Monday, April 4, 2016

From a Haha moment to an Aha moment…Part 2:

My previous post was the first in a series discussing the white-wine-dyed-red study by Morrot, Brochet, and Dubourdieu.* In this study, students of oenology created individual vocabularies to describe a white wine (sémillon and sauvignon blend) and a red (cabernet-sauvignon and merlot), and then were invited to smell/taste and describe the same white wine, and the white wine dyed with anthocyanidins to look like a red wine. 

In today’s post we will focus on how these vocabularies were developed, and what they were thought to mean. 

The authors started with lists of descriptors culled from French commentators on wine, and submitted these lists to computer analysis. This analysis consistently yielded two sets of words, one set for white wines and one set for red wines. From this exercise the authors concluded that there is a specific type of vocabulary used to describe each type of wine. The authors further conclude that even for the experts, the color of the wine triggers the description, with the result that the description reflects color associations rather than intrinsic flavors of the wine. 

The authors provide a table of the words culled from 3000 tasting comments written by Jacques Dupont between 1991 and 1996** in La lettre de Gault & Millau. What is fascinating to note is that for white wine there were 16 flavor words that Dupont associated exclusively with white wine, but only two he associated exclusively with red wine. In fact the word Dupont used most frequently by far is “cherry,” but he associated “cherry” with white wine 15.5% of the time! 

That said, red fruits are present on the red wine list, and white or yellow fruit on the white wine list, suggesting, at least at first glance, that color may direct the choice of descriptors. The authors understand this to mean that when the students used a red fruit descriptor to describe the white-wine-dyed-red, they were being guided by their eyes and not their smell.

We must remember that wine is a complex fluid with hundreds of volatiles, the most prominent being alcohol. We can distinguish and identify at most only 4 different odors in any mixture.**  As noted in the study by Gottfried and Dolan,*** we become aware of odors that are congruent with what we see, but are likely to be unaware of odors that are incongruent. The students weren’t really being fooled—they just had their attention directed to a specific array of odors among the many.

In the next post we will explore what the students actually experienced and why. 

* Morrot G., Brochet F., Dubourdieu D. The Color of Odors. Brain and Language, doi:10.1006/brln.2001.2493.

** Livermore A., Laing D.G. The influence of odor type on the discrimination and identification of odorants in multicomponent odor mixtures. Physiology & Behavior Volume 65, Issue 2, 15 November 1998, pages 311–320.


*** Gottfried, Jay A., Dolan, Raymond J. The Nose Smells What the Eye Sees: Crossmodal Visual Facilitation of Human Olfactory Perception. Neuron, 39:375-386, 2003.

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