Terroir 2004 banner
IVES 9 IVES Conference Series 9 Effects of soil and climate on wine style in Stellenbosch: Sauvignon blanc

Effects of soil and climate on wine style in Stellenbosch: Sauvignon blanc

Abstract

[English version below]

Une étude a été menée pendant neuf ans sur deux vignes non-irriguées de Sauvignon blanc commercialisés, plantées à différentes localités (A et B) dans le district de Stellenbosch. Deux parcelles expérimentales, situées sur deux formations géologiques différentes, ont été identifiées au sein de chaque vignoble. A chaque localité une des formations pédologiques montre des signes d’humidité en profondeur, tandis que l’autre est relativement sèche. Malgré leur proximité géographique (9 km), le méso-climat diffère entre les deux localités, principalement en raison de l’altitude, A étant situé à 413 m et B à 148 m d’altitude. La température maximale de février est 1.9ºC plus basse en A qu’en B, les températures nocturnes sont aussi les plus basses en A. Les raisins de la localité la plus fraîche (A) sont généralement récoltés deux semaines plus tard que ceux de la localité la plus chaude (B). A la localité la plus fraîche, la maturation est aussi affectée par la formation pédologique : les raisins issus du sol le plus sec ont été vendangés approximativement une semaine avant ceux ceux issus du sol plus humide. Cependant la maturation n’a pas été affectée par le sol à la localité la plus chaude. A la localité la plus fraîche, les vins issus du sol plus humide révèlent généralement un caractère végétatif frais prédominant (herbacé, poivre vert, eucalyptus, menthe) et ceux issus du sol plus sec des caractéristiques de légumes cuits (haricots verts, asperges, olive, artichaut) et de fruits. Le style de vin n’a pas été affecté par la formation pédologique à la localité la plus chaude oú les caractères de fruits tropicaux dominent. Les résultats suggèrent que le style du vin de Sauvignon blanc de Stellenbosch n’est pas seulement affecté par le climat, mais aussi par le sol.
A nine-year study was carried out in two non-irrigated, commercial Sauvignon blanc vineyards, grown at different localities (A and B) in the district of Stellenbosch. Two experimental plots, representing different soil forms, were identified within each vineyard. At both localities one of the soil forms showed signs of wetness with depth, while the other one was relatively dry. Despite their geographic proximity (9 km), meso-climate differed between the two localities, largely on account of A being situated at higher altitude (413 m) than B (148 m). Maximum temperature for February was 1.9ºC lower for A than for B, while night temperature was also lowest at A. Grapes at the cooler locality (A) were generally harvested two weeks later than those at the warmer one (B). At the cooler locality ripening was also affected by soil form, with grapevines on the drier soil being harvested approximately one week earlier than those on the wetter soil. Ripening was not affected by soil form at the warmer locality. At the cooler locality, wine from the wetter soil generally exhibited a prominent fresh vegetative character (grass, green pepper, eucalyptus, mint), in comparison to cooked vegetative (green beans, asparagus, olive, artichoke) and fruity characteristics for the one from the drier soil. Wine style was not affected by soil form at the warmer locality, with tropical fruit character being dominant. Results suggested that the style of Sauvignon blanc wines from Stellenbosch is not only affected by climate, but also by soil form.

DOI:

Publication date: January 12, 2022

Issue: Terroir 2004

Type: Article

Authors

W.J. Conradie (1)* and M.P. Olivier (1)**

(1) ARC Infruitec-Nietvoorbij, Private Bag X5026, 7599 Stellenbosch, Republic of South Africa

* Present address: Department of Soil Science, University of Stellenbosch, 7600 Stellenbosch, Republic of South Africa
** Presenting author

Contact the author

Keywords

Soil, climate, wine style, Sauvignon blanc, Stellenbosch, South Africa

Tags

IVES Conference Series | Terroir 2004

Citation

Related articles…

Comportement de différents clones de Sauvignon blanc dans certains terroirs viticoles du Friuli-Venezia Giulia (Nord-Est de l’Italie)

The worldwide reputation of Sauvignon Blanc has led technicians to ask themselves various questions about the cultivation of this variety: choice of the most suitable localities, the most effective agronomic strategies and the most appropriate wine-growing techniques, to bring out its particular aroma.

Étude de la flore levurienne de différents terroirs alsaciens

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).

The impact of Saccharomyces yeasts on wine varietal aroma, wine aging and wine longevity

The objective of the present work is to assess yeast effects on the development of wine varietal aroma throughout aging and on wine longevity.

Three independent experiments were carried out; two fermenting semi-synthetic musts fortified with polyphenols and aroma precursors extracted from Tempranillo (1) or Albariño (2) grapes and with synthetic precursors of polyfunctional mercaptans (PFMs), and a third in which a must, mixture of 6 different grape varieties was used. In all cases, fermentations were carried out by different Saccharomyces cerevisiae strains and one S. kudriavzevii, and the obtained wines were further submitted to anoxic accelerated aging to reproduce bottle aging. The volatile profile of the wines was analyzed using several chromatographic procedures, in order to provide a comprehensive evaluation of wine aroma. Aroma compounds analyzed included fermentation volatile metabolites, grape-derived aroma compounds including PFMs, and Strecker aldehydes (SA).

Results revealed that the effects of yeast on wine aroma throughout its self-life extend along three main axes:

1. A direct or indirect action on primary varietal aroma and on its evolution during wine
aging.

2. The direct production of SA during fermentation and/or their delayed formation by producing the required reagents (amino acids + dicarbonyls) for Strecker degradation
during anoxic aging.

3. Producing acids (leucidic, branched acids) precursors to fruity esters. More specifically, and leaving aside the infrequent de novo formation, the action of the different strains of yeast on primary varietal aroma takes four different forms:

1.- Speeding the hydrolysis of aroma precursors, which leads to early aroma formation without changing the amount of aroma formed. In the case of labile molecules, such as linalool, the enhancement of young wine aroma implies a short-living wine. 2.- Metabolizing the aroma precursor, reducing the amounts of aroma formed, which can be of advantage for negative aroma compounds, such as TDN or guaiacol; 3.- Transforming grape components into aroma precursors, increasing the amounts of aroma formed, as for ethyl cinnamate, leucidic acid or vinylphenols; 4.- Forming reactive species such as vinylphenols able to destroy varietal polyfunctional mercaptans.

Overall, it can be concluded that the yeast carrying alcoholic fermentation not only influences fermentative wine aroma but also affects to the wine varietal aroma, to its evolution during aging and to the development of oxidative off-odors

The impact of vine pruning methods on physiological development and health condition of Vitis vinifera

This project aims on monitoring the plant development and comparison of the effects of various training systems on vine fertility and physiological processes.

α-Terpinyl ethyl ether: stereoselective GC × GC confirmation and identification of its precursors in wine

Wines exhibit profound chemical complexity which arise from a diverse array of compounds that contribute to its sensory profile.