Macrowine 2021
IVES 9 IVES Conference Series 9 Chemical and sensory diversity of regional Cabernet-Sauvignon wines

Chemical and sensory diversity of regional Cabernet-Sauvignon wines

Abstract

AIM: To investigate chemical and sensory drivers of regional typicity of Cabernet Sauvignon from different geographical regions of Australia.

METHODS: Commercial Cabernet wines (n = 52) from Coonawarra, Margaret River, and Yarra Valley Geographical Indications of Australia, and from Bordeaux, France, were selected for extensive chemical and sensory analysis.1 A range of analytical methods were optimised to quantify a comprehensive array of volatile compounds (> 70) originating from different sources, including grape, fermentation, oak maturation, and ageing. Along with basic chemical data, measurement of non-volatile compounds such as tannins and other secondary metabolites and elements was also undertaken. Multivariate statistical analysis using partial least squares regression was applied to the combined chemical data and the sensory analysis ratings obtained through a trained descriptive analysis panel of the same wines, to determine important compounds driving relevant sensory attributes.

RESULTS: The compound 1,4-cineole, described as ‘mint’ and ‘bay leaf’, was partly responsible for separation of the Cabernet Sauvignon wines from the Australian regions, particularly from Margaret River, whereas compounds such as 4-ethylphenol and 4-ethylguaiacol were linked to the aromas of ‘earthy’ and ‘yeasty’, which drove some of the separation of Bordeaux wines from the others. Varietal thiol, 3-mercapto-1-hexanol, which is mainly associated with Sauvignon Blanc and other white wine varieties, was measured in concentrations above its aroma detection threshold in all of the wines analysed, with similar concentrations present in Bordeaux and Coonawarra wines, and significantly higher concentrations in Margaret River and Yarra Valley wines. Additionally, non-volatiles such as particular elements drove some the separation between the regions; for example strontium was present in highest concentration in the Coonawarra wines and was found at lowest concentration in the Bordeaux wines. Free anthocyanins were also found to differ between Coonawarra and Bordeaux regions, with higher concentration being measured in the latter.

CONCLUSION

In determining the influential drivers of sensory properties of regional Cabernet Sauvignon wines, this study has uncovered various volatile and non-volatile constituents that are associated with specific sensory attributes. This is an important step in being able to define and subsequently help preserve the distinctive characters associated with regional Cabernet Sauvignon wines.

 

DOI:

Publication date: September 7, 2021

Issue: Macrowine 2021

Type: Article

Authors

Dimitra L. Capone 

Australian Research Council Training Centre for Innovative Wine Production, The University of Adelaide,Paul BOSS, CSIRO, and Australian Research Council Training Centre for Innovative Wine Production  Lira SOUZA GONZAGA, Australian Research Council Training Centre for Innovative Wine Production, and The University of Adelaide  Susan E. P. BASTIAN, Australian Research Council Training Centre for Innovative Wine Production, and The University of Adelaide Ruchira RANAWEERA, Department of Wine Science, The University of Adelaide David W. JEFFERY, Australian Research Council Training Centre for Innovative Wine Production, and The University of Adelaide

Contact the author

Keywords

volatile compound, non-volatile compound, sensory analysis, partial least squares regression, regionality, terroir

Citation

Related articles…

Denial of the wine-growing landscape

The aim of this presentation is to analysis the impact of the viticultural landscape in communication on labels of wine produced in heroic viticulture areas. To verify whether the ”viticultural landscape

Drought tolerance assessment and differentiation of grapevine cultivars using physiological metrics: insights from field studies

This study aimed to validate a protocol and compare metrics for evaluating drought tolerance in two Vitis vinifera grapevine cultivars under field conditions. Various metrics were calculated to represent the physiological responses of plants to progressive water deficit. Data were collected from Sauvignon Blanc and Chardonnay plants subjected to three irrigation levels during the 2022-2023 season, along with data from three previous seasons. Hydro-escape areas were used to assess the plant’s ability to reduce water potential with decreasing soil water availability.

Perception of Rose Oxide Enantiomers, Linalool and α-Terpineol to Gewürztraminer Wine Aroma

Monoterpenes are important aroma compounds in white wines. Many monoterpenes are chiral and the chiral forms have different aroma qualities.

Geospatial trends of bioclimatic indexes in the topographically complex region of Barolo DOCG

Barolo DOCG is an economically important wine producing region in Northwest Italy. It is a small region of approximately 70 km2 gross area. The topography is very complex with steep sloped hills ranging in elevation from below 200 m to 550 m. Barolo DOCG wine is made exclusively from the Nebbiolo grape. Bioclimatic indexes are often used in viticulture to gain a better understanding of broader climate trends which can be compared temporally and geographically. These indexes are also used for identifying potential phenological timing, growing region suitability, and potential risks associated with expected climatic changes. Understanding how topography influences bioclimatic indexes can help with understanding of mesoscale climate behaviour leading to improved decision making and risk management strategies. The average monthly maximum and minimum temperatures, the Cool Night Index, the Huglin Index, and the monthly diurnal range (from July to October) were calculated using data from 45 weather stations within a 40 km radius of the Barolo DOCG growing area between the years 1996 and 2019. Linear and multiple regression models were developed using independent variables (elevation, aspect, slope) extracted from a digital elevation model to identify significant relationships. Bioclimatic indexes were then kriged with external drift using independent variables that showed significant relationships with the bioclimatic index using a 100 m resolution grid. The maximum monthly temperatures and the Huglin Index showed consistent significant negative relationships with elevation in all years. The minimum monthly temperatures showed no relationship with elevation but in some months a small but significant relationship was observed with aspect. Due to the lack of a relationship between minimum monthly temperatures and elevation compared to the significant relationship between maximum monthly temperatures and elevation, monthly diurnal range had a negative relationship with elevation.

20-Year-Old data set: scion x rootstock x climate, relationships. Effects on phenology and sugar dynamics

Global warming is one of the biggest environmental, social, and economic threats. In the Douro Valley, change to the climate are expected in the coming years, namely an increase in average temperature and a decrease in annual precipitation. Since vine cultivation is extremely vulnerable and influenced by the climate, these changes are likely to have negative effects on the production and quality of wine.
Adaptation is a major challenge facing the viticulture sector where the choice of plant material plays an important role, particularly the rootstock as it is a driver for adaptation with a wide range of effects, the most important being phylloxera, nematode and salt, tolerance to drought and a complex set of interactions in the grafted plant.
In an experimental vineyard, established in the Douro Region in 1997, with four randomized blocs, with five varieties, Touriga Nacional, Tinta Barroca, Touriga Franca and Tinta Roriz, grafted in four rootstocks, Rupestris du Lot, R110, 196-17C, R99 and 1103P, data was collected consecutively over 20 years (2001-2020). Phenological observations were made two to three times a week, following established criteria, to determine the average dates of budbreak, flowering and veraison. During maturation, weekly berry samples were taken to study the dynamics of sugar accumulation, amongst other parameters. Climate data was collected from a weather station located near the vineyard parcel, with data classified through several climatic indices.
The results achieved show a very low coefficient of variations in the average date of the phenophases and an important contribution from the rootstock in the dynamic of the phenology, allowing a delay in the cycle of up to10-12 days for the different combinations. The Principal Component Analysis performed, evaluating trends in the physical-chemical parameters, highlighted the effect of the climate and rootstock on fruit quality by grape varieties.