Proceedings of Terroir 1996

The winegrowers of the intercommunal cooperative cellar of Saint Hilaire d'Ozilhan have been practicing terroir selection for ten years. Five years ago, after having equipped themselves with an efficient commercial structure, and anxious to improve knowledge of their terroirs and to better control quantitatively and qualitatively the range of typicality that they can develop, they asked the Syndicate Général des Vignerons Réunis des Côtes du Rhône and the Institut Coopératif du Vin to help them set up an approach to better judge the behavior of the Grenache and Syrah grape varieties in the different terroirs, then to enhance this work through the improving product quality.

The northern vineyards produce wines with a high aromatic richness. The wines of Alsace are appreciated for the diversity of their aromas, the typicality of which was for a long time judged mainly according to the grape variety of origin. Alsatian winegrowers have however widely sensed the importance of the environment of the vine on the quality of the wines. Efforts are made to try to harmonize in a reasoned way the interaction between the natural environment and the plant material with a view to developing the character of the grape variety through the fine expression of the terroir and making the quality and typicality even more inimitable. wines produced in Alsace.

a) wine, a qualitative and user-friendly product, favors a visual support, even for a scientific study because it refers to the image of the terroir, in particular by its visible landscape. b) the vineyard landscape, which is fairly open by definition, favors this type of approach. c) the framework of the Terroir Test conducted by the URVV (INRA – Angers) comprises 15 micro-plots of 100 strains, and requires at this scale precise surveys of the environment, hence systematic shots, of the center of the plot, over 360°, at 50 mm intervals, at 1.70 m from the ground and horizontally.

The AOC Saint-Emilion, one of the most prestigious in Bordeaux, is located on the right bank of the Dordogne upstream from Libourne. The vineyard is planted on Tertiary (Oligocene) and Quaternary geological formations, on which very varied soils have developed. Numerous studies have taken account of this heterogeneity and made it possible to better understand the functioning and viticultural potential of these soils (Duteau et al. 1981, Van Leeuwen, 1991).

The diversity of potential sources of damage to the terroir of an appellation (physical, aesthetic, ecological damage, damage to the image, to collective representation or even, in a broad concept which will not be retained here, to the geographical name identifying the terroir) is accompanied by a fragmentation of the legal sources allowing its protection.

L’utilisation de levures sélectionnées est généralement considérée comme le moyen d’éviter les problèmes fermentaires. Néanmoins de nombreux viticulteurs pensent que ces levures sont à l’origine d’une standardisation des vins et militent pour le respect d’une flore indigène (Bourguignon, 1992).

Le vigneron européen est de plus en plus à la recherche de la valorisation de son terroir par la personnalisation de la typicité de ses produits. Dans ce contexte, il est apparu depuis longtemps que la part des facteurs technologiques ou humains est d’une importance capitale face aux conditions de l’envirormement naturel. Le terroir se construit plus qu’il ne se subit.

In recent years, there has been a growing interest in characterizing the ecological environment of vineyard production, and the growing need to delimit and characterize with precision the different homogeneous viticultural units. This has allowed the development of new studies which have as their objective the Vineyard Zoning. The delimitation and characterization of wine-growing areas poses specific problems in Spain, not only linked to the specific characteristics of the territory, but also to the size, distribution and index of viticultural occupation in the designations of origin.

The terroir offers great variability in the typicity of the wines produced. Following tastings integrating several vintages, the multiple factor analysis of the sensory data revealed a group of taste criteria contributing to the notion of "Power", referenced "Power and Harmony", which makes it possible to differentiate wines from various terroirs of the Middle Loire Valley (Pages et al ., 1987).

In the course of the present work, which is the first part of a study on the “characterization of Barbera dell’Oltrepo Pavese D.O.C.” 30 wines Barbera from 1993 vintage have been compared only regarding their sensory characteristics. An unstructured scale card, composed by 15 descriptors have been used.

In the Champagne vineyards, spring frosts are the cause of significant variations in the volume of the harvest which are very penalizing for the trade. This variability is reflected both in time (years without frost alternating with years with severe frosts) and in space. Certain sectors of the vineyard are in fact statistically more susceptible to frost than others, but each year no municipality can consider itself immune to this climatic accident. The objective of the study is precisely to analyze the spatial distribution of frost and to determine its main mechanisms, linked to the topography of the hillsides, their orientation but also to regional meteorological variables.

The analysis of the distribution of natural plant populations allows an ecological characterization of cultivated environments in thermal, water and trophic terms; it guides the choice or selection of plants (or grape varieties) to cultivate (Astruc et al ., 1984, 1987; Delpoux, 1971; Jacquinet and Astruc, 1979). This approach has given good results in areas where the topography is the determining factor in the ecological differentiation of the terroirs.

The climatic component is one of the elements of the zoning of viticultural potential, alongside the geological and pedological components (Morlat, 1989; Lebon et al , 1993). Many climatic indices have thus been defined to estimate the potential for wine production at the scale of a region or a country (Carbonneau et al ., 1992). The main climatic variables used are temperature and radiation. We note in particular the indices of Branas, Huglin and Ribereau-Gayon (Huglin, 1986). However, few studies have been undertaken on the spatial variability of microclimatic conditions at the scale of a vineyard, a valley, or even a municipality.

The Appellation d'Origine Contrôlée area of ​​Cahors (Lot) covers an area of ​​21,700 ha, spread over 45 municipalities, of which only 4,300 are planted with vines. The main grape variety of this AOC is the Cot noir which represents 70% of the grape varieties, thus giving their typicality to the wines of this region; but despite this importance, to our knowledge, its physiology has remained relatively unstudied.

Approaching the notion of terroir wines at the level of consumption poses a problem due to the absence of a regulatory definition of the term terroir, which is not taken up either at Community level or at national level (the Consumer Code in particular does not define not the land). However, whatever definition is adopted for the terroir, we can retain at the consumer level an identification of the terroir through the different geographical mentions appearing on the labels or on the shelves of the wine shelf.