I recently attended a talk at UCLA about our perception of food. At the entrance we were all given little bags of jelly beans of different flavors for what ended up being an fascinating demonstration. The speaker discussed the five basic tastes we feel on our tongue – salty, sweet, sour, bitter, and umami (savory). Other “tastes” that we feel on our tongue are heat (e.g. from cayenne pepper) or coolness (e.g., mint), but technically these are through a different mechanism called chemesthesis, and are felt our tongue, and to a lesser degree also on any skin surface. “Flavor”, on the other hand, is a result of the scent of the food. Following this explanation there came a demonstration:
We were asked to pinch our nose shut with our fingers, to put one of the jelly beans in our mouth and to chew on it. Uniformly, what we felt was that the jelly bean was sweet, but not much more. We were then asked to let go of our nose, so air could go through and we could feel the scent. Suddenly the flavor of the jelly bean – coconut, strawberry, licorice - came alive. And it came alive in our mouth, not in our nose. What had been just sweet suddenly had a flavor. This is an easy experiment to try for yourself, and it’s amazing.
In cooking, salt, sugar, acid (vinegar or lemon juice), and spiciness are known as flavor enhancers. That is, they don’t actually create the flavor, they simply enhance it. So a dish without salt or sugar is perceived as being bland, even if it is well flavored. As the speaker was talking, the explanation for these characteristics suddenly became clear in my mind. When our tongue feels the taste of saltiness, sweetness, sourness, or heat of a dish, the scent is accentuated, and we perceive flavor. So the real differentiator, the thing that makes one dish taste different from the other, is its scent.
Another surprising point the speaker made was that while the perception of taste is innate, the perception of flavor is learned. We’re born with a certain perception of the five basic tastes, and that perception is not fundamentally altered over our lifetime. But our perception of different flavors is. The prime example, one which almost everyone has experienced at some point, is of eating something, and afterwards being very ill. Whether or not there was a relation between that flavor and the illness, we associate the two, and reject the flavor. I had this experience with gnocchi when I was 11 years old. I ate gnocchi in the evening, then was violently ill all night. It turned out that a stomach virus had been circulating, but for years, until my 30’s, seeing, smelling, or even thinking of gnocchi, made me feel ill. Conversely, most of us develop an affinity for flavors that we grew up with. Those affinities and preferences are learned. I have a particular love of Mediterranean food, particularly of the Lebanese, Syrian, and North African variety, and I realize that this love is not something I was born with, but rather something that I developed during a childhood experiencing these flavors.
A final interesting factoid: The speaker mentioned, as I’d heard before, that it’s believed that bitterness is one of the five basic tastes because it’s a strong indicator of danger – bitterness is often associated with poisons. So our innate ability to perceive bitterness is protective. But interestingly, for most of us, a little bit of bitterness makes food more interesting. Hence many drinks are enhanced by some bitterness, and the same is true of food. One of the attractions of eggplant (at least for eggplant lovers like myself), is its slight bitterness. Perhaps in the same way that we enjoy the thrill of (mild) danger - a roller coaster ride, surfing, driving fast - we also enjoy a little bit of bitterness. Danger is exciting.