What's the Deal with Taste, Anyway?
Posted by miles on 2005-02-21 01:21:14
[The Pedestrian Wine Drinker]
|Taste is an interesting sense. In many ways, it's the weakest sense. You can see an almost infinite variety of items, differing in shape, color, degrees of brightness, etc. You can hear a wide range of tones, qualities, and volumes. You can distinguish thousands of smells, and touch includes dimensions such as pressure, pain, and temperature that can combine into sensations as varied as burning your hand on the stove, getting goosebumps, enoying a hot-oil massage, or being scratched by an itchy sweater. And all of these four senses are keeping you actively engaged with the outside world pretty much any time you're awake (and some when you're asleep).|
Taste, on the other hand, is more limited as senses go. It generally only comes into play when we eat, or something otherwise enters our mouths (the end of a pencil, a cut finger, a pipe stem). Researchers tell us that we can really only identify 4 basic tastes—sweet, sour, salty, and bitter—unless you also count the newly-recognized flavor called umami, a savory protein flavor found in some meats, cheeses, and particularly MSG. Flavors seem more complex because they are usually some specific proportional combination of these four flavors, and also because what we call "flavor" is usually an overall impression that includes taste, smell, texture, temperature, and mouth feel, and probably a few more subtle qualities as well, such as the actual pain caused by hot, spicy foods. But the basic mechanics of taste itself still boil down those four simple tastes.
Taste is a way of detecting chemical messages about your food. You're attracted to tastes that are associated with good, healthy foods (from an evolutionary standpoint) and find tastes that are associated with dangerous foods unpleasant. When you're a baby, this is particularly important, since your primary jobs as a newborn are to eat, grow, and fill those diapers. Though your other senses are reasonably well-developed early on, taste is the one that's the key to your future success as a human being. Suckle freely, and you'll grow; reject the breast and its life-giving milk, and you'll die, has been the case for most of human history. So it's no accident that babies prefer the sweet taste of mother's milk (mmm, lactose!) and will reject bitter or sour flavors. Their tiny taste buds are telling them what's good for them. This heightened importance of taste early on may perhaps explain why, when they get a little older, a baby that can handle an object will pop it right into its mouth.A baby's mouth has more developed nerves and muscles at birth than its hands or eyes. This may make the mouth a better choice for an infant wanting to explore the world—and why is that mouth so developed? I'm guessing it has something to do with the need for taste.
For earlier humans, taste provided a quick and easy way to find the best foods. Sweetness signaled the best-quality foods: mother's milk, fruit, honey, ripe vegetables, all good for providing energy. Umami, a protein taste, presumably helped our hunter-gatherer ancestors to appreciate and seek out the more protein-filled root. The craving for salt is not just for humans; all animals need it and crave it when deprived of it. It makes sense, when you realize that sodium is half of the chemical interaction that allows nerves to work. Predators can get some salt from their prey, but herbivores and omnivores (like early humans) need additional salt to keep healthy. So, the tastes for sweet and salt helped us to find good foods and necessary nutrients. Unfortunately for us modern humans, we continue to love these flavors even when we get more than we need of them. Loving sweets works very well when the worst thing you can fill up on is ripe fruit in season, and craving salt causes no problems when salt is primarily a trace element in other foods. Now that we can have large quantities of sugar and salt in everything we eat, we tend to do just that, and our waistlines and blood pressure suffer the results.
What about the other tastes, sour and bitter? Bitter is easy; many poisonous substances have a bitter flavor. (So do medicines, most of which are, after all, poison if you take too much of them.) Our ability to taste bitter flavors helps to keep us from wolfing down poisonous plants, at least after the first taste. Yet because we can taste it, some cultures and people develop a taste for small quantities of bitterness. How else to explain the existence of bitters and bitter liquors, like Campari, or the eventual acceptance of slightly bitter vegetables, like brussels sprouts or turnip greens?
Sour tastes, on the other hand, reveal acids. It's less clear how the ability to detect acidity provided some advantage for early humans that made sour tasting a skill worth keeping. Perhaps an appreciation for sour tastes allowed humans to take advantage of less-ripe, less-sweet fruits when they were available. Perhaps high levels of acidity (and sourness), which can be hard on the stomach, tend to be avoided more than lower levels. Children, whose stomachs can be less picky, have been shown to have more preference than adults for sour tastes (thus the popularity of extra-sour candy). It probably didn't hurt that one of the earliest forms of food preservation, fermentation, often creates sour tastes. Our appreciation for sour foods may have increased simply because we tasted it so often, from the earliest civilizations on down.
What's interesting about taste is that it's such a simple thing. Four basic flavors combine with other sensory input, with textures and temperatures and smells, to create the incredible smorgasbord of tastes we enjoy (or sometimes just experience). A straightforward way of ensuring that babies drink milk, older kids spit out poisonous plants and brussels sprouts, and adults take advantage of the high-energy foods they need to slay mammoths develops into a daily source of pleasure and invention. Tasting is a pretty cool thing, even when you're tasting something besides wine.
Next week: Tasting wine, at long last.