Proceedings of International Terroir Congress 1996

The Pomerol vineyard, located 35 km east of Bordeaux, covers around 800 ha on the left bank of the Isle. There is a system of fluvial terraces with more or less coarse gravel and pebble spreading, resting on a Tertiary substratum ranging from the Middle to Upper Eocene to the Lower Oligocene (Dubreuilh, 1993). This interweaving of terraces of varying thickness results in a brutal superposition of differentiated materials which give rise to various types of soil. Several site studies in this sector of the Libounais show significant morphological and analytical differences from one point to another (Guilloux et al ., 1978; Duteau, 1982; Van Leeuwen et al.., 1989). The distribution of the soils of the Pomerol vineyard was studied and resulted in a cartography at 1/25000th (Merouge, 1995).

Le sujet proposé dans le thème “l’environnement juridique” est plus économique que juridique, et constitue une sorte de complément au sujet qui l’a précédé : analyse des marchés, stratégies commerciales et terroirs”.

Face à l’enjeu d’affirmer et de mieux comprendre la spécificité des vins en relation avec leur origine, la notion de « terroir », avec la richesse de sens et la diversité des perspectives qui l’éclairent, se révèle la clef de voûte de la production et de la valorisation de vins personnalisés et typiques. Asseoir la connaissance des principaux terroirs de la Vallée du Rhône sur des bases autres que celles, jusqu’alors essentiellement empiriques, invoquées dans la seconde grande région française productrice de vins d’AOC, constitue un projet conforme à l’intérêt voué à cet enjeu d’actualité.

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.

Research into the effects of the Terroir is of major interest for the wine sector. The study of Terroir-Vine-Grape relations, even if it is complex, is fundamental for all viticulture: indeed, the quality of the grape must be the result of the most reasoned agro-viticultural management of the vine possible, which must first, to respect a production balance. The goal sought by the winegrower is to obtain a wine, the optimized result of the interactions Terroir-Grape variety. This link to the terroir is therefore essential to establish by taking into account on the one hand the behavior of the vine (which is the cause), and on the other hand, its effects on the grapes and finally on the wine.

The French viticultural appellation areas are the result of an empirical, historical and evolutionary selection which, generally, has consecrated a match between natural factors, grape varieties and viti-vinicultural practices. The notion of terroir is the main basis of the Appellation d'Origine Contrôlée in viticulture. It is based on the one hand on privileged natural factors and on the other hand on the know-how of the winegrowers; the whole allowing the production of a wine endowed with an authenticity and a sensory typicity. Wine-growing practices evolve according to progress in viticulture and oenology, while the natural factors of the terroir are much more stable, with the exception of the vintage. They therefore represent a fundamental pillar of the identity of an appellation vineyard.

Le cru de Bonnezeaux est une des appellations prestigieuses des vins liquoreux et moelleux des Coteaux du Layon et sa réputation est ancienne. L’INAO a effectué sa délimitation en 1953. Le vignoble est situé au nord de la ville de Thouarcé et au sud du village de Bonnezeaux, le long du versant rive droite du Layon, exposé au sud-ouest. La superficie du vignoble est de 156 ha.

A worrying drop in the acidity of wines has been observed in many wine regions, such as Bordeaux (Merlot), Burgundy (Pinot Noir), Côtes-du-Rhône (Grenache) or Rioja (Tempranillo). This lack of acidity is particularly marked in the Midi-Pyrenean vineyards of the Côtes du Frontonnais (Tournier, 1993). However, the acidity of a wine is one of the main factors of its quality, in fact, a low acidity combined with an insufficient tannic structure leads to rapid oxidation of wines and makes them age prematurely.

The research carried out by the URVV of the INRA center in Angers aims to develop a methodology for the integrated characterization of the natural factors of viticultural terroirs, representative of the operating conditions of the vine and the sensory differences of the wines. In this context, the concept of Basic Terroir Unit (UTB) has been developed. The UTB represents a viticultural surface of variable geographical extension, defined as the association in a given place of a geological, pedological and landscape component, Morlat (1989), Riou et al. (1995).

Massif and the first sedimentary formations of the western aureole of the Paris Basin. If it is found all over the world (California, Israel, South Africa), it is in this region that it best asserts its identity. It is one of the most interesting grape varieties due to the variety and complexity of the wines it can produce. It can give very dry or very sweet, still or sparkling wines, fresh when young and sublime when ageing, expressing the characteristics of each vintage as much as those of the terroir. The Chenin is a faithful witness of its geographical, geological, pedological and climatic environment; he is the foil of the land. It has strong aptitudes for the production of sweet wines conditioned by overripe grapes often botrytised in the AOC Coteaux du Layon.Massif and the first sedimentary formations of the western aureole of the Paris Basin. If it is found all over the world (California, Israel, South Africa), it is in this region that it best asserts its identity. It is one of the most interesting grape varieties due to the variety and complexity of the wines it can produce. It can give very dry or very sweet, still or sparkling wines, fresh when young and sublime when ageing, expressing the characteristics of each vintage as much as those of the terroir. The Chenin is a faithful witness of its geographical, geological, pedological and climatic environment; he is the foil of the land. It has strong aptitudes for the production of sweet wines conditioned by overripe grapes often botrytised in the AOC Coteaux du Layon.

During the 1985 harvest, I was able to notice in the taste perception a break in the harmony of the wine during even partial blends of grapes from different plots. At the same time, I noted a good reaction from customers for greater product customization. As a result, I was led to seek the objective limits of the terroir of a cuvée and by a constant and permanent refinement of the parameters specific to each of the terroirs.

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 viticulture of the Douro Delimited Region, one of the heirs of ancestral viticulture, traditionally empirical and of quality, while integrating modernity and contemporary tools, respects and has always present the principles on which it was developed.

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).

A study of the influence of environmental factors on the ripening of grapes under the conditions of Alsace is carried out. Emphasis is placed on the analysis of the mesoclimate and pedoclimate. The experiment is conducted on a network of plots of gewurztraminer grafted on SO4. The production conditions are standardized throughout the device.