Even the chief executive of Buffalo Trace, Mark Brown, is out of luck. “I was in a steakhouse in Louisville Monday night which had three bottles of the 23-year-old locked in a display cabinet,” he said. “I had guests who were dying to try it, but they wouldn’t sell me any. They said, ‘No, this is just part of our stash.’ ”

Unlike most Kentucky bourbon that is made from corn, rye and malted barley, Van Winkle substitutes wheat for rye. The taste is softer and milder and allows for longer aging, connoisseurs say. The Van Winkle brand includes bourbons aged 10, 12, 15, 20 and 23 years, with the younger ones more moderately priced: Old Rip Van Winkle 10 Year sells for about $39 in stores.

But it is the 20-year-old Pappy that has a cult following like a 99-point California cabernet. “The nose is intensely fruited but also bears a tantalizing citrus zest note,” according to Wine Enthusiast magazine. “The body is huge and almost chewable and the palate is tremendously buttery with some sherry notes, a dash of dried fruits and some rich, creamy vanilla. The finish is long and elegant.”

If bourbon was once a mass-market drink, a humble Southern favorite that provided the kick in Manhattans and mint juleps on Kentucky Derby Day, artisanal small-batch bourbons have caught fire as urban drinkers pushed past Scotch and hip locavores sought out high-quality products.

Bourbon sales by distillers exceeded $2.2 billion last year, up from $1.3 billion in 2003, a boom driven by high-end brands, according to the Distilled Spirits Council. Foreign sales have also been on a tear as drinkers in Europe and Asia discover the quintessential American whiskey.

“We opened our first bourbon bar 13 years ago,” said Mr. Thomas, who in addition to a restaurant owns two bars named Bourbon in Washington. “I would never have thought I’d sell a bourbon for $75.”

“Pappy” is named for Julian P. Van Winkle Sr., whose roots in the bourbon business date to the late 1800s. He made the brands Old Fitzgerald and Rebel Yell. In 2002, the third and fourth generations of the Van Winkle family formed a partnership with Buffalo Trace, a sprawling operation on the Kentucky River where whiskey has been made for more than 200 years. It was the first to commercially market a single-barrel bourbon — one not blended from different batches — in 1984 when it introduced Blanton’s.