I hate liver--how can anyone eat the stuff? But I love beets, so why doesn’t everyone else like them? Food likes and dislikes of this sort have long intrigued me, and I’ve recently found myself wondering about wine preferences as well. How is it that you might savor the gum-numbing acidity of a certain youthful Sauvignon Blanc more than I do, while I am fond of a charming Zinfandel that you claim is too alcoholic, too fruity, too whatever?
Some of the reasons people have different reactions to the taste of things clearly have to do with experience. Many wine consumers, for example, evolve over time from sweet and soft high-octane wines (remember Matteus?) to dry, tannic reds as they become more familiar with different wine styles and flavors. A lot of individual taste preferences are also influenced by our various psychological approaches: How open (or closed) is your mind when it comes to evaluating an unfamiliar taste? And genetics, we’ve now learned, also play a significant role in how we perceive taste and smell.
Along with vision and hearing, taste and smell are critical aspects of human existence, but while the mechanics of how we hear and see things have been known for a long time the science of taste and smell has only recently been studied seriously. Since I spend a good portion of my life tasting (and drinking) wine, as well as developing recipes and cooking (and eating) a fairly broad range of different kinds of food, I am particularly curious about how the chemistry of food and drink translates into taste. To learn more about all this, I recently went to Philadelphia, where I spent a day at the Monell Center.
Founded forty-five years ago, Monell is the world’s only independent, non-profit scientific institute dedicated to basic research into the senses of taste and smell.
Monell’s interdisciplinary research scientists explore a wide range of topics focusing on such things as how we use our chemical senses to understand our surrounding environment, and the effect taste perception may have on nutrition and health. Sadly, wine tasting is not included in Monell’s investigations, most likely because funding for such research has not yet come their way (hello, Gallo; are you listening, Constellation?) But since many of Monell’s projects shed light on the deeper mysteries of how we relate to aromas and flavors in general, much of the information can be applied to wine tasting.
Consider, for example, the fact that our olfactory senses develop reduced awareness of a specific stimulus, whether the smell be pleasant (the way the scent of perfume on a person’s skin quickly fades) or unpleasant (trash collectors become “immune” to the smell of garbage). Sensory adaptation, the unique process that involves decreasing sensitivity to a stimulus, affects how we evaluate wine as taste buds quickly acclimate to textures and flavors.
Olfaction and taste are more susceptible to this phenomenon than any of our other senses (vision, hearing, touch). With vision, for instance, we understand how the eye adapts to light or dark conditions via changes in pupil size, changes in sensitivity to rods and cones of light and so on. But the process of exactly how olfaction and taste adapt to a stimulus--wine, for example--is still poorly understood.
This phenomenon is especially apparent to those of us who judge wine at competitions, where we inevitably suffer from “palate fatigue” after tasting, say, 60 different Cabernets. Anyone who tells you that his, or her, taste buds are still doing their job as acutely as they were at the beginning of that flight of cabs is either in a state of blissful denial or is lying. In a scenario such as this everyone’s sense of taste and smell becomes at least somewhat desensitized no matter how much bread, water, or roast beef is used to “cleanse” or reenergize one’s palate. (Interestingly, in one Monell experiment, when the subjects’ olfactory perception had adapted so that they could barely detect the odor to which they were being exposed, the scientist presented the same odor in a different container--which the subjects reported smelling at its original intensity!)
One important area of research at Monell is anosmia, the loss of ability to smell, and therefore taste. I’ve had a personal interest in this since I once spent a terrifying couple of days with anosmia induced by zinc tablets. A friend and fellow wine writer temporarily lost his sense of taste after eating imported Chinese pine nuts. Anosmia can be caused by many things, from respiratory viral damage to toxin exposure. Loss of smell is often associated with aging and neurodegenerative diseases including Alzheimer’s and Parkinson’s. And some unlucky people are simply born without a sense of smell. According to the NIH, approximately one to two percent of the population lacks a sense of smell, but as no routine assessment of smell function exists, the percentage is likely higher. Despite the prevalence of anosmia there is very little understanding of its underlying biological mechanisms.
The many things I experienced during my visit to Monell included sampling the taste of pure calcium (harsh and bitter). I learned something about individual differences in sensitivity to sour, salty and sweet tastes (did you know that cats have no taste receptors for sweetness?). Bitter taste, I was told, can be viewed as a mutual evolutionary interaction between plants that generally prefer not to be eaten and animals that do not want to be poisoned. I learned that because senses of taste and smell change across a person’s lifespan, the changes in these receptor cells can provide important insights about cellular differentiation, growth and regeneration (Monell scientists utilize olfactory receptor cells to model changes in the central nervous system associated with aging and neurodegenerative disease).
One of the areas of research that was most interesting to hear about is the emerging knowledge of the complex processes that govern the structure and function of chemosensory receptor cells which will provide great insight not only into health-related problems, but also into individual differences in sensory perceptions. Will this help us understand why some wine drinkers tolerate highly acidic wines, I wonder? Or explain why some people like delicate, subtle wines while others seek out wines with big, bold, fruit-forward flavors? Until more answers are in, however, I’m happy to accept Monell scientist Mike Tordoff’s summation of taste preferences. “We all taste things differently,” he told me. “No two people taste the same things.”