The PROP test and reactions to it

This is an article I devoted to this issue, raised back in July in the your turn archive on this site, for my syndicated column, partly inspired by reaction to what I originally wrote here.

If you see the wine professionals of your acquaintance sticking out their tongues at each other, don’t worry too much. They may simply be counting each others’ fungiform papillae. The way you do. Or at least the way wine people seem increasingly intrigued by the science of tasting, and one all-too-measurable test that tasters can take.

Professor Linda Bartoshuk of Yale University first published her ground-breaking work, dividing the population into so-called supertasters, normal tasters and non tasters, back in the 1990s but it has taken the world of wine a while to catch up with the implications. With colleagues she identified a substance called PROP (6-n-propylthiouracil, a thyroid medication) which can help identify which of us has an abnormally high or low number of taste buds (fungiform papillae) on our tongue. Roughly a quarter of the population seem genetically programmed to have a markedly high number of taste buds, about a half have an average number, and another quarter have relatively few.

Because PROP is a prescription drug and there are ethical issues concerned with exposing the public to such a test and achieving their ‘informed consent’, Bartoshuk has devised a simple physical way of measuring the density of your own taste buds. Her suggested method is to swab the front of your tongue with food colouring and then press a plastic (paper gets messy apparently) ring-binder reinforcer on to it. If you can count more than 25 coloured spots on the ring, you are a supertaster apparently. This is for reinforcement rings on sale in the US of course. If there is no international standard for reinforcement rings, you’re on your own.

I was unexpectedly given a proper PROP test at The Institute of Masters of Wine 6th Symposium held in the Napa Valley last July. The opening session was moderated by Tim Hanni MW, a Californian musician and sometime employee of Beringer who has always been particularly interested in questions of taste. It was he who first introduced many of us to the concept of umami, the fifth, monosodium glutamate-like sense we are now supposed to add to sweetness, sourness, saltiness and bitterness – although I have to say that I very rarely find it in wine.

Presumably with the full agreement of Bartoshuk’s Yale colleagues, Hanni gave out little strips of paper that had apparently been impregnated with PROP. The 250-odd of us in the room were to put these on our tongues and record whether we tasted almost unbearable bitterness, mild bitterness or nothing at all. This supposedly reliably indicates whether we are supertasters (hypertaster would be a more accurate and less emotive term), normal tasters or non (hypo) tasters. And duly, about a quarter of us fell in to one or other of the extreme categories with about a half experiencing mild bitterness and therefore classified as normal tasters.

I had always reckoned that for my job, describing and recommending wines, it would be best to be a normal taster. That way my sensitivities would most closely ally with the greatest number of my readers. I would have been a bit upset to discover I was a non taster, but I was also rather disappointed to find that my paper strip tasted horribly bitter, indicating that perhaps I was a hypertaster.

Hypertasters are supposed to be particularly sensitive not just to bitterness but to general astringency, acidity and the burning sensations generated by high alcohol and particularly spicy foods. Hanni gave us an accompanying questionnaire with questions ranging from how we felt about the taste of coffee to whether our mothers suffered badly from morning sickness. This brought more ominous news. I am not a natural coffee drinker. I do find coffee pretty bitter and tend to use it mainly and infrequently for combatting jetlag. Yes, my mother had suffered terribly from morning sickness. Both of these supposedly correlate with hypertaster status.

And apparently women are far more likely than men to be hypertasters: 35 per cent of American Caucasian females tested by Bartoshuk as opposed to 15 per cent of American Caucasian males qualified. There also seems to be a particularly high incidence of hypertasters among Asians, incidentally. Since in my experience, in very general terms, the Asian palate seems particularly refined, this was all looking as though hypertasters might constitute a crack elite of tasters.

But hang on, I thought. What we wine tasters sense on our tongues is only part, a minority part many would argue, of the wine tasting process. The single most important attribute of a wine as far as I’m concerned is not its vital statistics – how bitter, acid, astringent or alcoholic it is – but its flavour, the much more subtle characters that can be sensed only by the sense of smell rather than the sense of taste. If I am a hypertaster it could well be a huge disadvantage to me as a wine writer, making very bitter, tart, tannic, alcoholic wines seem more unattractive to me than to most of the rest of the population, but this is only part of the story. There is absolutely no suggestion that my all-important nose is any better or worse than anyone else’s.

In a brief report on the Symposium for subscribers to my website I mentioned all this en passant, thinking that they deserved to know if my palate was deformed and in what direction. As purple pagers know, one member contacted one of the Symposium speakers, Professor Michael O’Mahony, Professor of Food Science and Technology (Sensory Sciences) at Davis for more information and he replied, “The test that Tim gave does not really diagnose tasters v hypertasters. It is a lot more complicated than that and the test was completely biased. You can tell Jancis that she is probably a normal taster.”

This was good news, and I reported it here, but too late it seems. Fellow wine writers were already reacting.

Mark Squires bulletin board on started a thread on whether biology determined tasting ability, initiated by someone who seemed to understand the issues and pointed out it was quite brave of me to admit to being anything other than normal. But that misleading prefix ‘super’ does a lot of damage. Robert Parker himself jumped in early to declare that he couldn’t abide spicy food in any form. (I like it, incidentally.) Then another American wine writer, my old friend Matt Kramer, who must have read this thread (though not my own account) dashed off a column for that well-known oenophiles’ gazette the New York Sun making me the prime perpetrator of “an almost desperate attempt by some of today's wine tasting potentates to bolster their credibility by suggesting a physical superiority”.

This was the last thing I was attempting. But I do think it is as well for those of us concerned with wine – whether they are consumers of the words they write or the wines they make – to realise that people taste things in very different ways. And it is probably helpful for consumers if wine critics take the test and come clean about where they stand. Perhaps I am a hypertaster, and perhaps this explains much of what I don’t like about particularly alcoholic wines. I would say I have a good tolerance of tannin and acidity however – I really enjoy young, tannic wines and, especially, acidity. So I’m not too sure where this leaves us. It could certainly explain my apparent distaste for the new genre of controversial wines from Château Pavie in St-Emilion which are certainly chock full of everything. I would describe as them as uncomfortably exaggerated but they presumably taste just right to other palates.

Jamie Goode, in his extremely accessible book Wine Science, addresses some of these issues and asks Gary Pickering, a professor of oenology at Brock University in Canada, whether hypertasters are at an advantage when it comes to wine tasting. “I would speculate that supertasters probably enjoy wine less than the rest of us,” the professor is reported as saying. “They experience astringency, acidity, bitterness, and heat (from alcohol) more intensely, and this combination may make wine – or some wine styles – relatively unappealing.”

But if I enjoy wine less than most of the rest of you, you are very lucky wine drinkers indeed.