The Story of Supertasters, the PTC Gene, and Bold Reds
Did you ever wonder why some people prefer bitter tastes and some shy away? I’m talking about grapefruit, arugula, dark chocolate, black coffee, tea and of course tannic (young and thick skinned) red wines. Well, there is a scientific reason for this preference: it depends on a gene which detects Phenylthiocarbamide (PTC), a bitter, harmless chemical. In the 1930’s a scientist at DuPont Arthur Fox spilled some PTC and a lab colleague detected a strong bitter taste from the airborne powder. Fox tasted nothing and, as scientists do, he wanted to find out why. 1, 2
The Genetic Story
After much research the bitter gene was discovered. Like many other heritable traits, the presence of the gene in your DNA depends on the genes of your parents. If you received this gene from only one parent you taste PTC a little; you would be called a medium taster. Supertasters have inherited this gene from both parents and PTC tastes “repugnant” to them. Those who did not inherit a copy of the gene from either parent are non-tasters and can’t detect the bitterness. When I learned about this concept from a tour guest from Colorado, I purchased some vials of PTC paper (similar to litmus paper) and proceeded to test myself and my husband, John (my excellent van driver and tasting companion). I am a medium taster and he is a non-taster. He described the paper slip as tasting of just paper.
The Experiment
I then brought the papers to Anne Amie Winery on a wine tour and the tasting room folks volunteered to take the PTC test. Of the 4 volunteers, two were non-tasters, one was a medium taster and one was a supertaster. The supertaster gagged and needed to wash the taste out of her mouth! Wow what a lucky sampling-I got all 3 reactions from just 4 people!
Why Does It Matter?
What does this mean and why have we evolved with this gene? Nature-wise, plants that are toxic often carry a bitter taste, which animals like us have learned to avoid. This trait selects for those with this bitter gene to survive at a higher rate than non-tasters who may unwittingly eat a toxic plant and not live to procreate. In fact, household products often are laced with Bitrex, a very bitter, but harmless compound, to deter children from inadvertently drinking laundry detergent, as well as cleaners left unsecured or repackaged into familiar bottles (like water bottles).3
The Bold Red Story
What’s the wine connection? Bitterness in wine is typically delivered by tannins contained in grape skins. Red wines spend more time macerating on their skins to extract color, flavor, polyphenols, aroma compounds and tannins (which improve ageability and reduce spoilage). Some grapes such as cabernet sauvignon, syrah, and zinfandel have thicker skins, hence higher tannin levels. White grape skins also contain tannins but spend less time on their skins during fermentation so tannin levels are lower. An exception is orange wine, which is a white grape macerated on their skins for a longer time, providing more color, flavor and tannins. Anne Amie and Beckham’s Roses of Pinot Gris can spend up to a year on their skins making a delicious white style wine with a lovely pink color and enhanced flavor.
Folks who are supertasters are especially sensitive to the bitter tannins in full bodied red wines so tend not to like them, and prefer sweeter or fruitier wines like Riesling, Gewurztraminer, dessert wines (and milk chocolate, coffee with sugar). Or, they can wait until time ages a good Cab or Syrah, which breaks down the tannins to smaller molecules and the bitterness decreases. Non-tasters tend to love high tannin wines as they taste all the flavor but none of the bitterness. Us medium tasters can go either way, appreciating a little bitterness while not being repelled by it.
What about Pinot Noir?
Pinot Noir is a thin skinned grape, so tannins are much less prevalent as opposed to a Cabernet Sauvignon and other full bodied grapes. On the other hand, this thin skin makes it much harder to farm as it is susceptible to mold, wind damage, sunburn, heat and cold. But on the bitterness scale it does not require as much aging to be drinkable, but many of the Willamette Valley Pinot Noirs age very well. Pinot Noirs just a couple of years old are very tasty, whereas 2 year-old quality cabs are best left alone for a few (or many years) to reach their peak. Use of oak barreling can tame tannins (the new oak surface reacts with the wine to speed up the breakdown of tannin molecules), and the oak flavor can mask the tannins as well.
The Takeaway
Remember, it’s not just a personal preference when it comes to bold wines; there is a scientific reason why people prefer one style over the other. No judgment please! A bold red lover does not have a “better” palate versus a sweet wine lover, just a different set of genes! There is room for all wine styles in our world. Though French Bordeaux reds (and their high tannins which take years to tame) are considered some of the best wines in the world , so are sweet white Sauternes from the same region. And we know California Cabernet Sauvignons are coveted among wine collectors, but they aren’t for everyone, especially those supertasters who can’t afford to wait 5-10-20 years! Taste for yourself and buy what you like!
The Sales Pitch
Join a Triangle Wine Country Tour and take the PTC test and see what kind of taster you are! Or if you know, let me know when you book and I’ll find the wineries and the wines you are most likely to enjoy. See you soon in the Willamette Valley—we have it all here!
(Shout out to tour guest Michele from Colorado who turned me on to this PTC gene and test!)
1 https://learn.genetics.utah.edu/content/basics/ptc/
2 https://www.winemag.com/2018/01/29/supertasters-wine-preference/
3 https://www.bitrex.com/en-us/about-bitrex/what-is-bitrex