Do certain physiological traits make some wine critics better than others? In a three-part series this week, Mike Steinberger examines the physiology of the oenophile. In Part I, he examined the age-old stoner's question: Do you taste what I taste? In this part, he set out to discover whether or not he's a "supertaster." And in Part III, he examined whether being a supertaster helps you evaluate wine.
At a Masters of Wine symposium held in Napa last year, attendees were given the same bitterness taste test that the Monell Chemical Senses Center's Dr. Charles Wysocki would later give to me. The British wine writer and Master of Wine Jancis Robinson found the PROP-soaked blotting paper to be oppressively bitter, which suggested she might be a supertaster. She subsequently reported this finding on her Web site; one e-mailed link led to another, and within days, the critic Robert Parker, though dismissive of the notion that biology can account for differences in taste, was trumpeting his dislike of spicy foods (supposedly a common trait in supertasters), and New York Sun columnist Matt Kramer was skewering the whole idea. Oenophiles were left wondering what all this talk of supertasters and nontasters was about. I was certainly curious. Had science finally proved that some people were more naturally gifted at tasting wine than others? More importantly, was I among the chosen?
The term supertaster was coined in 1991 by Linda Bartoshuk, then a professor of otolaryngology and psychology at the Yale School of Medicine. (She is now at the University of Florida.) Some 60 years earlier, Arthur L. Fox, a scientist for DuPont, had discovered that the chemical compound phenylthiocarbamide, or PTC, tasted unpleasantly bitter to some people but elicited no response in others; the former were dubbed tasters, the latter nontasters, and the differences were put down to genetic variation. In the 1970s, concerns about the toxicity of PTC led Bartoshuk and other scientists to begin using PROP instead to test for sensitivity to bitterness. During the course of her research, Bartoshuk noticed that not all tasters reacted the same way to PROP; all of them found it bitter, but a minority found it excruciatingly so. Intrigued, she began studying the tongue anatomy of these individuals and discovered that they tended to have much denser concentrations of fungiform papillae—the structures at the end of the tongue that house our taste buds—than other tasters and nontasters. Nor were they sensitive only to bitterness; they seemed to experience much more heightened taste sensations in general. Bartoshuk and her Yale colleagues began to refer to these individuals as supertasters, a name that clearly implied that these people possessed not just sensitive palates, but superior ones.
As a result, when Wysocki gave me my PROP test, I was actually quite pleased when I felt that nauseating wave of bitterness wash across my tongue. It seemed to indicate that I too might be a supertaster, which sounded like a nice credential for a wine writer. But extreme PROP sensitivity is just one part of the supertaster equation, and I was curious to find out how I measured up in the fungiform papillae department.
I was also hoping to learn more about what I had come to regard as my Achilles' heel as a wine writer/critic: my aversion to sweetness. I like dessert wines well enough, but I find the sweetness in many nominally dry New World wines off-putting. More generally, I was curious to find out if my wine preferences—I am a Burgundy fan, with a strong predilection for wines that sit at the lighter, more delicate end of the spectrum—could somehow be accounted for biologically.
Wysocki's colleague, the geneticist Danielle Reed, agreed to inspect my tongue. Not only that: She told me that she actually could test my genotype to determine if I had one or both of the dominant alleles associated with supertasting. Three years ago, researchers at long last confirmed Arthur Fox's hunch and identified the gene responsible for PROP/PTC sensitivity. It is believed that most supertasters possess the two dominant alleles for the gene, known as TAS2R38, but it is also known that some people who are highly PROP-sensitive have only one. Tasters are thought to possess at least one dominant allele, while people with two recessive alleles are categorized as nontasters. Given my strong reaction to the PROP, Reed and I took it as a given that I would have at least one dominant allele and very possibly two.
Before meeting with Reed, I had a brief chat over the phone with Bartoshuk herself. I told her about my reaction to the PROP and my low tolerance for sweetness. She said the latter was also consistent with being a supertaster; while humans, for evolutionary reasons, are disposed to like sweetness and abhor bitterness, supertasters tend to have much lower thresholds for sweetness. She told me that for nontasters—and she happens to be one—there is no such thing as too sweet; in fact, she said that she regularly adds sugar to her wine to sweeten it up. I also had a conversation with Tim Hanni, a Napa-based master of wine who has done extensive research into the science of taste—research that has convinced him that wine criticism is pretty much worthless, given how much individual palates vary. I told Hanni about my experience with the PROP, my aversion to sweetness, and my preference for lighter wines. He then asked me several rapid-fire questions: Did I like Scotch? Did I take my coffee black? Did artificial sweeteners taste different to me than regular sugar? Was I a heavy salter? Did my mother suffer a lot of morning sickness when she was pregnant with me? I didn't know the answer to the last question, but the (emphatic) answers to the other four were no, no, yes, and yes, all of which indicated to Hanni that I was either a very sensitive taster or a supertaster.
I went to Philadelphia to meet with Reed, a playfully gruff woman who seemed bemused by my interest in this topic. (In an e-mail several days later, she would write, "Why is objective testing, e.g., genotyping, important to validate what people say they experience about the flavor of wine? We don't ask music critics to take hearing tests.") She first handed me a cotton swab and instructed me to rub it vigorously against the inside of one of my cheeks. This was the genotype test; as soon as I was done, Reed's assistant, Fujiko Duke, whisked the sample to the lab. Reed then handed me a Q-tip, and told me to dab the end of my tongue with some blue food dye, which would more clearly reveal the fungiform papillae. I placed a white binder ring on the tip of my tongue, at a slight angle from the center, and Reed began counting the bumps inside the ring, which required a good minute of fairly close inspection. (Fortunately for her, I'd forgone the onion bagel that morning.) With that, we were done; I took my blue tongue home to await the results.
Reed e-mailed them the next afternoon, and they were surprising. To begin with, I had, by her count, 64 fungiform papillae per square centimeter, which is almost exactly average. This meant I wasn't a supertaster, and put me squarely in the middle of the taster range. Then came the shocker: The swab test indicated that I have the two recessive alleles—that I am, genetically, a nontaster. This result didn't square with my pained response to the PROP test, and Reed seemed taken aback. She immediately called Wysocki to confirm that he had indeed given me the PROP test. She then informed me that the taster-nontaster split was not quite as black-and-white as portrayed: Around 5 percent of nontasters can actually detect PROP, she said, and it appeared that I was a member of this exclusive club. However, my extreme aversion to the PROP was somewhat unusual and would require further investigation, so she summoned me back to Philadelphia.
So now I was a nontaster who … could taste, and apparently with enough clarity and intensity to know that I never wanted the taste of PROP in my mouth again. Not only that: I was a nontaster with the preferences of a supertaster—I was a dog that had somehow come to behave like a cat. On the one hand, I was pleased to discover that I was something of an oddball; I had visions of being dubbed Subject X and having my biology-defying palate written about in scientific journals. On the other hand, it occurred to me that owning up to my nontaster status might not be the wisest career move—who would take wine advice from a nontaster?
When I returned to Reed's office to determine if I was truly a freak of nature, the mystery was quickly settled. Reed handed me a tray holding eight plastic cups, each one containing a clear liquid. Some contained PROP-infused water, the others water alone; my job was to identify the cups with PROP. I took a big sip of the first cup, then sloshed the liquid around my mouth. By the third or fourth cup, I noticed a bitter taste in my mouth, but I had no idea which cup, or cups, was responsible. I eventually separated the cups, but it was pure guesswork. Reed then gave me the same test, using PTC-infused water. I still tasted bitterness, but I couldn't tell whether or not I was tasting the lingering effects of the previous tray. Once again, I resorted to guesswork. As I struggled to distinguish the indistinguishable, I felt like a blind man in an alley—or an inebriated wine critic fumbling for his notebook.
So there it was: I was a nontaster who could taste PROP, but with little clarity or intensity at lower concentrations. (As for PTC, Reed told me that nontasters are incapable of detecting it at any level; thus, it was likely the residual effects of the PROP that accounted for the bitterness I experienced while tasting the cups with PTC.) But why had I reacted so strongly to Wysocki's PROP strip? "You're just fussy," she said. "A fussy nontaster" (there's apparently no scientific name). As we chatted, a colleague of Reed's walked past her office. She called him in and asked if he was a taster or a nontaster. He said that he was a taster, whereupon she handed him a plastic cup containing a clear solution and asked him to splash it around his mouth. As soon as he did, he grimaced and shuddered. That, said Reed, is how a medium taster reacts to the PROP-infused cups that I had just tried.
Reed wasn't quite done with me. She then had me taste a light blue liquid. Suddenly I was the one grimacing and shuddering; it was grotesquely sweet, and casting aside my manners, I dashed over to her trash bin and spit it out. "Jesus, what the hell was that?" I asked Reed, who was laughing. It was Kool-Aid, spiked with three times the recommended sucrose level. She told me that I was the first person ever to spit it out; most people reacted indifferently, and some complained that it was not sweet enough. I told her I wasn't kidding when I said I had a low threshold for sweetness. Reed, herself a nontaster, took my cup and drank the rest of the Kool-Aid. "Quite lovely, actually," she said.