New methods and technologies to describe the environment in terroir studies

As an essential element for grapevine development and yield, nitrogen is also involved in the winemaking process and largely affects wine composition. Grape must amino nitrogen deficiency affects the alcoholic fermentation kinetics and alters the development of wine aroma precursors. It is therefore essential to control and optimize nitrogen use efficiency by the plant to guarantee suitable grape nitrogen composition at harvest. Understanding the impact of environmental conditions and cultural practices on the plant nitrogen metabolism would allow us to better orientate our technical choices with the objective of quality and sustainability (less inputs, higher efficiency). This trial focuses on the impact of crop limitation – that is a common practice in European viticulture – on nitrogen distribution in the plant and particularly on grape nitrogen composition. A wide gradient of crop load was set up in a homogeneous plot of Chasselas (Vitis vinifera) in the experimental vineyard of Agroscope, Switzerland. Dry weight and nitrogen dynamics were monitored in the roots, trunk, canopy and grapes, during two consecutive years, using a 15N-labeling method. Grape amino nitrogen content was assessed in both years, at veraison and at harvest. The close relationship between fruits and roots in the maintenance of plant nitrogen balance was highlighted. Interestingly, grape nitrogen concentration remained unchanged regardless of crop load to the detriment of the growth and nitrogen content of the roots. Meanwhile, the size and the nitrogen concentration of the canopy were not affected. Leaf gas exchange rates were reduced in response to lower yield conditions, reducing carbon and nitrogen assimilation and increasing intrinsic water use efficiency. The must amino nitrogen profiles could be discriminated as a function of crop load. These findings demonstrate the impact of plant balance on grape nitrogen composition and contribute to the improvement of predictive models and sustainable cultural practices in perennial crops.

The classification of enological tannins has gained importance following the OIV’s requirement to include their botanical origin on product labels (OIV-OENO 624-2022).

Commercial red wines use the malolactic fermentation process to ensure stability from a microbiological point of view. In this second fermentation, malic acid is converted into L-lactic acid under controlled steps.

The evolution of wine quality issues is historically expressed by the passage from wine quality (what is a wine?) to wine quality (what is a good wine?). Perhaps the next question could be: what is a good sustainable wine? To contribute to reflection on this theme, it may be worthwhile to undertake an exercise in prospective fiction, which we have identified in the hypothesis of the AOD, the “appellation d’origine durable”, a scenario we will develop in the light of developments in the wine industry and the regulation on geographical indications.

La caratterizzazione della frazione volatile aromatica dei vini attraverso l’analisi quali­quantitativa dei diversi composti, ha portato corne primo risultato la netta differenziazione delle annate in prova.