Seems this is typical of urban legends - something that has a hint of truth but which has been retold in a way to produce a more sensational sounding result. Snopes did a little digging a couple of years back to find out what the origin of this story was:
http://sciencesnopes.blogspot.cz/2013/05/about-that-wine-exp...To save you the bother of reading the article (though it is pretty interesting) here's the key few sentences which describe the experiment setup and execution. Essentially a scientist called Frédéric Brochet was doing some research into "perception and wine tasting" and setup an experiment with some undergraduate enology (wine tasting) students.
"The undergraduate subjects came into the lab one week and were given a glass of a red wine and a glass of a white wine. (both Bordeaux, but the experimental details do not include any label or vintage, so we are unable to judge them) They were supplied with a list of potential descriptive words, and told to make a list of words and phrases that best described each wine, either from the supplied list or in their own words. The following week they return to the lab for another session. They were presented with two glasses, one containing white wine, and the other containing the same wine dyed red. They were then given the list of descriptors that they had used to describe the wines from the previous week, and asked to choose which of the wines in front of them best represented each descriptor. It was a forced-choice setup"
So "undergraduate students select the same words to describe a red wine which they had previously used to describe a white" becomes "wine experts can't tell the difference between red and white".