Seeing that your tongue detects only a few different flavor types, it seems odd that we can distinguish between a roast beef and a rutabaga (never mind between different vintages of Zinfandel).
A good part of this disparity is thanks to your nose’s chemical-sensing abilities. As you eat, volatile chemicals stream off the food in your mouth, rise through the back of your throat, enter your nasal cavity, and arrive at the same odor detectors you saw on page 124. These detectors work in conjunction with the primary tasting ability of your tongue to generate endless variations of flavor. In fact, some studies suggest that the tongue is a bit player in the sensation of taste, and that 80 percent of taste takes place in your nasal cavity.
For many years, food scientists thought the interplay between tongue and nose was the whole story behind taste. However, more recent research shows that taste involves an impossibly complex mix of factors:
• Texture. The feel of food as it gives way to your teeth and mixes in your mouth changes how you feel about it. For example, study participants rank a thick cheese sauce as tasting cheesier, even if extra flour is the only difference. And if you doubt the power of texture, try putting some hot, crispy french fries in a plastic bag for a few minutes, then see if you feel the same way about the identically flavored soggy sticks that emerge. Or compare the sweetness of a fizzy drink with an identical one that went flat half an hour ago.
• Temperature. Hot food is tastier because its volatile chemicals are more likely to drift to your nasal cavity and trigger different odor receptors. However, even without this factor, the temperature of food influences your overall experience. Think, for example, how soup warms your stomach, and why you’ll never mistake a spoonful of ice cream for butter or yogurt.
• Touch (or pain). Some sensations that happen on the tongue have nothing to do with your taste buds. Examples include the tingle of alcohol, the coolness of mint, and the sear of hot spices. These compounds mess with the other nerve endings in your tongue, and some, like hot chile peppers, actually cause pain. (Chile-pepper survival advice: Because the active ingredient is an oil, water does little to wash it away. The fat in whole milk or the alcolhol in beer dissolve it more easily. By comparison, the singe of mustard and wasabi is shorter-lived because most of its kick comes from the odor receptors in the nasal cavity.)
• Appearance. Cooks are taught that the first bite is with the eye, and there’s a solid body of science that suggests they’re right. Just changing the color of foods causes people to imagine different tastes. For example, study participants will stubbornly describe orange-flavored, yellow-colored Jell-O as tasting like pineapples. A similar effect has been noticed with white wine that’s dyed red.
• Combinations. When you pair different flavors, the result is more than the sum of its parts. For example, tasters may claim a strawberry tastes more strongly like strawberries when it’s diluted with water and sweetened with sugar.
• Expectations. There’s a reason that food tastes better when you dine at a fine restaurant. The framework of assumptions and expectations you have when you approach a meal conditions your brain to perceive it in a certain way. Current emotions and past experiences are particularly powerful: from fond childhood memories of Grandma’s apple pie to the time you projectile vomited mint-chocolate ice cream on the Tilt-A-Whirl.
In short, your perception of flavor relies on all your senses, your memories, and your current state of mind. It’s one of your body’s great surprises: A simple sense that seems to involve little more than a few bumps on your tongue just might be your body’s strangest door of perception.
Source of Information : Oreilly - Your Body Missing Manual