After reading an article in Vanity Fair about the new Umami Burger truck that has hit the streets of Los Angeles, I decided to make the trek to one of the chain’s restaurants.

Umami Burger focuses on the taste of “umami,” a phenomenon that requires some explanation. Before coming to the restaurant, I thought umami was merely the addictive component in sushi. It’s that inexplicable, yummy aftertaste that you get in Japanese food. However, upon reading the “umami certification” sign in the window of the restaurant, curiosity struck. I learned that umami was discovered over 100 years ago and is a well-known concept in Japan. Apparently, there is an “umami board” in Japan that decides whether or not a dish can be deemed to contain the umami flavor. It is present in foods such as seaweed, bonito, fish, chicken, soybeans, and green tea, among others.

According to the web site for “Umami: The Fifth Taste” (www.umamiinfo.com), the flavor can be described as “a pleasant savory taste imparted by glutamate, a type of amino acid, and ribonucleotides, including inosinate and guanylate, which occur naturally in many foods including meat, fish, vegetables and dairy products. As the taste of umami itself is subtle and blends well with other tastes to expand and round out flavors, most people don’t recognize umami when they encounter it, but it plays an important role in making food taste delicious.” Although this sounds like a mishmash of scientific terms, it seems as though this is the only way to describe a concept like a fifth taste. If you were asked to describe “salty,” what would you say? Needless to say, the description is subpar to the tasting experience.

The ambiance at Umami Burger’s Hollywood location is casual, although the chefs obviously take their craft seriously. The menu is straightforward, but don’t expect to order any classic hamburger variations. The meat is cooked medium-rare, so ask if you prefer another preparation.

Their famous invention, the so-called “Umami Burger,” comes with no menu explanation except “Umami x 6—our signature burger also available in veggie version.” I took the plunge and ordered it anyway and I was delightfully surprised at the offering. It is a delicious burger with mushrooms, cheese, and roasted tomatoes atop a wonderfully soft but crisp bun. The flavors were complex but distinct. The menu describes it as “umami x 6” because not only does the combination of ingredients in the burger taste of umami, but every ingredient is also umami-rich.

The other options on the menu are more unorthodox. My dining companion ordered the “Spanish burger,” which is made up of ground lamb, saffron aioli, and roasted peppers. I liked it a lot but favored my own choice.

As a side dish we ordered the sweet potato fries, which came with a dipping sauce (also used as a spread on the burger) that tasted of umami. The sweet potato fries were tasty, but unusually sprinkled with sugar. The sauce wasn’t thick enough for dipping but had the right taste. Based on what other people ordered, it seemed that plates of large, rectangular fries stacked Jenga-style were the most popular.

The prices were reasonable, but the burgers were small enough that two orders would be necessary to satisfy some appetites. If you’re into beer, there’s a large menu as well.

Umami Burger has four locations, plus the new truck. I visited the location at 4655 Hollywood Blvd.