels are not a new thing, of course. The Francis X. Aubrey, a steamboat that sunk in the Missouri River back in 1856, was supposedly hauling 400 barrels of Kentucky bourbon. Over the years, groups of treasure seekers have tried unsuccessfully to find the missing barrels. To no avail.

In 2011, Buffalo Trace got in on the action by releasing bottles of rare bourbon from Old Charter, which it acquired back in the late 1990s.

And then there is Diageo—the world's largest premium drinks company known for Johnnie Walker and Bushmills among others, with distilleries in the United States, Canada, and Europe—and which launched the "Orphan Barrel Whiskey Distilling Company" last year. In February, the company released its first two spirits: a 20-year Barterhouse Whiskey ($75/bottle) and a 26-year Old Blowhard Whiskey ($125/bottle). Last month it released a third bottle called Rhetoric, a 20-year Kentucky Straight Bourbon. The company plans to progressively age and release the spirit annually so that consumers can experience changes to the liquid over time.

But according to Ewan Morgan, national supervisor of masters of whiskey for Diageo, there's no such thing as lost barrels. "Companies never lose barrels," he says. "When you have whiskey aging in different warehouses and being used for various projects, sometimes there are leftovers. So we save the barrels for future projects and then they'll just sit and sit. The romantic in me would like to say yes, but the truth is that all of our barrels are barcoded, so we always know where they are."

What's next? Espey won't reveal where he's looking next, only hinting that he has set his sights somewhere in Europe.

"I would love to find an aged rum someday," he says. "If you find one, let me know."