The “aromatic signature” that certifies a “cru”: Tedeschi’s research, in Valpolicella

“Crus”, whether territorial or estate, are increasingly important in the high-end wine market. And their enhancement, in addition to the glass and “storytelling”, also comes through research. And scientific substance has been given to the sensory differences felt in wines from different crus by the study, commissioned by the Tedeschi family, at the head of one of the most famous realities of Valpolicella and Amarone, its princely wine, to Professor Maurizio Ugliano in collaboration with the Department of Biotechnology of the University of Verona to which he belongs, which has identified on a chemical basis the “aromatic signature” of the terroir.
Expressing “a wine’s sense of place” has been a constant in the Tedeschi winery’s philosophy since 1964 when Renzo Tedeschi - 90 years old just turned - decided to vinify the grapes from the Monte Olmi vineyard separately. “A foresight that has been preserved even in the generational transition”, as pointed out by Sabrina Tedeschi, who, with her siblings Antonietta and Riccardo, wanted to start this study in 2017 to give substance to their father’s pioneering intuition about the existence of a chemical code that expresses the place of origin of the wine.
The first results of the study, presented in 2021, identified the aromatic characteristics of grapes and wines from individual vineyards and identified the main factors involved in their expression. Two years later, a very important step forward has been taken, which moreover has general repercussions for our knowledge of the olfactory substances in wine.
“After coming to identify the aromatic imprint of individual vineyard parcels and verifying that it remains unchanged in terms of quality regardless of vintage trends”, illustrated Riccardo Tedeschi, who is the winemaker among the three siblings, “with this new phase of research we wanted to understand its evolution over time”.
However, if in wines from the same vineyard, even in different vintages, on sensory analysis, it is quite easy to perceive characterizing markers, their analytical identification is on the contrary very difficult. “We have scientifically identified the aromatic identity of wines from the vineyards of La Fabriseria and Monte Olmi, which they had already sensory identified”, Maurizio Ugliano emphasized in the presentation of the results in the Valpolicella winery, “giving name and surname to the volatile compounds that determine them. Knowing them can direct vineyard management and winery practices”. And it has not been easy, so much so that to date there are very few studies in the world on the subject. The difficulties are many and enormous, from analytical techniques to the number of volatiles, their nature and concentration. “To analyze the aroma”, Ugliano explained, “you cannot use wine as is because the aromatic compounds are present in traces, so you have to extract them first. We used 4-5 different methods of analyzing the aromatic fraction, which consists of several hundred substances of which, however, only a small number are odorous. In fact, some of the compounds that contribute to aromatic signatures are not present in young grapes or wines, but are formed with aging. Not only that. 50% of them have no odor, some of them have a distinctly unpleasant one, and only by combining, as in a chorus, do they produce what we sense by smell. Moreover, their concentration varies with the vintage and with the presence or absence of grape drying”. And it is precisely the understanding of the origin of some of the aroma-defining compounds and with it their role in the aging of Amarone wines that represents a particularly qualifying and fascinating aspect of the study.
“In the case of the Amarone samples obtained from the Monte Olmi vineyard, through the collaboration that the Department of Biotechnology of the University of Verona has had for years with the Universities of Bordeaux and Federico II in Naples”, Ugliano continued, “it was possible to highlight the high content of some hitherto little-known terpenes, which can support the aromatic freshness and therefore the longevity of the wine over time. In particular, analysis has shown that some Amarones, including those of the Tedeschi winery, are distinguished by the presence of certain odorous substances with complex olfactory characteristics. Among these, cineols are of particular interest because they support the expression of balsamic aromatic notes that are at times reminiscent of the smell of eucalyptus leaves. For wines to develop these characteristics over time, it is important that certain compounds, aromatically unscented and therefore often overlooked by researchers, are present in the grapes, which then in the weakly acidic environment of the wine slowly form the cineols themselves. It is therefore to all intents and purposes a reservoir of aroma precursors that over time contribute to enriching the wine’s aroma profile with new characters. The interesting aspect is that drying, particularly in the case of the Corvina variety, helps the formation of specific aroma precursors to then support the development of these balsamic scents, through mechanisms that we still do not fully understand”.
Moreover, thanks to the use of a new analytical method developed by the Department of Biotechnology at the University of Verona, the contribution to the aromatic signatures of wines of another hitherto little-studied compound in Italian red wines, dimethyl sulfide, has been highlighted. This is an aromatic compound that at high concentrations imparts to the wine odors reminiscent of truffles and underbrush, while when present at lower levels it supports the expression of odorous notes of black fruits and cassis. In young wines it is almost absent, while with aging it increases significantly and is considered a key aroma in the aging bouquet of Bordeaux and Rhone Valley Syrah-based reds.
“In our study”, Maurizio Ugliano concluded, “we found high levels of dimethyl sulfide in wines made from grapes with a particular profile about nitrogen compounds, a reflection of soil-plant interactions. Therefore, it seems legitimate to consider this compound as one of the key factors in the aromatic expression of a wine's terroir. In the case of the terroirs studied, the Fabriseria vineyard and a specific plot within the Maternigo estate were found to be most associated with the development of dimethyl sulfide during wine aging”. “The study confirms, once again”, stressed Riccardo Tedeschi, “that Amarone is a wine of terroir, on which the production of wines with characteristics of complexity, body and elegance unlike any other depends. It is up to us to choose the most suitable vineyards and to process the grapes so that they release their maximum potential”.