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…

Impact on leaf morphology of Vitis vinifera L. cvs Riesling and Cabernet Sauvignon under Free Air Carbon dioxide Enrichment (FACE)

Atmospheric carbon dioxide (CO2) concentration has continuously increased since pre-industrial times from 280 ppm in 1750, and is predicted to exceed 700 ppm by the end of 21st century. For most of C3 plant species elevated CO2 (eCO2) improve photosynthetic apparatus results in an increased plant biomass production. To investigate the effects of eCO2 on morphological leaf characteristics the two Vitis vinifera L. cultivars, Riesling and Cabernet Sauvignon, grown in the Geisenheim VineyardFACE (Free Air Carbon dioxide Enrichment) system were used. The FACE site is located at Geisenheim University (49° 59′ N, 7° 57′ E, 94 m above sea level), Germany and was implemented in 2014 comparing future atmospheric CO2-concentrations (eCO2, predicted for the mid-21st century) with current ambient CO2-conditions (aCO2). Experiments were conducted under rain-fed conditions for two consecutive years (2015 and 2016). Six leaves per repetition of the CO2 treatment were sampled in the field and immediately fixed in a FAA solution (ethanol, H2O, formaldehyde and glacial acetic acid). After 24 h leaf samples were transferred and stored in an ethanol solution. Subsequently, leaf tissue was dehydrated using ethanol series and embedded in paraffin. By using a rotary microtomesections of 5 µm were prepared and fixed on microscopic slides. Subsequent the samples were stained using consecutive staining and washing solutions. Afterwards pictures of the leaf cross-sections were taken using a light microscope and consecutive measurements were conducted with an open source image software. Differences found in leaf cross-sections of the two CO2 treatments were detected for the palisade parenchyma. Leaf thickness, upper and lower epidermis and spongy parenchyma remained less affected under eCO2 conditions. The observed results within grapevine leaf tissues can provide first insights to seasonal adaptation strategies of grapevines under future elevated CO2 concentrations.

Aromatic maturity is a cornerstone of terroir expression in red wine

Harvesting grapes at adequate maturity is key to the production of high-quality red wines. Enologists and wine makers define several types of maturity, including technical maturity, phenolic maturity and aromatic maturity. Technical maturity and phenolic maturity are relatively well documented in the scientific literature, while articles on aromatic maturity are scarcer. This is surprising, because aromatic maturity is, without a doubt, the most important of the three in determining wine quality and typicity (including terroir expression). Optimal terroir expression can be obtained when the different types of maturity are reached at the same time, or within a short time frame. This is more likely to occur when the ripening takes place under mild temperatures, neither too cool, nor too hot. Aromatic expression in wine can be driven, from low to high maturity, by green, herbal, fresh fruit, ripe fruit, jammy fruit, candied fruit or cooked fruit aromas. Green and cooked fruit aromas are not desirable in red wines, while the levels of other aromatic compounds contribute to the typicity of the wine in relation to its origin. Wines produced in cool climates, or on cool soils in temperate climates, are likely to express herbal or fresh fruit aromas; while wines produced under warm climates, or on warm soils in temperate climates, may express ripe fruit, jammy fruit or candied fruit aromas. Growers can optimize terroir expression through their choice of grapevine variety. Early ripening varieties perform better in cool climates and late ripening varieties in warm climates. Additionally, maturity can be advanced or delayed by different canopy management practices or training systems.

Impact of climate change on the viticultural climate of the Protected Designation of Origin “Jumilla” (SE Spain)

Protected Designation of Origin “Jumilla” (PDO Jumilla) is located in the Spanish provinces of Albacete and Murcia, in the South-eastern part of the Iberian Peninsula, where most of the models predict a severe impact of climate change in next decades. PDO Jumilla covers an area of 247,054 hectares, of which more than 22,000 hectares

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.

Copper contamination in vineyard soils of Bordeaux: spatial risk assessment for the replanting of vines and crops

Copper (Cu) is widely and historically used in viticulture as a fungicide against mildew. Cu has a strong affinity for soil organic matter and accumulates in topsoil horizons. Thus, Cu may negatively affect soil organisms and plants, consequently reducing soil fertility and productivity. The Bordeaux vineyards have the largest vineyard surfaces (26%) within French controlled appellation and a great proportion of French wine production (around 5 million hl per year). Considering the local context of vineyard surfaces decreasing (vine uprooting) and possible new crop plantation, the issue of Cu potential toxicity rises. Therefore, the aims of this work are firstly to evaluate the Cu contamination in vineyard soils of Bordeaux, secondly to produce a risk assessment map for new vine or crop plantation. We used soil analyses from several local studies to build a database with 4496 soil horizon samples. The database was enhanced by means of pedotransfer functions in order to estimate the bioaccessible (EDTA-extractable) Cu in soils of samples without measurements. From this database, 1797 georeferenced samples with CuEDTA concentrations in the topsoil (0-50 cm depth) were used for kriging interpolation in order to produce the spatial distribution map of CuEDTA in vineyard soils. Then, the spatial distribution of Cu was crossed with vine uprooting surfaces and municipality boundaries. CuEDTAconcentrations ranged from 0.52 to 459 mg/kg and showed clear anomalies. Our results from spatial analysis showed that almost 50% of vineyard soil surfaces have CuEDTA concentrations higher than 30 mg/kg (moderate risk for new plantation) and 20% with concentrations higher than 50 mg/kg (high risk for new plantation). A decision-support map based on municipalities was realised to provide a simple tool to stakeholders concerned by land use management.