IVAS 2022 banner
IVES 9 IVES Conference Series 9 IVAS 9 IVAS 2022 9 Chenin Blanc Old Vine character: evaluating a typicality concept by data mining experts’ reviews and producers’ tasting notes

Chenin Blanc Old Vine character: evaluating a typicality concept by data mining experts’ reviews and producers’ tasting notes

Abstract

Concepts such as typicality are difficult to demonstrate using the limited set of samples that can be subjected to sensory evaluation. This is due both to the complexity of the concept and to the limitations of traditional sensory evaluation (number of samples per session, panel fatigue, the need for multiple sessions and methods, etc.). On the other hand, there is a large amount of data already available, accumulated through many years of consistent evaluation. These data are held in repositories (such as Platter’s Wine Guide in the case of South Africa Wine, wineonaplatter.com) and in technical notes provided by the producers.There are many unknowns regarding the distinguishing features of a commercial Old Vine (OV) Chenin Blanc wine and its comparison to a Young Vine (YV) wine. There is little work done on it and the work has limitations regarding the methodology and number of samples included (Crous, 2016; Mafata, Brand, Panzeri, et al., 2020). Platter’s data contains descriptors for wines produced in South Africa, as well as a quality rating. The producers put technical sheets together – while the expert tasters generate Platter’s data for the same wines.Similar to work done on the general characteristics of South African Chenin Blanc wine (Valente, Bauer, Venter, et al., 2018), the goal of the study is to find the unique features associated with the ‘old vine Chenin Blanc character’ using available data from expert tastings and technical notes. During the initial step, Platter’s data and technical notes are mined for attributes of Chenin Blanc wines (as both sources indicate whether the wines belong to the Old Vine category). The automated process is done using the data gathering and analysis tool developed by the research team. A combined data set from all data sources is also  created.During the analysis step, Agglomerative Hierarchical Clustering (AHC), Multiple Correspondence Analysis (MCA), Fuzzy K-Means clustering (FKM), and Formal Concept Lattice (FCL) are employed to explore the attribute and product space. Clustering algorithms are applied to the data (separate and fused sets) to identify markers (features) for the Old Vine character. As Platter’s data also includes product ratings, the possible correlation of Old Vines vs. Young Vines regarding the perceived quality can also be tested. In addition to finding sensory attributes associated exclusively with Old Vine Chenin Blanc (the typicality issue), the novelty of the work also resides with the creation and development of a new application for the automated data gathering and analysis tool, whose effectiveness and robustness will be tested in the real case scenario.

References

Crous, R. 2016. The sensory characterisation of old-vine Chenin blanc wine: an exploratory study of the dimensions of quality. Stellenbosch University.
Mafata, M., Brand, J., Panzeri, V. & Buica, A. 2020. Investigating the Concept of South African Old Vine Chenin Blanc. South African Journal of Enology and Viticulture. 14(2):168–182.
Valente, C.C., Bauer, F.F., Venter, F., Watson, B. & Nieuwoudt, H.H. 2018. Modelling the sensory space of varietal wines: Mining of large, unstructured text data and visualisation of style patterns. Scientific Reports. 8(1).

DOI:

Publication date: June 27, 2022

Issue: IVAS 2022

Type: Poster

Authors

Kruger Markus1, Brand J.1, Watson B.2, Mafata M.1 and Buica A.1

1Department of Information Science, Stellenbosch University, South Africa; South African Grape and Wine Research Institute, Department of Viticulture and Oenology, Stellenbosch University, South Africa
2 Department of Information Science, Stellenbosch University, South Africa

Contact the author

Keywords

Chenin Blanc, Old Vine, Automation, Multi-source data gathering

Tags

IVAS 2022 | IVES Conference Series

Citation

Related articles…

Pruned vine biomass exclusion from a clay loam vineyard soil – examining the impact on physical/chemical properties

The wine industry worldwide faces increasing challenges to achieve sustainable levels of carbon emission mitigation. This project seeks to establish the feasibility of harvesting winter pruned vineyard biomass (PVB) for potential use in carbon footprint reduction, through its use as a renewable biofuel for energy production. In order to make this recommendation, technical issues such as the potential environmental impact, chemical composition and fuel suitability, and logistical challenges of harvesting biomass needs to be understood to compare with the results from similar studies. Of particular interest is the role PVB plays as a carbon source in vineyard soils and what effect annual removal might have on soil carbon sequestration. A preliminary trial was established in the Waite Campus vineyard (University of Adelaide) to test current management strategies. Vines are grown in a Eutrophic, Red Dermosol clay loam soil with well managed midrow swards. A comparison was undertaken of mid-row treatments in two 0.25 Ha blocks (Shiraz and Semillon), including annual cultivation for seed bed preparation, the deliberate exclusion of PVB (25 years) and incorporation of PVB (13 years) at an average of 3.4 and 5.5 Mg/Ha-1 for Shiraz and Semillon respectively. In both 0-10cm and 10-30cm soil core sample depths, combined soil carbon % measures in the desired range of 1.80 to 3.50, were not significantly different between treatments or cultivars and yielded an estimated 42 Mg/ha-1 of sequestered soil carbon. Other key physical and chemical measures were likewise not significantly different between treatments. Preliminary results suggest that in a temperate zone vineyard, managed such as the one used in this study, there is no long term negative impact on soil carbon sequestration through removing PVB. This implies that growers could confidently harvest PVB for use in several end fates including as a bio fuel.

austrianvineyards.com: online viewer of all designations of Austrian wine

To digitally record and present all the origins of Austrian wines in the same perfect and clear way was the motivation for the Austrian Wine Marketing Board (Austrian Wine) to start with the project in 2018. In June 2021 the results were presented to the public in an online viewer showing all the designations of Austrian wine, available at https://austrianvineyards.com in a largely barrier-free manner. The online viewer provides tailored individual maps fitted to the respective zoom level. The smallest unit of wine-origins in Austria is called Ried and is displayed in a plot-specific manner highlighting areas under vine. Information on the Ried include administrative district, winegrowing municipality, cadastral municipality, large collective vineyard site, specific winegrowing region, generic winegrowing region, winegrowing area and, in many cases, an illustrative picture. Complementary data on the size, elevation (minimum-maximum), orientation (in 8 sectors plus flat) and gradient (minimum, maximum, average) are based on the area under vine according to the EU’s Integrated Administration and Control System. Additional information covers climate data. The diagrams are taken from the monthly breakdown of data in the annals of the Central Institute for Meteorology and Geodynamics, Austria provide a display of values for air temperature, precipitation, and sunshine hours for the reference year and the long-term average. Seasonal aggregated data on temperature, precipitation, and sunshine hours complete the display. Short descriptions with emphasis on geology and soil, field name in historical maps, etymology of the denomination, and main planted variety complements the available information for the main designations in the online viewer. These descriptions are compiled by winegrowers, geologists, historians, and journalists. All the information and data can be extracted to a pdf-file. Printed vineyard maps are also available. Missing content regarding wine origins in Styria will be completed in winter 2021/22.

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.

Amino nitrogen content in grapes: the impact of crop limitation

As an essential element for grapevine development and yield, nitrogen is also involved in the winemaking process and largely affects wine composition. Grape must amino nitrogen deficiency affects the alcoholic fermentation kinetics and alters the development of wine aroma precursors. It is therefore essential to control and optimize nitrogen use efficiency by the plant to guarantee suitable grape nitrogen composition at harvest. Understanding the impact of environmental conditions and cultural practices on the plant nitrogen metabolism would allow us to better orientate our technical choices with the objective of quality and sustainability (less inputs, higher efficiency). This trial focuses on the impact of crop limitation – that is a common practice in European viticulture – on nitrogen distribution in the plant and particularly on grape nitrogen composition. A wide gradient of crop load was set up in a homogeneous plot of Chasselas (Vitis vinifera) in the experimental vineyard of Agroscope, Switzerland. Dry weight and nitrogen dynamics were monitored in the roots, trunk, canopy and grapes, during two consecutive years, using a 15N-labeling method. Grape amino nitrogen content was assessed in both years, at veraison and at harvest. The close relationship between fruits and roots in the maintenance of plant nitrogen balance was highlighted. Interestingly, grape nitrogen concentration remained unchanged regardless of crop load to the detriment of the growth and nitrogen content of the roots. Meanwhile, the size and the nitrogen concentration of the canopy were not affected. Leaf gas exchange rates were reduced in response to lower yield conditions, reducing carbon and nitrogen assimilation and increasing intrinsic water use efficiency. The must amino nitrogen profiles could be discriminated as a function of crop load. These findings demonstrate the impact of plant balance on grape nitrogen composition and contribute to the improvement of predictive models and sustainable cultural practices in perennial crops.

Simulating climate change impact on viticultural systems in historical and emergent vineyards

Global climate change affects regional climates and hold implications for wine growing regions worldwide. Although winegrowers are constantly adapting to internal and external factors, it seems relevant to develop tools, which will allow them to better define actual and future agro-climatic potentials. Within this context, we develop a modelling approach, able to simulate the impact of environmental conditions and constraints on vine behaviour and to highlight potential adaptation strategies according to different climate change scenarios. Our modeling approach, named SEVE (Simulating Environmental impacts on Viticultural Ecosystems), provides a generic modeling framework for simulating grapevine growth and berry ripening under different conditions and constraints (slope, aspect, soil type, climate variability…) as well as production strategies and adaptation rules according to climate change scenarios. Each activity is represented by an autonomous agent able to react and adapt its reaction to the variability of environmental constraints. Using this model, we have recently analyzed the evolution of vineyards’ exposure to climatic risks (frost, pathogen risk, heat wave) and the adaptation strategies potentially implemented by the winegrowers. This approach, implemented for two climate change scenarios, has been initiated in France on traditional (Loire Valley) and emerging (Brittany) vineyards. The objective is to identify the time horizons of adaptations and new opportunities in these two regions. Carried out in collaboration with wine growers, this approach aims to better understand the variability of climate change impacts at local scale in the medium and long term.