When I look further into the subject of taste perception there is one question that keeps popping up: how does our tongue distinguishes between flavors? Off course the answer can be found in biology!
First we should take a closer look to the tongue and how receptors are able to send signals to our brain. From biology we remember that the human neurological system contains receptors. One kind of receptor is a chemoreceptor that translates chemical information into electrical impulses. Taste is perceived by the gustatory receptor cells. One taste papillae on our tongue consists of several taste buds that each contain about 50 receptor cells. The papillae are the small bumps that you feel on your tongue.
When we eat, molecules of the food mix with saliva and react with the gustatory receptor cells. These send a message (electrical impulses) to our brain (gustatory area of the cerebral cortex) and the brain translates that message into a sensation as taste.
So conclusion of this short summary is that sensations like chemical compositions of food become perceptions like taste only when they reach the brain.
Bron: http://science.howstuffworks.com/environmental/life/human-biology/taste1.htm, Dowdey, S., How taste works, A discovery company