You can taste because of taste buds (receptors) on your tongue and in other areas of your mouth and throat. They function in combination with the processing of odor molecules that can enter your nose through active sniffing or breathing or enter from the back of your throat during eating. You may have noticed that when your nose is stuffed up due to a cold, your sense of taste is often altered significantly. Unimpaired, your taste buds are able to differentiate between five general taste groupings: Salt, sweet, sour, bitter, and umami. Salt (substances that contain sodium or potassium chloride). Sweet (substances such as glucose, fructose, sucrose, and aspartame). Bitter (substances such as caffeine and quinine). Sour (acidic substances such as citric acid). And Umami (substances such as monosodium glutamate or MSG). Some people prefer salty tastes, others lean toward sweet or even bitter tastes. It appears that the sensitivity of taste bud processing can alter with age. One way to help maintain the pleasure of processing of food flavors is to alternate bites of different foods. (Source)