Shake Shack Confidential! Hungry Hipsters Go Burp!

It was 95.9 degrees inside the Shake Shack, and my glasses were covered by a thin film of grease from standing close to the Fry-o-lator. I was spending a few days inside the Shack to get to the bottom of why 1,400 people had been lining up over the course of a day in the southeast corner of leafy Madison Square Park—and often waiting as long as 30 to 40 minutes—to purchase burgers and fries and shakes. And even though the daytime temperatures had dipped and summer was a bittersweet memory, still, they kept coming.

Were the salty little burgers made of sirloin and brisket really that good? Did piously waiting half an hour for a milkshake somehow lessen the guilt of drinking it? Or was it the Shake Shack’s deft combination of kitsch (evoking, all at once, the greasy clam shacks, roadside burger stands and county-fair midways of one’s youth) and glitz (owned and staffed by Danny Meyer, 47-year-old guru of Union Square Cafe, Gramercy Tavern and other tony spots) that drew the crowd?

Mostly, of course, I suspected that it was the shakes themselves—sublimely thick, with none of the watery disappointment or icky aftertaste of your typical New York diner milkshake. And at $4 a shake, they still cost less than the $5 shakes John Travolta and Uma Thurman made famous in Pulp Fiction.

“I think what fast food has really preyed on is a desire on a lot of people’s part to devour as many calories as possible, as quickly as possible and as inexpensively as possible,” said Mr. Meyer from his office on the east side of Union Square. “You don’t go to a fast-food restaurant for the experience of being at a fast-food restaurant. You don’t go to a fast-food restaurant for the experience of being with other people. You go there to get it cheap and get it quickly. I think what Shake Shack is tapping into is the history of these roadside stands—which actually were the antecedent of these fast-food restaurants. But it’s also atmospheric. And it feels good to be with other people.”

When I waited on line, and watched other people wait on line, I was puzzled by the fact that no one seemed to be twitching with impatience or huffing about the wait. It seemed so un–New York.

As one customer pointed out, the act of waiting on the line is part of the pleasure (what else explains the two Israeli tourists who endured a 10-plus-minute line only to order a regular lemonade and a large Diet Coke?). There is something about the process that requires a certain kind of deep, almost yogic breath. Sure, you can get your burger and shake to go, but there’s no way to get around the people-watching and the anticipation. (Plus, they don’t do delivery.)

“Work can be an impatient place,” explained Brenn Jones, 31, a wispy editor at McGraw-Hill waiting on line. “Here, you’re forced to relax.”

And, of course, in a city where people are particular about every meal, waiting on line for a burger and a shake can seem almost reasonable. When Mr. Meyer opened a hot-dog stand—the Shack’s predecessor—in the park in the summer of 2001, the line was sometimes 70 people deep.

“About a month ago, it occurred to me that I’d never had a conversation about the Shake Shack where the line didn’t come up,” Mr. Meyer said. One night he Googled “Shake Shack line” and got about 70,000 results. “People seem to actually enjoy the experience of meeting people on that line,” he said. And it doesn’t end at lunch: The Shack is open till 11 p.m.

“I had some guy come up to me the other night,” Mr. Meyer continued. “The line was all the way to 23rd Street. He said, ‘We’re thinking about trying to do a business-school study on what is the secret of the Shake Shack.’” He paused. “I just don’t think there’s a magic bullet.”

Meanwhile, one afternoon after I had been making some shakes and was resting outside, a man in Easy Rider sunglasses with the top three buttons on his linen shirt agape approached to ask if I was a manager. (I was still wearing my apron.) He told me he was starting his own burger spot—to be called Good Burger—and wanted to know if I was interested in moving to help manage his joint. He was there doing recon, he explained.

“Nobody wants to go into McDonald’s and get a burger anymore,” he said. “That’s why these places are so busy.” His name was Nick Tsoulos, and he said he was part-owner of Avra Estiatorio on East 48th Street and the Patsy’s Pizzeria chain. (Mr. Tsoulos lost a copyright-infringement case to the famous Patsy’s Italian Restaurant on West 56th Street when his pizza chain tried to enter the marinara-sauce market.)

Inside the 565-square-foot shack, a staff of between nine and 11 mans the kitchen’s seven stations. The first thing I noticed was that no one pauses to answer a cell phone or fix their hair. And it’s noisy: There’s the sloshy sizzle of patties on the griddle, the chomp of a stapler attaching receipts to food trays, the heavy tumble of ice, the buzz of the Hamilton Beach shake machine, the dull whirr of the grill hood, murmurs of “Behind!”—compressed kitchen-speak for “Watch your back.”

Carla Lalli Music, the Shack’s exotically named general manager, who worked in the three-star Union Pacific kitchen before she became Rocco DiSpirito’s second-in-command, said the pace is much faster at the Shack than at the high-end restaurants where she’s worked. In a restaurant, you first “call an order”—which means start cooking—and then, when you want it, you tell the cook to “fire it.”

“Everything here is ‘order-fire’—it immediately goes out the door,” she said.

“If you weren’t into it, you just wouldn’t last,” explained Bonnie Bucknell, a staffer who has been there since the beginning. “It’s like organic chem: It separates the men from the boys. Either you’re going on to med school or you’re going to become an English major. That was the definer. If you’re not going to stick it out, you’re not going to work here.”

The hot stations—grill and bun-fry—seemed the most intimidating to me, but not everyone agreed.

“I used to say that until I started working custard,” said Adrain Gallard, who typically works bun-fry or grill, with a shake of his head. “And I was like, ‘Wow—custard really kicks you in the rear. You got to be on your balls working custard.’”

“There’s an adversity factor to working at the Shack,” said Mr. Meyer. “It’s like a sport; there’s an athleticism required. You’re a team. It’s almost like surfing: There’s just wave after wave after wave after wave.”

This seemed particularly accurate on one muggy afternoon, when Vernon Patterson, an energetic manager, cheered, coach-like: “Keep that hydration going!”

“You hydrated?” he called out to a staffer working the Fry-o-lator, coming over to hand him a bottle of Saratoga water. “Water, water, drink water.”

So-called “expeditors” call out orders and then pass them along to diners. “Walking in I got two plain burgers” is an order for two plain burgers. Or “Shack, Double Shack.” “Shack Burger, Shack, three Shacks.”

There’s not much time for chitchat, but a curly-haired 23-year-old named April Barrios had a sweet, familiar way of calling out her orders.

“Can I get a grilled hot dog, Tayra, my sweet thing, my darling?” she called out coyly. “Who’s on the grill, Efren? You’re cooking for me, right? That’s how I like it.

“All right, Adrain, I want three ’Shrooms, and walking in, Efren, one plain burger—Tayra, can I get a Windy Wurst Mami?”

“I need a beautiful ’Shroom burger for Danny Meyer! And a beautiful Chicago Dog for Danny Meyer!” Ms. Barrios called out one day. Mr. Meyer had come in for lunch. There was no name on his ticket, just “V.I.P.”

“The Shack has always reminded me of the scene in The Wizard of Oz where the house lands on top of the Wicked Witch’s legs, said Mr. Meyer. “It’s not that there’s a Wicked Witch in the park—it’s like, ‘Where does thing come from? It doesn’t belong here!’”

I felt similarly about the staff, who were clearly not your typical burger-flippers.

“Truffles I like even, though they’re kind of fancy—cremini, portabellos … oysters are pretty good,” grill cook Efren Reyes told me, scraping the gristle off the griddle. Mr. Reyes, 6-foot-1 and with “P” and “R” (for “Puerto Rico”) tattooed on his elbows in sprawling Gothic letters, seemed like an unlikely mushroom connoisseur. He clenched a patty between his palms, then pounded it onto the griddle. The fat crackled like Pop Rocks.

Before starting at the Shack when it first opened, Mr. Reyes was a line cook at Eleven Madison Park, Mr. Meyer’s dramatic French-American restaurant in the Art Deco MetLife building annex, preparing foie gras, black cod and rib-eye steaks.

To his right, the guy manning the bun-fry station, Mr. Gallard, said he’d recently seen an episode of Iron Chef that had featured lobster mushrooms, shiitakes and truffles.

“Not too much taste in the lobster mushroom,” he sniffed, rustling the Fry-o-lator.

“You find them in the farmers’ market in Union Square,” Mr. Reyes replied. He flipped some patties. “I like trumpet mushrooms. Chanterelles are good, too.”

Meanwhile, over at custard was Ms. Bucknell, a petite French Culinary Institute graduate with a magenta streak in her hair. And Ms. Lalli Music had worked as an editor at Grove/Atlantic before she went to culinary school. Mr. Patterson was manager at Union Square Café and Tabla.

Not that everyone here is a foodie: One of the Shake Shack’s runners—who hauls supplies from the prep kitchen across the street into the Shack—squinted out into the crowd one day: “Always busy—you can’t believe this place, I tell you. Wow. I don’t understand all these people come over here and you see the Dunkin’ Donuts, McDonald’s across the corner.”

A few days later, an e-mail arrived at my desk. Starting Oct. 17, the Shack will be serving breakfast.