Delanceyplace.com 9/2/08-Wine Experts

In today's excerpt--there are many reasons to question the validity of various wine rating systems, such as the Parker ratings, which uses a scale to 100, and where the difference between a rating of 89 and 90 can make a huge difference in the sales of a given wine:

"Expectations affect your perception of taste. In 1963 three researchers secretly added a bit of red food color to a white wine to give it the blush of a rose. Then they asked a group of experts to rate its sweetness in comparison with the untinted wine. The experts perceived the fake rose as sweeter than the white, according to their expectation. Another group of researchers gave a group of oenology students two wine samples. Both samples contained the same white wine, but to one was added a tasteless grape anthocyanin dye that made it appear to be red wine. The students also perceived differences between the red and white corresponding to their expectations. And in a 2008 study a group of volunteers asked to rate five wines rated a bottle labeled $90 higher than another bottle labeled $10, even though the sneaky researchers had filled both bottles with the same wine. ...'

"Given all these reasons for skepticism, scientists designed ways to measure wine experts' taste discrimination directly. One method is to use a wine triangle. It is not a physical triangle but a metaphor: each expert is given three wines, two of which are identical. The mission, to choose the odd sample. In a 1990 study, the experts identified the odd sample only two-thirds of the time....

"Wine critics are conscious of all these difficulties. 'On many levels ... [the ratings system] is nonsensical,' says the editor of Wine and Spirits Magazine. And according to the former editor of Wine Enthusiast, 'The deeper you get into this the more you realize how misguided and misleading this all is.' Yet the ratings system thrives. Why? The critics found that when they attempted to encapsulate wine quality with a system of stars or simple verbal descriptors such as good or bad their opinions were unconvincing. But when they used numbers, shoppers worshipped their pronouncements. Numerical ratings, though dubious, make buyers confident."

Leonard Mlodinow, The Drunkard's Walk, How Randomness Rules Our Lives, Pantheon, Copyright 2008 by Leonard Mlodinow, 2001, pp. 132-133.