Terroir 1996 banner
IVES 9 IVES Conference Series 9 How to resolve the lack acidity in wines by better understanding of the adequation of grape varietal-terroir: Negrette grape in the terroir of Côtes du Frontonnais

How to resolve the lack acidity in wines by better understanding of the adequation of grape varietal-terroir: Negrette grape in the terroir of Côtes du Frontonnais

Abstract

Le manque d’acidité des vins est un sujet préoccupant dans de nombreux vignobles car l’acidité est un facteur déterminant de la qualité des vins, en liaison avec la nutrition minérale de la vigne.
Dans le but de résoudre ce problème de manière agronomique, une double expérimentation a été mise en place sur la Négrette, cépage principal des Côtes du Frontonnais, qui donne des vins peu acides. Tout d’abord en culture hors-sol nous avons montré que la teneur en potassium de la solution nutritive est corrélée positivement à celle des feuilles, des moûts, ainsi qu’au pH des vins. Par contre, un apport complémentaire de calcium à la solution nutritive diminue la teneur en potassium des limbes, des moûts, et le pH des vins. En plein champ, sur sols acides, pauvres en calcium, nous avons constaté que plus le sol contient du potassium, plus la Négrette l’absorbe, plus on en retrouve dans les moûts et les vins et moins ces derniers sont acides.
En liaison avec ces résultats nous avons déterminé les terroirs de l’ A.O.C. Côtes du Frontonnais (vignoble du Sud Ouest de la France ) et étudié l’effet d’un amendement calcaire sur l’acidité des vins issus de chacun de ces terroirs. Cette appellation se situe sur de vieilles terrasses alluviales, décalcifiées et de topographie plane. Le climat étant homogène sur toute l’appellation, quatre terroirs ont été identifiés, ils correspondent aux types de sols rencontrés dans cette zone : les graves (très riches en cailloux), les boulbènes caillouteuses (riches en cailloux et limons), les boulbènes sableuses (riches en sable) et les boulbènes blanches (riches en limons). Les résultats montrent que le chaulage entraîne une diminution des teneurs en potassium dans les feuilles, les moûts et les vins (liée à l’antagonisme K-Ca) et une augmentation de l’acidité des vins (liée à la diminution de la précipitation de l’acide tartrique par le potassium). De plus, le chaulage a un effet variable en fonction des terroirs, et les boulbènes caillouteuses donnent les vins les plus acides.
Cette étude montre que sur sols acides, le chaulage est une bonne alternative pour améliorer l’acidité des vins de Négrette. Elle met en évidence l’importance de la prise en compte de la nutrition minérale du cépage (plus particulièrement la nutrition potassique) et du terroir sur la qualité des vins.

The lack of acidity is a matter of concern in many vineyards. Acidity is a determining factor in wine quality and are influenced by the minerai nutrition of the vine.
In order to resolve this problem a double experiment was carried out on Négrette, the principal cultivar in the Côtes
du Frontonnais Appellation, that produces wines which are not very acidic. In the hydroponic culture, the level of potassium nutrition in the solution was positively correlated to leave and must potassium content, as well as to wine pH. However, a complementary calcium addition decreased the leave, berry and must potassium contents and the wine pH. In the field trail, on an acid soil with a lack of calcium, evidence was found that a higher potassium content of soils leads to a higher absorption of potassium by Négrette. This increase in potassium absorption can lead to higher potassium content of musts and wines, thereby reducing their acidity.
This study also aimed to determinate the different terroirs of the “Appellation d’Origine Contrôlée Côtes du Frontonnais” which is situated in the South-West of France and to study the effect of liming on the acidity of wines from each terroir. This appellation is situated on ancient alluvial terraces, which is decalcified with its topography levelled off. Four terroirs were differentiating corresponding to typical soils of the appellation: “graves” (gravely stone ), stony “boulbènes” (high stone content), sandy “boulbènes” (high sand content) and the white “boulbènes” (high limestone content). The results showed that liming lowers the level of potassium in leaves, musts and wines (linked to the K-Ca antagonism) and leads to an increase in the acidity in wines (related to a decrease in potassium bitartrate precipitation). It was also found that the effect of liming on wine acidity would depend on the terroir, leading to more acid wines from the stony “boublènes”.
This study shows that liming can be used to improve the acidity of Négrette wines on acids soils. It also highlights the importance of mineral nutrition (in particular potassium nutrition) and consequently the importance of terroir on wine quality.

DOI:

Publication date: February 15, 2022

Issue: Terroir 2002

Type: Article

Authors

M. GARCIA, H. IBRAHIM and A. CADET

Centre de viticulture et d’œnologie de Midi-Pyrénées
Avenue de l’ agrobiopôle, 31 320 Auzeville-Tolosane

Contact the author

Keywords

 terroir, acidité des vins, nutrition minérale, Fronton, Négrette
terroir, wine acidity, minerai nutrition, Fronton, Négrette

Tags

IVES Conference Series | Terroir 2002

Citation

Related articles…

Wine without added SO2: Oxygen impact and color evolution during red wine aging

SO2 play a major role in wine stability and evolution during its aging and storage. Winemaking without SO2 is a big challenge for the winemakers since the lack of SO2 affects directly the wine chemical evolution such as the aromas compounds as well as the phenolic compounds. During the red wine aging, phenolic compounds such as anthocyanin, responsible of the red wine colour, and tannins, responsible of the mouthfeel organoleptic properties of wine, evolved quickly from the winemaking process to aging [1]. A lot of new interaction and molecules occurred lead by oxygen[2] thus the lack of SO2 will induce wine properties changes. Nowadays, the phenolic composition of the wine without added SO2 have not been clearly reported.

FLAVANOL COMPOSITION OF VARIETAL AND BLEND WINES MADE BEFORE AND AFTER FERMENTATION FROM SYRAH, MARSELAN AND TANNAT

Background: The Flavan-3-ol extraction from grape skin and seed during red-winemaking and their retention into wines depend on many factors, some of which are modified in the winemaking of blend wines. Recent research shows that Marselan, have grapes with high proportion of skins with high concentrations of flavanols, but produces red-wines with low proportion of skin derived flavanols, differently to the observed in Syrah or Tannat. But the factors explaining these differences are not yet understood.

Contribution of soil for tipifiyng wines in four geographical indications at Serra Gaúcha, Brazil

Brazil has a recent history on geographical indications and product regulation for high quality wines. The first geographic indication implemented was the Vale dos Vinhedos Indication of Procedence (

Influence du terroir sur la composition en flavonoïdes de la baie de raisin de Cabernet franc en Moyenne Vallée de la Loire

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).

WINE WITHOUT ADDED SO₂: OXYGEN IMPACT AND EVOLUTION ON THE POLYPHENOLIC COMPOSITION DURING RED WINE AGING

SO₂ play a major role in the stability and wine during storage. Nowadays, the reduction of chemical input during red winemaking and especially the removing SO₂ is a growing expectation from the consumers. Winemaking without SO₂ is a big challenge for the winemakers since the lack of SO₂ affects directly the wine chemical evolution such as the phenolic compounds as well as its microbiological stability.