At Park Avenue Liquor, the phone calls from people asking about it are a steady drumbeat: “It never stops,” says vice president Jonathan Goldstein.

It’s the same story at Astor Wines & Spirits, where workers once counted nearly 50 such calls in a single day. At the Whiskey Shop in Williamsburg, the barrage of people seeking it has gone from “crazy” to “just absurd,” says owner Jonathan Wingo.

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The “it” in question is the city’s, and maybe the world’s, most sought-after tipple — Pappy Van Winkle’s bourbon (usually referred to as Van Winkle). Bottled in small amounts by the Old Rip Van Winkle Distillery of Frankfort, Ky., it’s gone in recent years from a niche item favored by a cult of bourbon connoisseurs to an object of fervor, hunted by an ever-growing number of devotees the way Paris pursued Helen of Troy.

“People treat it like gold,” says Elizabeth Mitchell, the marketing manager at Southern Wine & Spirits, the wholesale distributor. “It’s created a huge frenzy.”

That frenzy peaks in the late fall, when the larger of two annual shipments from the family-owned bourbon maker goes out to stores. In New York City, the bottles have just arrived in shops, but don’t expect to saunter into your local liquor store and find one — they never make it to the shelf.

The fever runs especially hot right now, not only because insiders know about the timing of the late-2012 release but because it’s being hunted by holiday shoppers who have read about this elusive prize and are looking to put something special under the tree.

It falls to weary store owners to tell them, over and over, that they’re flat out of luck. Whatever bottles stores manage to get their hands on go to favored customers who’ve jockeyed their way to the top of waiting lists (or in some cases to the winners of lotteries).

Other stores don’t even bother with a list: Paul Bressler, the spirits buyer at 67 Wine and Spirits on the Upper West Side, used to keep one, but it led to too much frustration, he says.

“You’d have 50 people on a waiting list, then 10 bottles come in, and you have 40 unhappy people,” says Bressler. “Everybody wants it, and nobody will accept the fact that they’re not going to get it.”

Nobody knows that better than Catherine Jones of Long Island City, who hoped to land a bottle for her boyfriend’s 29th birthday. She started researching back in February, made the list at Astor in August, then was told last week it wasn’t going to happen.

“I was very disappointed when I found out that the chances were essentially zero,” she says.

By now you’re no doubt asking: What is the deal with this stuff?

Van Winkle bourbon comes from a family business whose roots stretch back to the late 1800s. For years, the Van Winkles ran the distillery, which shut down in 1972.

The current owner, Julian Van Winkle III — grandson of founder Julian “Pappy” Van Winkle — inherited ownership of the Van Winkle label, and began buying up old stocks of “wheated” bourbon, which substitutes wheat for the rye that most bourbon contains (alongside corn and malted barley), creating a softer, sweeter profile.

Van Winkle, who runs the company along with his son Preston, blends those old stocks to create Van Winkle’s various bottlings, which are aged 10, 12, 15, 20 and 23 years, the price escalating with the age. (The current 10-year is the first whiskey distilled specifically for the Van Winkle label, rather than blended from old stock.)

Van Winkle III started selling his whiskeys in the early 1990s, to no immediate fanfare. Some sky-high critical ratings got drinkers’ attention, and demand began to grow. Still, the bourbon remained pretty well under the radar.

“Fifteen years ago you could order as much as you wanted — nobody knew about it,” says Goldstein of Park Avenue Liquor. Astor sales manager David Phillips recalls Van Winkle languishing on the shelves a mere decade ago.

Interest started to snowball several years ago, and since then it’s built steadily through word of mouth and bourbon-blog chatter. High-profile fans such as chefs David Chang and Anthony Bourdain (“the most glorious bourbon on the face of the planet,” says Bourdain) have further boosted its profile.

As demand has skyrocketed, the aged nature of the product means supply has remained the same — a relative trickle of some 7,000 cases a year. It’s created an upward spiral where as the scarcity grows, it creates more hype, which creates more scarcity, and so on. Store owners say they’re now seeing a growing number of people who know nothing about Van Winkle except that others want it.

It’s no surprise then that a bottle of Pappy can fetch a pretty penny. The distillery’s suggested prices run from $40 for the 10-year to $250 for the 23-year, with the 15-year — perhaps the most coveted by bourbon hounds — at $80. Some retailers stick to those prices, but others boost them — and still others flat-out gouge.

Boxed out by retailers, the would-be Van Winkle drinker might turn to eBay, where bottles regularly fetch $500 or more. Or they might hit the road: a favored tactic of the most determined seekers is to travel to markets where demand is relatively low.

All this demand and desire leads to an obvious question: Is Van Winkle really that good? The passion makes perfect sense to Mark Casey, who’s just finished shooting “Chasing Pappy,” a documentary about the Van Winkle cult. He lovingly describes his first encounter with the bourbon, and the way it delivered “everything I like about bourbon, only richer and more saturated.”

Some say the hype has gotten way out of hand, though.

“It’s a good bourbon, it’s not a life-changing experience,” says Bressler of 67 Wine and Spirits, who calls the clamor for the coveted hooch “bizarre. People shouldn’t want it that badly.”

Matters of hype aside, though, you’d be hard-pressed to find anyone who doesn’t agree that Van Winkle makes a hell of a good bourbon.

“For the most part, I think it is that good,” says John Hansell, editor of the Whisky Advocate. “The quality is very high.”

Meanwhile, the man in the eye of the consumer storm, Julian Van Winkle himself, was low-key when asked about the growing mania for his product — something he says is “amazing to me.”

Output will rise in the coming years, he says, though “we’re never going to make a ton of it.”

As for how to get your hands on a bottle, he says he’s often asked, but has little insider wisdom to offer, having not seen a bottle on a shelf in years: “It’s hard even for me to help people find it.”