Terroir 2004 banner
IVES 9 IVES Conference Series 9 Relationship between terroir and acidity for the red wine grape cultivar Malbec N or Cot N (Vitis vinifera L.) in AOC “Cahors” and “Côtes du Frontonnais “

Relationship between terroir and acidity for the red wine grape cultivar Malbec N or Cot N (Vitis vinifera L.) in AOC “Cahors” and “Côtes du Frontonnais “

Abstract

[English version below]

L’étude préliminaire, réalisée sur les principaux cépages de la région Midi-Pyrénées, a montré que le Cot N possédait des teneurs en acide tartrique dans les moûts et les vins plus élevées que celles des cépages Négrette N, Tannat N, Duras N et Fer Servadou N.
Ce travail a porté sur l’étude du comportement du cépage Cot N sur les terroirs les plus qualitatifs des deux appellations Cahors et Côtes du Frontonnais, ainsi que sur la mise en évidence de l’effet éventuel du terroir sur l’acidité des moûts et des vins.
Les résultats montrent le rôle important joué par la nature physico-chimique des sols sur l’absorption et la translocation des éléments minéraux, et en particulier du potassium par la vigne. Quelque soit le terroir, le Cot N synthétise des quantités similaires d’acides malique et tartrique, mais, celles-ci diffèrent significativement au seuil α = 5 %. Alors que l’acidité titrable et le pH des moûts varient très peu selon le terroir, les pH des vins varient beaucoup en fonction de la nature des sols. Sur les terroirs acides, ces différences sont faibles, alors qu’elles sont très importantes sur le terroir calcaire. Ceci confirme le rôle capital joué par le potassium, qui, au cours de la vinification, entraîne des précipitations importantes d’acide tartrique sous forme de bitartrate de potassium, et corrélativement, l’augmentation du pH des vins. La qualité des vins est donc très dépendante de la prise en compte de la nutrition minérale du cépage et de la pratique d’une fertilisation raisonnée.

A preliminary study on the main red wine grape cultivars of the Midi-Pyrénées area showed that The Cot N presents higher tartaric acid contents in musts and wines than the Négrette, Tannat, Duras and Fer Servadou grape cultivars.
The Cot N grape cultivar is widely planted in the most qualitive terroirs of the “Cahors” and “Côtes du Frontonnais” appellations. Our study focuses on the behaviour of Cot N and therefore, on the possible terroir
effect on Cot N must and wine acidity.
The results show the important role played by the physical and chemical nature of soils in plant nutrient uptake and translocation (particularly potassium). Whatever the terroir, Cot N synthesizes similar quantities of malic and tartaric acids; yet differences are significant α = 5 %. Even if titrable acidity and must pH do not vary much from one terroir to another, pH variation in wines is high depending on the nature of soils. On acidic soils, differences are insignificant whereas they are very important on calcareous soils. These observations confirm the main role of potassium during vinification. Indeed, it accounts for considerable precipitations of tartaric acid in bitartrate of potassium form and for a correlative increase in wine pH levels. The quality of wines depends on a good understanding of mineral nutrition and a reasoned fertilization practice.

DOI:

Publication date: January 12, 2022

Issue: Terroir 2004

Type: Article

Authors

F. Attia (1), E. Besnard (2), F. Laffargue (2), D. Fort (1) and M. Garcia (1)

(1) Centre de Viticulture-Œnologie de Midi-Pyrénées; Avenue de l’Agrobiopôle Auzeville Tolosane, B.P. 107 F – 31320 Castanet Tolosan Cedex, France
(2) Association d’Expérimentation de la Ferme Départementale d’Anglars-Juillac – 46140 Anglars-Juillac, France

Contact the author

Keywords

Terroir, cot n, must and wine acidity, potassium, tartaric and malic acids

Tags

IVES Conference Series | Terroir 2004

Citation

Related articles…

Anthocyanin profile is differentially affected by high temperature, elevated CO2 and water deficit in Tempranillo (Vitis vinifera L.) clones

Anthocyanin potential of grape berries is an important quality factor in wine production. Anthocyanin concentration and profile differ among varieties but it also depends on the environmental conditions, which are expected to be greatly modified by climate change in the future. These modifications may significantly modify the biochemical composition of berries at harvest, and thus wine typicity. Among the diverse approaches proposed to reduce the potential negative effects that climate change may have on grape quality, genetic diversity among clones can represent a source of potential candidates to select better adapted plant material for future climatic conditions. The effects of individual and combined factors associated to climate change (increase of temperature, rise of air CO2 concentration and water deficit) on the anthocyanin profile of different clones of Tempranillo that differ in the length of their reproductive cycle were studied. The aim was to highlight those clones more adapted to maintain specific Tempranillo typicity in the future. Fruit-bearing cuttings were grown in controlled conditions under two temperatures (ambient temperature versus ambient temperature + 4ºC), two CO2 levels (400 ppm versus 700 ppm) and two water regimes (well-watered versus water deficit), both in combination or independently, in order to simulate future climate change scenarios. Elevated temperature increased anthocyanin acylation, whereas elevated CO2 and water deficit favoured the accumulation of malvidin derivatives, as well as the acylation and tri-hydroxylation level of anthocyanins. Although the changes in anthocyanin profile observed followed a common pattern among clones, such impact of environmental conditions was especially noticeable in one of the most widely distributed Tempranillo clones, the accession RJ43.

Assessing the relationship between cordon strangulation, dieback, and fungal trunk disease symptom expression

Grapevine trunk diseases including Eutypa dieback are a major factor in the decline of vineyards and may lead to loss of productivity, reduced income, and premature reworking or replanting. Several studies have yielded results indicating that vines may be more likely to express symptoms of vascular disease if their health is already compromised by stress. In Australia and many other wine-growing regions it is a common practice for canes to be wrapped tightly around the cordon wire during the establishment of permanent cordon arms. It is likely that this practice may have a negative effect on health and longevity, as older cordons that have been trained in this manner often display signs of decay and dieback, with the wire often visibly embedded within the wood of the cordon. It is possible that adopting a training method which avoids constriction of the vasculature of the cordon may help to limit the onset of vascular disease symptom expression. A survey was conducted during the spring of two consecutive growing seasons on vineyards in South Australia displaying symptoms of Eutypa lata infection when symptomless shoots were 50–100 cm long. Vines were assessed as follows: (i) the proportion of cordon exhibiting dieback was rated using a 0–100% scale; (ii) the proportion of canopy exhibiting foliar symptoms of Eutypa dieback was rated using a 0–100% scale; (iii) the severity of strangulation was rated using a 0–4 point scale. Images were also taken of each vine for the purpose of measuring plant area index (PAI) using the VitiCanopy App. The goal of the survey was to determine if and to what extent any correlation exists between severity of strangulation and cordon dieback, in addition to Eutypa dieback foliar symptom expression.

Current climate change in the Oplenac wine-growing district (Serbia)

Serbian autochthonous vine varieties Smederevka (for white wines) and Prokupac (for rosé and red wines) are the primary representatives of typical characteristics of wines and terroir of numerous wine-growing areas in Serbia. In the past, these varieties were the leading vine varieties, however, as the result of globalization of winemaking and the trend of consumption of wines from widely prevalent vine varieties, they were replaced by introduced international varieties. Smederevka and Prokupac vine varieties are characterized by later time of grape ripening, and relative sensitivity to low temperatures. Climate conditions can be a restrictive factor for production of high-quality grapes and wine and for the spatial spreading of these varieties in hilly continental wine-growing areas.
This paper focuses on the spatial analysis of changes of main climate parameters, in particular, analysis of viticultural bioclimatic indices that were determined for the purposes of viticulture zoning of wine-growing areas in the period 1961-2010, and those same parameters determined for the current, that is, referential climate period (1988-2017). Results of the research, that is, analysis of climate changes indicate that the majority of examined climate parameters in the Oplenac wine-growing district improved from the perspective of Smederevka and Prokupac vine varieties. These studies of climate conditions indicate that changes of analyzed climate parameters, that is, bioclimatic indices will be favorable for cultivation of varieties with later grape ripening times and those more sensitive to low temperatures, such as the autochthonous vine varieties Smederevka and Prokupac, therefore, it is recommended to producers to more actively plant vineyards with these varieties in the territory of the Oplenac wine-growing district.

Sustaining wine identity through intra-varietal diversification

With contemporary climate change, cultivated Vitis vinifera L. is at risk as climate is a critical component in defining ecologically fitted plant materiel. While winegrowers can draw on the rich diversity among grapevine varieties to limit expected impacts (Morales-Castilla et al., 2020), replacing a signature variety that has created a sense of local distinctiveness may lead to several challenges. In order to sustain wine identity in uncertain climate outcomes, the study of intra-varietal diversity is important to reflect the adaptive and evolutionary potential of current cultivated varieties. The aim of this ongoing study is to understand to what extent can intra-varietal diversity be a climate change adaptation solution. With a focus on early (Sauvignon blanc, Riesling, Grolleau, Pinot noir) to moderate late (Chenin, Petit Verdot, Cabernet franc) ripening varieties, data was collected for flowering and veraison for the various studied accessions (from conservatory plots) and clones. For these phenological growing stages, heat requirements were established using nearby weather stations (adapted from the GFV model, Parker et al., 2013) and model performances were verified. Climate change projections were then integrated to predict the future behaviour of the intra-varietal diversity. Study findings highlight the strong phenotypic diversity of studied varieties and the importance of diversification to enhance climate change resilience. While model performances may require improvements, this study is the first step towards quantifying heat requirements of different clones and how they can provide adaptation solutions for winegrowers to sustain local wine identity in a global changing climate. As genetic diversity is an ongoing process through point mutations and epigenetic adaptations, perspective work is to explore clonal data from a wide variety of geographic locations.

Local adaptation tools to ensure the viticultural sustainability in a changing climate

[lwp_divi_breadcrumbs home_text="IVES" use_before_icon="on" before_icon="||divi||400" module_id="publication-ariane" _builder_version="4.19.4" _module_preset="default" module_text_align="center" module_font_size="16px" text_orientation="center"...