GiESCO 2019 banner
IVES 9 IVES Conference Series 9 GiESCO 9 GiESCO 2019 9 Grape ripening and wine style: synchronized evolution of aromatic composition of shiraz wines from hot and temperate climates of Australia

Grape ripening and wine style: synchronized evolution of aromatic composition of shiraz wines from hot and temperate climates of Australia

Abstract

Context and purpose of the study ‐ Grape ripening is a process driven by the interactions between grapevine genotypes and environmental factors. Grape composition is largely responsible for the production and final concentrations of most wine aroma compounds even though many compounds in wines (aromatic and non‐aromatic) are substantially transformed during fermentation and wine ageing. The aim of this study was to investigate if a common pattern in grape/wine flavour plasticity related to ripening exists irrespective of a grape growing region. A further aim was to identify and highlight compounds present in Shiraz grapes and wines in which plasticity is directly related to grape ripening and is consistent over several vintages.

Material and methods ‐ Commercial vineyards of Shiraz were chosen in two Australian wine geographical indication (GI) regions: Griffith (warm to hot climate) and Orange (temperate to temperate‐warm climate). In these vineyards, own rooted vines were grown under drip irrigation, and trellised to a sprawling training system and in vertical shoot positioning for Orange. Sequential harvests were performed using berry sugar accumulation as a physiological indicator of grape maturity. At each harvest date, triplicates of 100 berries were collected and frozen in liquid nitrogen in the field for later chemical analyses. Approximately 60 kg of grape per replicate were randomly harvested at each harvest date and small scale vinifications carried out. Amino acids in grapes were analysed by high performance liquid chromatography (HPLC) coupled to fluorescence detector. Grape volatiles analyses were performed with gas chromatography coupled to mass detection (GC‐MS). Juice was analysed for set of parameters relating to the technical maturity of grapes (total soluble solids, titratable acidity and pH) and yeast assimilable nitrogen was measured. Wine aromatic compounds were quantitated by HS‐SPME‐GC‐MS. Descriptive sensory evaluation with predefined descriptors was conducted approximately six months after bottling.

Results ‐ Irrespective of the macro and meso climates, differences in both grape and wine chemical analyses and wine sensory description produced a clear separation of samples according to the harvest stage. Shiraz wines from the first harvest (H1) were associated with red fruit descriptors and higher perception of acidity. Wines from the third harvest (H3) were correlated with dark fruit characters and a higher alcohol. Later harvest dates resulted in higher concentrations of some amino acids in the Shiraz grapes, with higher alcohol acetates, ethyl esters (ethyl propanoate and ethyl butyrate) of short chain fatty acids and dimethyl sulphide in the wines. Conversely, concentrations of (Z)-3‐hexenol, ethyl isobutyrate, ethyl leucate and ethyl dihydrocinammate were lower in these wines compared to earlier harvest dates. Observed trends were significant and consistent across two vintages and two different GIs. From the plateau of berry sugar accumulation, no direct nexus was observed between berry sugar concentration and grape and wine flavour evolution. This study also demonstrated a common evolution of Shiraz grapes, influencing the chemical and sensory properties of the subsequent wine.

DOI:

Publication date: June 19, 2020

Issue: GiESCO 2019

Type: Article

Authors

Katja ŠUKLJE (1,3), Guillaume ANTALICK (1,4), Campbell MEEKS (1), John BLACKMAN (1,2), Alain DELOIRE (1,5), Leigh SCHMIDTKE (1,2)

(1) National Wine and Grape Industry Centre, Charles Sturt University, Locked Bag 588, Wagga Wagga, NSW 2678, Australia
(2) School of Agricultural and Wine Sciences, Charles Sturt University, Locked Bag 588, Wagga Wagga, NSW 2678, Australia
Present addresses: 3 Hacquetova 17, 1000 Ljubljana,
(4) Wine research centre, University of Nova Gorica, Glavni trg 8, 5271 Vipava, Slovenia
(5) Montpellier SupAgro‐IHEV‐BE, 2 Place Pierre Viala, 34060 Montpellier, France

Contact the author

Keywords

Grapevine, Australia, Shiraz, warm and temperate climates, sequential harvests, fruit and wine composition, sensory analyses

Tags

GiESCO 2019 | IVES Conference Series

Citation

Related articles…

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.

Adaptation to soil and climate through the choice of plant material

Choosing the rootstock, the scion variety and the training system best suited to the local soil and climate are the key elements for an economically sustainable production of wine. The choice of the rootstock/scion variety best adapted to the characteristics of the soil is essential but, by changing climatic conditions, ongoing climate change disrupts the fine-tuned local equilibrium. Higher temperatures induce shifts in developmental stages, with on the one hand increasing fears of spring frost damages and, on the other hand, ripening during the warmest periods in summer. Expected higher water demand and longer and more frequent drought events are also major concerns. The genetic control of the phenotypes, by genomic information but also by the epigenetic control of gene expression, offers a lot of opportunities for adapting the plant material to the future. For complex traits, genomic selection is also a promising method for predicting phenotypes. However, ecophysiological modelling is necessary to better anticipate the phenotypes in unexplored climatic conditions Genetic approaches applied on parameters of ecophysiological models rather than raw observed data are more than ever the basis for finding, or building, the ideal varieties of the future.

Permanent cover cropping with reduced tillage increased resiliency of wine grape vineyards to climate change

Majority of California’s vineyards rely on supplemental irrigation to overcome abiotic stressors. In the context of climate change, increases in growing season temperatures and crop evapotranspiration pose a risk to adaptation of viticulture to climate change. Vineyard cover crops may mitigate soil erosion and preserve water resources; but there is a lack of information on how they contribute to vineyard resiliency under tillage systems. The aim of this study was to identify the optimum combination of cover crop sand tillage without adversely affecting productivity while preserving plant water status. Two experiments in two contrasting climatic regions were conducted with two cover crops, including a permanent short stature grass (P. bulbosa hybrid), barley (Hordeum spp), and resident vegetation under till vs. no-till systems in a Ruby Cabernet (V. vinifera spp.) (Fresno) and a Cabernet Sauvingon (Napa) vineyard. Results indicated that permanent grass under no-till preserved plant available water until E-L stage 17. Consequently, net carbon assimilation of the permanent grass under no-till system was enhanced compared to those with barley and resident vegetation. On the other hand, the barley under no-till system reduced grapevine net carbon assimilation during berry ripening that led to lower content of nonstructural carbohydrates in shoots at dormancy. Components of yield and berry composition including flavonoid profile at either site were not adversely affected by factors studied. Switching to a permanent cover crop under a no-till system also provided a 9% and 3% benefit in cultural practices costs in Fresno and Napa, respectively. The results of this work provides fundamental information to growers in preserving resiliency of vineyard systems in hot and warm climate regions under context of climate change.

Biodiversity in the vineyard agroecosystem: exploring systemic approaches

Biodiversity conservation and restoration are essential for guarantee the provision of ecosystem services associated to vineyard agroecosystem such as climate regulation trough carbon sequestration and control of pests and diseases. Most of published research dealing with the complexity of the vineyard agroecosystems emphasizes the necessity of innovative approaches, including the integration of information at different temporal and spatial scales and development of systemic analysis based on modelling. A biodiversity survey was conducted in the Franciacorta wine-growing area (Lombardy, Italy), one of the most important Italian wine-growing regions for sparkling wine production, considering a portion of the territory of 112 ha. The area was divided into several Environmental Units (EUs), defined as a whole vineyard or portion of vineyard homogenous in terms of four agronomic characteristics: planting year, planting density, cultivar, and training system. In each EU a set of compartments was identified and characterised by specific variables. The compartments are meteorology, morphology (altitude, slope, aspect, row orientation, and solar irradiance), ecological infrastructures and management. The landscape surrounding EU was also characterised in terms of land-use in a buffer zone of 500 m. For each component a specific methodology was identified and applied. Different statistical approaches were used to evaluate the method to integrate the information related to different compartments within the EU and related to the buffer zone. These approaches were also preliminarily evaluated for their ability to describe the contribution of biodiversity and landscape components to ecosystem services. This methodological exploration provides useful indication for the development of a fully systemic approach to structural and functional biodiversity in vineyard agroecosystems, contributing to promote a multifunctional perspective for the all wine-growing sector.

How distinctive are single vineyard Gewürztraminer musts and wines from Alto Adige (Italy) based on untargeted analysis, sensory profiling, and chemometric elaboration?

Vitis vinifera L. ‘Gewürztraminer’ is a historical grape variety of Alto Adige (Südtirol), Italy, which is widely grown in the area of Tramin an der Weinstraße, but is also grown globally. It produces highly aromatic wines that are strongly influenced by the terroir of the vineyard sites where they are grown. This study looked at musts and young wines from ‘Gewürztraminer’ grapes harvested in seven distinct vineyards near Tramin and then processed at Cantina di Termeno, minimizing winemaking protocol variability. Samples were profiled using bidimensional gas chromatography–time-of-flight mass spectrometry, liquid chromatography coupled to electrochemical detection, and near-IR spectrometry. The data were subjected to Principle Component Analysis and Hierarchical Clustering Analysis. Sensory discriminant testing was undertaken using the sorting method with a semi-trained panel, and the data were processed using Multidimensional Scaling. Seven must/wine pairs could be distinguished based on their untargeted volatilome profiles and on sensory evaluation. As expected, there were greater differences in the volatile compounds between the wines than between the musts. The wines from vineyards 4 and 5 were nonetheless quite homogenous in terms of chemical and sensory analyses, as were the wines from vineyards 1 and 3. For the phenolic profile, differences were noted between the musts and wines of vineyards 2, 3, and 4, but the musts from vineyards 5 and 7 were similar. Sensory analysis showed the wines from vineyards 6 and 7 to be distinct from the rest. These results reinforce that the composition of ‘Gewürztraminer’ musts and wines is strongly determined by vineyard site, even in a small geographic area with high variability of the terroir (soil and microclimate), and that these differences are apparent in the flavours and aromas of the finished wines. Further confirmation would require a larger sample of wines, preferably from several vintages.