What's an umami burger? How do you get one?

The umami burger is served up by a four-restaurant chain in Los Angeles, which uses Japanese-style ingredients to create savory umami burger creations.

Umami Burger, southern California’s new, Japanese-flavored burger chain, is expanding with a new twist – a delicatessen dedicated to umami.

An Umamicatessen.

The umami flavor is the so-called “fifth taste” beyond sweet, sour, bitter, and salty, often referred to as savoriness or “meaty” flavor. And the Umamicatessen, due to open in Los Angeles this summer, will consist of four or five restaurants that sell food with an umami flavor. Diners will be able to eat deli food or dessert. Or, they can opt for one of the Umami burgers that started the umami craze.

Each Umami burger uses umami ingredients. The best-selling Unami Burger, for example, includes a grilled shitake mushrooms, parmesan cheese, carmelized onions, and roasted tomatoes, all umami toppings aimed at enhancing the flavor of the beef ground in-house.

Started in early 2009 by Los Angeles-based restaurateur and self-taught chef Adam Fleischman, Umami Burger has created a buzz.

GQ Magazine named it the burger of the year this past December.

The original outlet made $18 million in its first year, Mr. Fleischman told Restaurant News. The second one, expected to make $2.5 to $3 million in its first year, is nearly four times the size of the original.

The chain has grown to four restaurants in the L.A. area with a fifth one due to open soon and the Umamicatessen this summer.

The burgers don’t come cheap, however. They range from the $9 Port & Stilton burger to the $11 Truffle burger.