Wine experts usually rely on chemical tracers of qualities or defects to judge wines. While part of their expertise is determined by their sensory ability to detect these key compounds, their level of sensitivity is generally unknown. The olfactory detection thresholds for 10 key odorant compounds in wine were, therefore, measured in a large sample of professionals (100 < n < 150). The experts' sensitivity to two tastants, tartaric acid and alum (respectively, sour and astringent compounds) was also tested. The study confirms that distributions of individual detection thresholds were very large (>3 log10 units). Comparing the abilities of the experts to detect the whole sample of chemicals tested, we showed that their sensitivity profiles were very different. Detection threshold distribution asymmetries suggested specific hyposmias or hyperosmias for bionone, 2-isobutyl-3-methoxypyrazine, 2,4,6-trichloroanisole, diacetyl, and linalool. Interestingly, we found that academic degrees in tasting and enology do have an impact on odor detection thresholds for two compounds, diacetyl and mixed ethylphenols.

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Mental imagery has been used successfully in sensorimotor training, but rarely to improve sensory skills. Novices, undergraduate enology students (intermediates) and wine experts were asked to repeatedly imagine the visual images or smells of odorant sources presented in picture form. Olfactory abilities, odor sensitivity and identification performance were compared before and after mental training to check the differential effects of the two types of sensory training. We demonstrated that, like repeated objective odorant stimulations, repeated imagination of odors was able to enhance olfactory performance in objective perception. Both odor detection and identification abilities were improved. However, according to our results: (1) the effect was odorant specific; and (2) the impact of training on identification was restricted to wine experts. In addition, interestingly, the experts' olfactory identification performance apparently deteriorated following specific visual attention during the training phase. PRACTICAL APPLICATIONSOne extremely important aspect of sensory evaluation is training panelists to achieve consistent results. The results demonstrated the effectiveness of olfactory mental imagery as training strategy. The findings demonstrated that olfactory mental imagery was able to modify olfactory capabilities of wine professionals, with results comparable to those obtained using perceptual training. Consequently, olfactory mental imagery is an excellent tool for training the olfactory capacities of panelists, and may be extended to perfumers, flavorists and tasting panelists with a view to improving product quality control, without material stimulus such as chemical supports.