Wine Tasting Tuscany White Wines - San Gimignano, Siena

A Study on Aromagramme of Vernaccia di San Gimignano wine - La Lastra (2000-2023)

Preliminary remarks
The main varietal limit of Vernaccia di San Gimignano wine (VSG) is the aroma intensity of its different volatile components of high olfactory impact.
The need of understanding the influence of all the different variables, both from a bio-agronomic and technological point of view on VSG bouquet, has led us in the sensorial/molecular world of Vernaccia. The project started in 2000, when I obtained my degree cum laude in Agricoltural Sciences and Technologies at the University of Florence (Scienze e Tecnologie Agrarie - UNIFI). The title of my Graduation Thesis was “Miglioramento genetico della Vernaccia di San Gimignano” 2000-2002 (Genetic Improvement of Vernaccia di San Gimignano 2000-2002), in cooperation with ISMAA (Tn - Fondazione Edmund Mach) oenologist E. Paternoster and the ISMAA researchers G. Versini and D. Porro. The project is still in progress today.

Introduction
The sensorial analysis from 2000 to 2021 (E. Paternoster, R. Spanu, C. Betti), together with the chemical profile (G. Versini 2002), and the nature of the compounds identified in the volatile fraction (G. Versini 2002), give us the possibility of tracing the basic aromagramme of “Vernaccia di San Gimignano - La Lastra” wine, removing the influence of the year of the vintage.

In order to simplify the interpretation of data, thanks to the ANOVA Variance Analysis and to the factorial Analysis - Varimax rotation method - we have selected 3 complex factors (D.Porro 2000 - 2002), i.e. three sets of simple descriptors, able to describe VSG.

Outcome and Discussion
The main olfactory element of Vernaccia di San Gimignano is the complex factor "fruity-ripe" (descriptors: tropical, citrus, spicy, hazelnut, honey). This factor constantly emerges remarkably and it is confirmed by definitely high standards of fatty acids ethyl esters, starting from butyric acid (hints of papaya, ripe apple) down to caprice (hints of apple and sweetish hints). These additional elements in the overall olfactory line give strength to the single evaluation.

The "fermentative-citrine" complex factor, the expression of several simple factors (fruity fermentative, floral, rose and acid), does not register significant values in the composition of the final bouquet. This data are confirmed at a chemical level by an negligible concentration of Phenethyl alcohol (hints of rose-carnation with an olfactory threshold of 40mg/l, as well as free terpenical compounds.

The complex "vegetal" factor (anise-fennel, herbaceous, hay-tobacco), even if variations can be registered in different years, has small impact on the wine olfactory composition.

Conclusions
The basic bouquet of “Vernaccia di San Gimignano - La Lastra” wine features a rich olfactory non aromatic complexity that can be described thanks to the semantic hyperspace "fruity-ripe" exalting (through fixation) part of the volatile fermentative (but not pre-fermentative) compounds. To be noticed the importance of the microbiological factor in the olfactory composition of this wine, the expression of a warm Tuscany in white.

Christian Betti