West Coast Umami Burger has just landed in New York.

Mila Kunis hired Umami Burger to cater Ashton Kutcher’s birthday party, Taylor Swift is often seen at the Los Angeles locations, and San Francisco customers will line up for 90 minutes just to get a taste of one of their burgers.

“The water is different in New York, so our buns, which we make on-site, have been a challenge for us,” explained Brian Rosman, Umami Burger’s spokesman.

“They are a little more crinkly than we are used to, but they’re still very soft inside.”

The burgeoning burger chain will open its first New York location at 432 Sixth Avenue on Monday.

It is the first of three outposts set to open in the near future, with another location coming to Williamsburg early next year, and a third to the Financial District’s Brookfield Place soon after.

“Our customers have been asking for us to open in New York for years, but it took a while to find the perfect location,” said Brian Rosman.

Umami Burger, which aims to bring the fifth flavor, savory, to the quick-service burger, has been somewhat of an enigma for foodies on the East Coast since its launch in 2009.

The outfit, which has grown in just four short years from a $40,000 ­investment to a multimillion-dollar enterprise, quickly became famous for its list of secret, off-menu items, which vary from location to location.

Umami Burger opens its first New York location at 432 Sixth Avenue

Favorites include the Pink Slime burger, a riff on the controversy surrounding ammonia-treated beef bits used in some commercial U.S. food products, and the Dork, a duck-pork hybrid.

Ingredients are all chosen for their addictive, umami-rich flavor – shiitake mushrooms, Parmesan wafers, truffles soaked in port wine – which are carefully crafted, according to creator Adam Fleischman, to alter New Yorkers’ tired perception of what a hamburger should be.

“They are driven from culinary inspiration,” said Brian Rosman.

“We did one called the Stink burger for example, which was a combination of really stinky stuff. Garlic, fried anchovies, and cheese, to be exact.”

“The chefs are inspired by what’s happening out in the world, ingredients of the moment,” he added.

“Sometime takes two days to perfect a burger, sometimes a year, they will tinker and tinker and tinker until they get it exactly right.”

The word umami, first popularized in the early 1900s by a Tokyo scientist named Kikunae Ikeda, who invented the term and sits on the wall of Umami Burger’s restaurants, loosely translates in ­Japanese to “deliciousness”.

The “fifth” taste (the other four being sweet, sour, salty, and bitter), can be found in the tangy and faintly acidic flavor of gently cooked tomatoes, anchovies, Parmesan cheese, and soy sauce.

Aside from striving for the ultimate “umami bomb”, as Umami Burger chefs call it, the bun-to-burger ratio aims to create balance in the burger – one reason why the chain has become such a favorite.

Adam Fleischman’s beef patties, all sprinkled in his own Umami Dust, are six pounds and coarsely ground in-house, instead of ­prepacked and delivered to the restaurant in a truck.

And the Portuguese-style buns, neither too big nor too small for the Umami patty, are baked exclusively for Umami Burger, made with milk to enhance the umami flavor.

Each hamburger, featuring a very shiny bun, is plated by itself on porcelain like a fine restaurant entree, next to a selection of Umami-made toppings – the exclusive ketchup and garlic aioli were favorites.

The Hatch Burger, made with roasted green chiles, and the famous Truffle Burger were brought out alongside the restaurant’s Cheesy Totes – only available by request off the secret menu.

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