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…

How can historical cultivars mitigate the effects of climate change?

IFV, INRAe and the national network “Partenaires de la Sélection Vigne” representing 37 organizations from the different wine regions, have been working increasingly closely over the last 2 decades towards the preservation of the French varietal patrimony. There are approximately 600 patrimonial varieties according to INRAe and SupAgro Montpellier experts, including ancient cultivars (400) and intravarietal crossbreeds obtained since the 19th century. In the context of a drastic reduction in such varieties from the mid 1980’s in favor of mainstream varieties, it was essential to carry out an inventory of old vines and vineyards. INRAe Vassal collection plays a key role here as it holds the largest diversity available, along with a rich bibliography and herbariums, offering us the opportunity to document and double check the identity of a cultivar, consolidating the expertise of ampelographers. The work is carried out in several stages, from verifying the existence of a variety in a small region, through to rehabilitation. During this session, the authors present the process that leads to the official registration of a variety. After this, IFV selection center takes over to initiate the process of selection and propagation. A specific focus within regions such as the Alps, Champagne and the South-West will provide details of the full procedure. Bia, Bouysselet, Chardonnay rose, Mecle and the aptly named Tardif, are some of the cultivars that have followed this procedure. Furthermore, a recent regulation established by INAO on “varieties of interest for adaptation purposes” might boost uptake by growers. Since 2006, 36 historical cultivars have been registered. Most of these have been neglected in the past due to late maturity, lack of sugar and high titratable acidity at harvest time. Such characteristics are today considered as positive qualities, not only in mitigation of the effects of climate change, but also as an opportunity for restoring diversity…

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.

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.

Impact of climate variability and change on grape yield in Italy

Viticulture is entangled with weather and climate. Therefore, areas currently suitable for grape production can be challenged by climate change. Winegrowers in Italy already experiences the effect of climate change, especially in the form of warmer growing season, more frequent drought periods, and increased frequency of weather extremes.
The aim of this study is to investigate the impact of climate variability and change on grape yield in Italy to provide winegrowers the information needed to make their business more sustainable and resilient to climate change. We computed a specific range of bioclimatic indices, selected by the International Organisation of Vine and Wine (OIV), and correlated them to grape yield data. We have worked in collaboration with some wine consortiums in northern and central Italy, which provided grape yield data for our analysis.
Using climate variables from the E-OBS dataset we investigate how the bioclimatic indices changed in the past, and the impact of this change on grape productivity in the study areas. The climate impact on productivity is also investigated by using high-resolution convection-permitting models (CPMs – 2.2 horizontal resolution), with the purpose of estimating productivity in future emission scenarios. The CPMs are likely the best available option for this kind of impact studies since they allow a better representation of small-scale processes and features, explicitly resolve deep convection, and show an improved representation of extremes. In our study, we also compare CPMs with regional climate models (RCMs – 12 km horizontal resolution) to assess the added value of high-resolution models for impact studies. Further development of our study will lead to assessing the future suitability for vine cultivation and could lead to the construction of a statistical model for future projection of grape yield.

A blueprint for managing vine physiological balance at different spatial and temporal scales in Champagne

In Champagne, the vine adaptation to different climatic and technical changes during these last 20 years can be seen through physiological balance disruptions. These disruptions emphasize the general grapevine decline. Since the 2000s, among other nitrogen stress indicators, the must nitrogen has been decreasing. The combination of restricted mineral fertilizers and herbicide use, the growing variability of spring rainfall, the increasing thermal stress as well as the soil type heterogeneity are only a few underlying factors that trigger loss of physiological balance in the vineyards. It is important to weigh and quantify the impact of these factors on the vine. In order to do so, the Comité Champagne uses two key-tools: networking and modelization. The use of quantitative and harmonized ecophysiological indicators is necessary, especially in large spatial scales such as the Champagne appellation. A working group with different professional structures of Champagne has been launched by the Comité Champagne in order to create a common ecophysiology protocol and thus monitor the vine physiology, yearly, around 100 plots, with various cultural practices and types of soil. The use of crop modelling to follow the vine physiological balance within different pedoclimatic conditions enables to understand the present balance but also predict the possible disruptions to come in future climatic scenarios. The physiological references created each year through the working group, benefit the calibration of the STICS model used in Champagne. In return, the model delivers ecophysiology indicators, on a daily scale and can be used on very different types of soils. This study will present the bottom-up method used to give accurate information on the impacts of soil, climate and cultural practices on vine physiology.