Normally when people think of “tastes”, they think of sweet, salty, sour and bitter (“spicy”, or piquance is not a taste). However, in 1985 the family of four basic tastes were introduced to a new member: umami. Umami, commonly known as “savouriness” is a taste that has had its own word in Asian countries (e.g. 감칠맛, or gamchilmaht in Korean) for thousands of years but has not had a proper English word until very recently (much like piquance). Umami is a portmanteau of two Japanese words: うまい(umai) and 味(mi), which means “delicious” and “taste” respectively.
Sweetness comes from glucose, saltiness from sodium and sourness from acids. Then where does umami come from? Umami is the taste born from glutamates, which is found in high concentrations in meat products, thus leading to the association between umami and the taste of meat. For example, bacon is known to have six different types of umami flavours, creating a unique and addictive taste. Another product high in glutamate is monosodium glutamate, or MSG. MSG is essentially glutamate plus a sodium ion and thus brings out the full taste of umami when added to food. As umami has a powerful effect of boosting appetite and having a slightly addictive property means that chefs like putting MSG in foods to boost sales. Contrary to popular belief that MSG is detrimental to your health, recent researches have shown that unless you have an allergy to it, MSG is safe to consume even in high concentrations.