What is umami?

An article in the Wall Street Journal talks about Umami and how it is becoming a focal point in restaurant cooking as well as packaged goods from some well known food manufacturers like Nestle, Frito-Lay and Campbell's Soup. In the article they state that:

"Americans are taught from an early age that there are four basic tastes - sweet, salty, sour and bitter. But what describes the taste of chicken soup?

To an increasing number of chefs and food-industry insiders, the answer is "umami," dubbed "the fifth taste." First identified by a Japanese scientist a century ago, umami has long been an obscure culinary concept. Hard to describe, it is usually defined as a meaty, savory, satisfying taste."

I have been familiar with the term for a couple of years now but honestly would have been hard pressed to explain umami to someone if asked. So I turned to Google, How Stuff Works and Wikipedia to better understand this so-called fifth taste.

Umami was first identified as a taste in 1908 by Kikunae Ikeda of the Tokyo Imperial University while researching the strong flavor in seaweed broth. He found that kombu, a type of edible seaweed, had a different taste than most foods.

Ikeda that found that the high concentration of glutamate in kombu was what made it so tasty. From there, he crystallized and began commercial distribution of MSG products. Soon monosodium glutamate (MSG), the seasoning that would become popular the world over.

Umami is a Japanese word meaning "savory" or "meaty" and thus applies to the sensation of savoriness  - specifically, to the detection of glutamates, which are especially common in meats, cheese and other protein heavy foods. The action of umami receptors explains why foods treated with monosodium glutamate (MSG) often taste "heartier".