 IVES 9 IVES Conference Series 9 Shades of shading: chemical and sensory evaluation of riesling grown under various shading techniques

Shades of shading: chemical and sensory evaluation of riesling grown under various shading techniques

Abstract

AIM: Sun exposure is needed for balanced grape ripening and sugar accumulation but is also one of the main drivers for a premature Riesling ageing. The aim of this study was to evaluate the modulation of both intensity and quality of light in the vineyard on key Riesling grape and wine parameters as an adaptation strategy to changing climate. Of particular interest was the kerosene aroma caused by the C13‑norisoprenoid TDN and other compounds associated with light-induced grape compositional changes.

METHODS: Over two vintages shade cloth of three different colours was applied to Riesling vines at bunch zone in South Australia. Light measurements and incident light wavelength assessments were performed during grape ripening, and subsequent grapes and wine were analysed for key bound and free aroma compounds. After 1-year of storage, wines were analysed by Quantitative Descriptive Analysis to quantify the holistic changes of light modulation to the sensory profile.

RESULTS: Depending on colour, shade cloth was successful in modulating either the quantity and/or wavelength of light, as well as showed different response of sugar accumulation. Shading reduced TDN concentrations and kerosene aroma in wines, with very little effect on other sensory descriptors. Interestingly, while presumed C13-norisoprenoid precursor profiles were altered between shading treatments, no significant differences were observed in resulting TDN levels.

CONCLUSIONS

This study highlights the importance of light intensity over examined light wavelength in the vineyard to manipulate TDN. Additionally, light conditions differently affected maturity with possible implications for harvest timing and climate-induced vintage compression.

DOI:

Publication date: September 13, 2021

Issue: Macrowine 2021

Type: Article

Authors

Yevgeniya Grebneva

The Australian Wine Research Institute & the Department of Microbiology and Biochemistry, Hochschule Geisenheim University,Markus, HERDERICH, The Australian Wine Research Institute, Adelaide 5064, Australia Doris, RAUHUT, Department of Microbiology and Biochemistry, Hochschule Geisenheim University Eleanor, BILOGREVIC, The Australian Wine Research Institute, Adelaide 5064, Australia Josh, HIXSON, The Australian Wine Research Institute, Adelaide 5064, Australia

Contact the author

Keywords

riesling, norisoprenoid, tdn, shade cloth

Citation

Selected ion flow tube mass spectrometry: a promising technology for the high throughput phenotyping of grape berry volatilome

Wine grapes breeding has been concentrating a lot of efforts within the grape research community over the last decade. The quick phenotyping of genotype quality traits including aroma composition remains challenging. Selected Ion Flow Tube Mass Spectrometry (SIFT-MS), a technology first available in 2008 and developing rapidly, could be particularly valuable for this usage. The aims of this study were i) to use SIFT-MS, to analyze the whole volatilome from different grape varieties, ii) to assess the ability of this technology to discriminate varieties according to their grape aroma composition, and iii) to study the stability of SIFT-MS signal over maturation to define a sampling strategy.

Improvement of the red wine AOC Grignolino d’Asti typicality using some technological innovations

L’AOC Grignolino d’Asti (20000 hl environ de production) est un vin de la province de Asti, produit avec le raisin rouge du cépage de même nom originaire du Piémont (Nord-Ouest d’Italie).

Eugenol: a new marker of hybrid vines? The case study of Baco Blanc in Armagnac

Nowadays, winemaking is dealing with great challenges, notably climate change, disease resistance and low pesticide inputs, desire for more sustainable agricultural productions and permanent changing of consumer preference. Trying to propose practice improvements, scientists are exploring vine hybridization a paradoxically old but still actual way to take up such challenges

The effect of cropload on the volatile aroma characteristics of ‘Beihong’ and ‘Beimei’ red wine

Beihong and Beimei were bred as winemaking cultivars released by Institute of Botany, the Chinese Academy of Sciences in 2008. The cultivars are selected from the population of ‘Muscat Hamburg’ (Vitis vinifera) ×V. amurensis. They are extended to most provinces in North of China because they have strong resistance to cold and disease and need not be buried in soil in winter. To better understand the effect of cropload on volatile compounds during wine-making, we surveyed volatiles composition and content of different cropload level in 3-years-old ‘Beihong’ and ‘Beimei’ vines which planted in east foot of Helan mountain of Ningxia (EHN).

The modification of cultural practices in grapevine cv. Syrah, does it modify the characteristics of the musts?

The work shows the results of a year of experimentation (2020) in a Syrah variety vineyard in La Roda (Castilla-La Mancha, Spain). The trial approach was on a randomized block design with two factors: Irrigation (I) and Pruning (P).
Irrigation schedules were adjusted to apply amounts close to 1,500 m3/ha. With this provision, 2 different irrigation treatments were proposed: I1) Start of irrigation from pea-sized grape to post-harvest (providing at least 20 % of the total amount of irrigation water to be provided post-harvest); I2) Start of irrigation from pea-sized grape to harvest (usual irrigation practice in the study area). Pruning was proposed with two treatments, one at the end of January (P1), which is pruning on a conventional date; and P2) pruning carried out at the beginning of budding. In total, 4 repetitions were designed with 4 elementary plots, each one of them representing one of the proposed treatments (I1P1; I1P2; I2P1; I2P2). In total, 16 plots were worked on and each elementary plot consisted of 30 strains, distributed in 3 lines.
The productive response was evaluated with the yield results of the harvest harvested at 23 ºBrix. The qualitative response was measured in the musts through the indices of technological (acidity, pH and potassium) and phenolic maturity and aromatic compounds in free and glycosylated fractions. The treatments tested had, in general, an effect on the different variables analyzed.