Thursday, November 22, 2007

The taste of wine, part 1

Now it’s time to put the wine in your mouth. Whereas sniffing wine involves just the nose, putting it in your mouth involves input from both the tastebuds on your tongue and also the smell receptors in the back of your nose. Thus the sensation is a combined one.

There are five basic tastes: bitter, salty, sweet, sour and umami. [The last one may need some explanation: umami refers to the sense of deliciousness or savouriness we experience when we taste the amino acid glutamate, which is a component of proteins. Apparently, some wines have this umami flavour. It’s a recent addition to the tastebud repertoire in that until a few years ago we didn’t know about it.]

Now these five basic tastes, in terms of information about what is in our mouths, are rather basic. Think of them as the lines in a child’s colouring book. The colour is added by the smell receptors in the nose, which are activated when volatile components of what’s in our mouth travel through to the nasal cavity from the back of our mouths.

For this reason, when we are tasting wine we swish it around in our mouths a bit, or do a sort of closed mouth chew. Some people take air in as they are doing this, but it’s noisy and I find it really annoying at wine tastings when I hear it because it’s kind of ostentatious and a bit pretentious, I reckon. And it sounds disgusting. [End of mini-rant.]

One more thing to add about taste, while I’m in nerdy mood. It’s about the tongue taste map. You may have seen this in textbooks, or even wine tasting books: it consists of a diagram in which the tongue is split into zones, each of which is supposed to be where one of the primary tastes is predominantly detected. Wine glass manufacturers who offer a gazillion wine glass shapes, one for each type of wine, have used this map as a part-justification for why you must have a separate glass for each wine style: they have claimed that the different glasses direct the wine to different zones of the tongue.

Well, I hate to be a party pooper, but this map is apparently a myth. Yes, different bits of the tongue are more sensitive than others, but they are more sensitive to all tastes. But the myth of the tongue map is a surprisingly enduring one: even though Professor Linda Bartoshuk of Yale University, who is a taste expert, has debunked this map on several occasions in print, you still see it around.