Brett is an “off-aroma” caused by the Brettanomyces yeast. It sometimes gives wine a “barnyard” or leathery character which for me contributes to the earthy impression which I highly prize. But it more often produces chemical notes and “band-aid” aromas which are just disgusting. Handled with care it is not a flaw in my estimation.
But because wine often has earthy aromas independent of infection with this yeast, I’m often not sure whether it is “brett” that I am smelling or just the inherent quality of the wine.
According to this recent study, wine professionals differ significantly in their ability to detect “brett”. Winemakers, winegrowers, wine merchants, and wine brokers, all who regularly participated in formal tastings, were tested for their ability to detect the compounds associated with “brett”.
As reported by the Academic Wino:
- Wine expert profession had a significant influence on the ability of individuals to detect Brett character in wine, as well as off-odors in general.
- There was closer agreement among winemakers in regards to the detection of off-odors compared to all other professions studied.
- Variations in detection abilities among the individual participants were very large – specifically, the difference in ethylphenol concentrations identified was 2.5×103 between the most sensitive and the least sensitive perceivers.
- Participants who were winemakers as well as those with academic tasting degrees were found to be significantly better at identifying Brett character in wines compared with other wine experts without academic degrees or in other professions.
- There were no effects of age on Brett detection ability in the participants in this study.
This is not surprising. After all it is the job of the winemaker to detect flaws in a wine and eliminate them at each stage of the winemaking process. So through their training and their experience they’ve acquired a sensitivity to even low levels of these compounds. The rest of us only occasionally experience “brett” because it is often eliminated from the finished product, or we attribute the aromas to the inherent features of the wine and never make the connection.
Another example of how expert opinion can vary based on differences in training and experience.