Almost four years ago, I posted the original Peel & Eat Kleenex: I Double Dog Dare You! story.
A couple of weeks ago, I told the story to my department chair. Being a scientist, she decided that she needed to try one. She was able to taste the citric acid (sour/lemon taste), but not the SDS (also known as sodium lauryl sulfate, which has a bitter taste). She commented that this was interesting, because she also doesn’t taste PTC. (The ability to taste PTC and other related bitter flavors is genetically inherited. Many biology teachers pass out paper soaked with PTC when they teach genetics.)
She asked me whether I was able to taste the SDS. I replied that I hadn’t tried one, but that I’m also a PTC non-taster. She pointed to the xkcd comic on my bulletin board and told me that as a scientist, I absolutely had to try one to get the data point. Sure enough, I also tasted the citric acid but not the SDS. Over the next several days, I asked the small handful of students who had also tried the tissues but didn’t seem to respond to the bitter flavor, and all of them are also genetically unable to taste PTC.
With a little digging, I found some websites that mention that the same gene is, in fact, responsible for the ability to taste both PTC and SDS. It’s been over 25 years since I took organic chemistry, but both PTC and SDS are sulfur-containing organic compounds, and I can envision a reaction with saliva that might create a similar structure in both molecules that could bind to an appropriate receptor.
Now that I’ve established that only some people can taste the SDS, and that it relates to PTC (which most of my students remember from their biology classes last year), there has been a renewed interest in tasting the tissues. This year’s count is currently 29 students, 2 teachers, and 1 administrator.
