Vegetative Aroma: Sensory Definition, Chemical Interpretation (and ultimately) Causal Explanation

During the past year we completed sensory studies (descriptive analysis) and chemical analyses on wines made from grapes obtained from four different Cabernet Sauvignon vineyard blocks that were previously identified as producing wines with high levels of vegetal sensory characters.

Within each of the four vineyard sites, cluster microclimates were varied to yield different canopy densities and cluster exposures (with the main effect being differences in light intensity). Vegetal sensory properties (i.e., cooked veggie, bell pepper, and olive aromas) were primarily influenced by vineyard location, however canopy manipulations and row orientation were also important. Measurable levels of 2-methoxy-3-isobutylpyrazine (MIBP) were only found in the wines from one site (Gonzalez; Viticultural Region I) which had the lowest average temperatures of the sites studied.

These wines also were characterized as most vegetal in the sensory descriptive analysis studies. Finally, wines from a separate cluster thinning trial were made and we propose to do sensory analysis of these wines during 2006/07.