Terroir 2004 banner
IVES 9 IVES Conference Series 9 Role of Harvesting Time/Optimal Ripeness in Zone/Terroir Expression

Role of Harvesting Time/Optimal Ripeness in Zone/Terroir Expression

Abstract

[English version below]

La maturité optimale est définie en fonction du style de vin désiré, qui est fonction du marché. Le sol et le climat ont un effet sur la typicité des vins. Le niveau qualitatif des raisins et des vins, et le potentiel pour obtenir différents styles de vin est déterminé par l’association des caractéristiques naturel du terroir et les technologies mises en œuvres (i.e. les pratiques culturales à moyen et long terme). Les conditions de culture de la vigne doivent permettre une activité optimale des racines, des structures pérennes, de la canopée, des grappes et favoriser l’équilibre entre ces organes jusqu’à l’objectif final : des raisins de qualités différentes pour des styles de vin différents. La gestion et l’analyse des paramètres morphologiques et physiologiques de la canopée et des grappes, dans un environnement donné, est indispensable pour trouver les indicateurs qui peuvent être associés à une qualité de raisin et un style de vin. Ce point n’a pas été systématiquement étudié.
Dans cet article, un bref rappel de l’impact potentiel du terroir et des pratiques culturales court et long terme sera donné. La partie principale indiquera les résultats d’une collaboration de recherche faite sur Syrah/99R dans un vignoble de la région de Stellenbosch, Afrique du Sud. L’objectif a été de définir les paramètres de l’environnement, de la canopée et des grappes utilisables comme indicateurs pratiques et pertinents de la qualité du raisin en relation avec un style de vin. Les vignes sont conduites en Espalier (2,75m x 1,5m), les rangs sont orientés nord – sud, le vignoble est en pente orientée est. Une irrigation par micro aspersion est appliquée de la nouaison à la véraison. La hauteur de végétation est de 1,4 m, avec 2 hauteurs de fils de palissage. Les vignes sont palissées et écimées. Des prélèvements ont été réalisés tous les 15 jours depuis la nouaison jusqu’à la véraison. A partir de la véraison (14°Brix) des prélèvements de raisin ont été réalisés tous les 4 jours et jusqu’à sur-maturation, pour réaliser des mini vinifications. A chaque stade de prélèvement les paramètres du microclimat ont été mesurés. L’évolution végétative, reproductive et physiologique de la plante a été étudiée. Les fermentations ont été contrôlées pour chaque mini-vinifications. Les vins ont été analysés. Les similitudes et les variations dans l’évolution des paramètres et leurs ratio ont été analysées et interprétées.
Les résultats sont discutés en relation avec la performance de la canopée, l’allocation de carbone, les relations avec l’état hydrique de la vigne, le rendement, ainsi que le contenu en sucre, en acides organiques, en anthocyanes, en phénols et en tanins totaux des baies. L’ensemble est corrélé à la qualité des vins et à leurs composition. Les ratios des indicateurs sont testés pour déterminer la qualité optimale du raisin et la date de vendange en relation avec le style de vin. La pertinence et l’applicabilité des indicateurs sont discutées.

Optimal ripeness is defined according to the style of wine that is required. The latter is ultimately dictated by the market. Soil and climate may have a dictating effect on typical expression of wine. The level of grape and wine quality achieved and the potential for obtaining different styles of wine are determined by the integrated effect of the natural characteristics of the terroir and technological intervention (long and short term cultivation practices). The growth conditions that the grapevine is subjected to should allow optimal metabolic activity in roots, permanent structure, canopy and grapes and the potential for these organs to develop and support each other until the desired grape quality and style is reached. Monitoring of morphological and physiological parameters in the canopy and grapes, ultimately displaying the integrated effect of the growth environment, is critical in our quest for finding indicators that may be associated with a particular grape and wine style. This has not been systematically investigated.
Results of collaborative research done on a Shiraz/R99 vineyard in the Stellenbosch region, South Africa, with the purpose of defining environmental, canopy and grape parameters that may be suitable as eventual practical indicators for obtaining particular styles of grapes and wine, are presented. Vines were vertically trellised and spaced 2.75 x 1.5 m in north-south orientated rows on a Glenrosa soil and a west-facing slope. Microsprinkler-irrigation was applied at pea berry size and at vèraison stages. The 1.4 m canopies were shoot-positioned and topped. Fortnightly sampling was done from berry set up to two weeks post-véraison, after which harvesting for wine making was done approximately every four days. Microclimate, vegetative, reproductive and physiological parameters were investigated and changes during alcoholic fermentation monitored at each harvesting stage. Wines were made and analysed. Similarities in patterns as well as various ratios between the different parameters were investigated. Results are argued against canopy performance, carbon allocation, water relations, production level, and sugar, acidity, anthocyanin, phenolic and tannin contents of the grapes as well as wine quality and composition. Ratios for potential practical use in determining optimal grape quality, time of harvesting and expected wine style are discussed.

DOI:

Publication date: January 12, 2022

Issue: Terroir 2004

Type: Article

Authors

J.J. Hunter (1), A. Pisciotta (2), C.G.Volschenk (1), E. Archer (3), V. Novello (4), E. Kraeva (5), A. Deloire (5), M. Nadal (6)

(1) ARC Infruitec-Nietvoorbij, Private Bag X5026, 7599 Stellenbosch, South Africa
(2) Dipartimento di Colture Arboree, Università degli Studi di Palermo, Viale delle Scienze 11, 90128 Palermo, Sicily, Italy
(3) Lusan Premium Wines, PO Box 104, 7599 Stellenbosch, South Africa
(4) Dipartimento di Colture Arboree, Via Leonardo da Vinci 44, I 10095 Grugliasco (TO), Italy
(5) Agro Montpellier, UMR 1083 « Sciences pour l’œnologie et la Viticulture », 2 place Viala, 34060 Montpellier cedex 1, France
(6) Departament de Bioquimica i Biotecnologia, Facultat d’Enologia de Tarragona, Ramón y Cajal 70, 43003 Tarragona, Spain

Contact the author

Keywords

Grapevine, Shiraz, physiology, grape composition, ripeness level, wine quality, wine style

Tags

IVES Conference Series | Terroir 2004

Citation

Related articles…

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.

Elucidating vineyard site contributions to key sensory molecules: Identification of correlations between elemental composition and volatile aroma profile of site-specific Pinot noir wines

The reproducibility of elemental profile in wines produced across multiple vintages has been previously reported using grapes from a single scion clone of Vitis vinifera L. cv. Pinot noir. The grapevines were grown on fourteen different vineyard sites, from Oregon to southern California in the U.S.A., which span distances from approximately hundreds of meters to 1450 km, while elevations range from near sea level to nearly 500 m. In addition, sensorial (i.e. aroma, taste, and mouthfeel) and chemical (i.e. polyphenolic and volatile) differences across the different vineyard sites have also been observed among these wines at two aging time points. While strong evidence exists to support that grapes grown in different regions can produce wines with unique chemical and sensorial profiles, even when a single clone is used, the understanding of growing site characteristics that result in this reproducible differentiation continues to emerge. One hypothesis is that the elemental profile that a vineyard site imparts to the grape berries and the resulting wine is an important contributor to this differentiation in chemistry and sensory of wines. For example, various classes of enzymes that catalyze the formation of key aroma compounds or their precursors require specific metals. In this work, we begin to report correlations between elemental and volatile aroma profiles of site-specific Pinot noir wines, made under standardized winemaking conditions, that have been previously shown to be distinguished separately by these chemical analyses.

Climate ethnography and wine environmental futures

Globalisation and climate change have radically transformed world wine production upsetting the established order of wine ecologies. Ecological risks and the future of traditional agricultural systems are widely debated in anthropology, but very little is understood of the particular challenges posed by climate change to viticulture which is seen by many as the canary in the coalmine of global agriculture. Moreover, wine as a globalised embedded commodity provides a particularly telling example for the study of climate change having already attracted early scientific attention. Studies of climate change in viticulture have focused primarily on the production of systematic models of adaptation and vulnerability, while the human and cultural factors, which are key to adaptation and sustainable futures, are largely missing. Climate experts have been unanimous in recognising the urgent need for a better understanding of the complex dynamics that shape how climate change is experienced and responded to by human systems. Yet this call has not yet been addressed. Climate ethnography, coined by the anthropologist Susan Crate (2011), aims to bridge this growing disjuncture between climate science and everyday life through the exploration of the social meaning of climate change. It seeks to investigate the confrontation of its social salience in different locations and under different environmental guises (Goodman 2018: 340). By understanding how wine producers make sense of the world (and the environment) and act in it, it proposes to focus on the co-production of interdisciplinary knowledge by identifying and foreshadowing problems (Goodman 2018: 342; Goodman & Marshall 2018). It seeks to offer an original, transformative and contrasted perspective to climate change scenarios by investigating human agency -individual or collective- in all its social, political and cultural diversity. An anthropological approach founded on detailed ethnographies of wine production is ideally placed to address economic, social and cultural disruptions caused by the emergence of these new environmental challenges. Indeed, the community of experts in environmental change have recently called for research that will encompass the human dimension and for more broad-based, integrated through interdisciplinarity, useful knowledge (Castree & al 2014). My paper seeks to engage with climate ethnography and discuss what it brings to the study of wine environmental futures while exploring the limitations of the anthropological environmental approach.

Modulation of berry composition by different vineyard management practices

High concentration of sugars in grapes and alcohol in wines is one of the consequences of climate change on viticulture production in several wine-growing regions. In order to investigate the possibilities of adaptation of vineyard management practices aimed to reduce the accumulation of sugar during the maturation phase without reducing the accumulation of anthocyanins in grapes, a study with severe shoot trimming, shoot thinning, cluster thinning and date of harvest was conducted on Merlot variety in Istria region (Croatia), under the Mediterranean climate. Four factors which may affect grape maturation and its composition at harvest were investigated in a two-years experiment; severe shoot trimming applied at veraison when >80% of berries changed colour (in comparison to untreated control), shoot thinning (0 and 30%), cluster thinning (0 and 30%), and the date of harvest (early and standard harvest dates). Shoot thinning had no significant impact on berry composition, despite the obtained reduction in yield per vine. Lower Brix in grapes were obtained with earlier harvest date and if no cluster thinning was applied, although at the same time a reduction in the concentration of anthocyanins in berries was observed in these treatments. On the other hand, if severe shoot trimming was applied when >80% of berries changed colour, a reduction of Brix was obtained without a negative impact on berry anthocyanins concentration. We conclude that in cases when undesirably high sugar concentrations at harvest are expected, severe shoot trimming at 80% veraison may effectively be used in order to obtain moderate sugar concentration in berries together with the adequate phenolic composition.

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.