As well all know, taste is a matter of taste... but what is "taste", exactly? In the narrower sense, we mean the "sense" of taste, i.e. direct perception on the tongue. The way in which we perceive flavour, however, results in particular from a combination of our senses of smell, taste and touch. It is the interplay of these senses that determines whether we like the taste of a given food or dish.
But what about the sense of taste in narrow terms? What is it that we taste on our tongue? We use our tongues to distinguish between five basic tastes, i.e. sweet, sour, salty, bitter and umami. The latter is created by the presence of glutamate, which is contained primarily in high-protein foods such as meat, and is also used in the kitchen as a flavour enhancer. Umami can also be described by the term "meaty". The rich diversity of taste sensations arises from the wide-ranging combinations of these five basic tastes, such as the sweet-and-sour taste we experience when we drink hot lemon with sugar.
For a long time, scientists assumed that we identify each of the basic tastes at a different point on our tongue. This would mean that we can only experience sour and salty tastes at the edge of our tongue, or sweet tastes only at the tip. This view, however, has since been disproven by subsequent research. While it is true that the edge of the tongue has more taste buds than the base and is thus more sensitive, the tongue is not divided into different types of taste. The one exception to this rule is the bitter taste, which is located chiefly at the rear of the tongue.
The taste buds are the organs in the tongue that register taste, and are located around what are known as the gustatory papillae. These are the small structures on the upper surface of our tongue. An adult has approximately 2,000 to 4,000 papillae on their tongue. Whenever we eat a salty soup or a sweet dessert, the sensory cells in the taste buds are activated and our brain is informed how salty or sweet the food is. Around half of the sensory cells respond to all five basic tastes, while the remainder specialise in a particular taste.
Our sense of taste deteriorates with age, in a development that is easy to explain. Our sensory cells have a lifespan of just 10 days, but are constantly being renewed. In advanced age, however, this renewal no longer takes place on a 1:1 basis, with result that the number of sensory cells declines over the course of time. One tip here is to make generous use of fresh herbs when seasoning your food. This enables us to continue to experience a rewarding taste experience in old age thanks to our other senses, including our sense of smell.
Despite often being referred to as such in colloquial language, "hot" is not a flavour in its own right. It is, rather, perceived through the free nerve endings of the trigeminal nerve in the mouth and throat region. These nerve endings are responsible for determining whether we find a given dish seasoned with pepper, chilli or curry unpleasant or even painful.