 IVES 9 IVES Conference Series 9 Gamay and Gamaret winemaking processes using stems: impact on the wine chemical and organoleptic characteristics

Gamay and Gamaret winemaking processes using stems: impact on the wine chemical and organoleptic characteristics

Abstract

AIM: Stalks are empirically known to bring many benefits to the wine such as alcoholic reduction, color protection or improvement of the tannic intensity. Not much used on Swiss grape varieties, the aim of this study was to identify the relevance of using this type of winemaking in the case of Gamay and Gamaret red grape varieties.

METHODS: Gamay and Gamaret grapes from a vineyards in Gland (Switzerland) were harvested and treated according to three modalities: fully destemmed used as control, 20% and 40% either whole grapes or stems added to the rest of the destemmed harvest. The influence of the stalks on the wine organoleptic properties was measured using different classical FTIR and colorimetric methods (alcohol, acidity, pH, SO2 …). Polyphenol content was evaluated using spectrophotometer measurements and concentration of flavanols and proanthocyanins in wine samples determined by HPLC-FLD-MS/MS. Sensory analysis were also performed in order to measure the impact on the wines.

RESULTS: Results showed that the total polyphenolic content was lower for trials with non-destemmed grapes and higher for the ones where stems were added. According to the tannin content, no significant differences were found between the modalities for the gamay grape variety. For the gamaret grape variety, the values were lower than the control when 20% and 40% of non-destemmed grapes were used. Planned sensory analysis should allow us to know the impact on the aromatic characters of these wines.

CONCLUSIONS:

This study allows us to acquire knowledge about winemaking processes performed using non-destemmed grapes and their impact on the wine characteristics. Both chemical composition and organoleptic characterization were taken into account

DOI:

Publication date: September 7, 2021

Issue: Macrowine 2021

Type: Article

Authors

Marie Blackford, Janina IMHOF 2, Julie ROESLE-FUCHS 2, Fabrice LORENZINI 1, Gilles BOURDIN 1, Benoit BACH 2

Marie Blackford – 1. AGROSCOPE , Nyon, Switzerland 2. Changins, Viticulture and oenology, HES-SO University of Applied Sciences and Arts Western Switzerland, Route de Duillier 50, 1260 Nyon 1, Switzerland ,Montaine COMBY 1,2, Janina IMHOF 2, Julie ROESLE-FUCHS 2, Ágnes DIENES-NAGY 1, Fabrice LORENZINI 1, Gilles BOURDIN 1, Benoit BACH 2 1 AGROSCOPE , Nyon, Switzerland 2 Changins, Viticulture and oenology, HES-SO University of Applied Sciences and Arts Western Switzerland, Route de Duillier 50, 1260 Nyon 1, Switzerland

Contact the author

Keywords

stem, whole cluster, winemaking, polyphenols

Citation

EFFECTS OF WINEMAKING FACTORS AND AGEING ON THE POLYPHENOLIC AND COLORIMETRIC PROFILES IN RED WINES PRONE TO COLOUR INSTABILITY

The effects of (A) grape freezing, and (B) malolactic fermentation, have been evaluated on the chemical and colorimetric profiles of red wines from Schiava grossa cv. grapes, thus prone to colour instability. The aim was to observe if specific variables (e.g. grape freezing) could improve the extraction and stability of pigments. The samples were studied from musts up to twelve months in bottle. The study was conducted with independent parallel micro-vinifications (12 = 4 theses x 3 replicates) under strictly-controlled conditions.

Do we have convergence or divergence in firms’ production and business practices in the global wine industry?

Wine production is a globally significant and intricate industry, characterized by diverse regions, grape varieties, and producers. Competitive advantage in wine production and marketing arises from localized natural attributes known as terroir, combined with transferable expertise in agronomic practices, winemaking methods, packaging, distribution, and marketing. Wine is a very globalized product with 40% of the total output exported. Globalization has prompted discussions on convergence of business and production practices across industries, driven by technological progress and adoption of international standards. However, persisting differences in cultural norms, institutional frameworks, and regulatory environments hinder full convergence.

Soil humidity and early leaf water potential affected by water recharge before budbreak in cv. Tempranillo deficitary irrigated during the summer in the D. O. Ribera del Duero

The availability of water for irrigation is usually greater at the beginning of spring than in the following months, until the end of summer, in most regions of Spain.

Estimation of stomatal conductance and chlorophyll fluorescence in Croatian grapevine germplasm under water deficit

Water deficit profoundly impacts the quality of grapes and results in considerable reductions in crop yield. First symptoms manifest with reduced stomatal conductance and transpiration, accompanied by the wilting of apical leaves and tendrils. So far, there is no available data on the water stress response in Croatian grapevine germplasm. Therefore, objective of this study was to determine influence of genotype and treatment on stomatal conductance (gsw), transpiration (E), electron transport rate (ETR), and quantum efficiency in light (PhiPS2).

Using δ13C and hydroscapes as a tool for discriminating cultivar specific drought response

Measurement of carbon isotope discrimination in berry juice sugars at maturity (δ13C) provides an integrated assessment of water use efficiency (WUE) during the period of berry ripening, and when collected over multiple seasons can be used as an indication of drought stress response. Berry juice δ13C measurements were carried out on 48 different varieties planted in a common garden experiment in Bordeaux, France from 2014 through 2021 and were paired with midday and predawn leaf water potential measurements on the same vines in a subset of six varieties. The aim was to discriminate a large panel of varieties based on their stomatal behaviour and potentially identify hydraulic traits characterizing drought tolerance by comparing δ13C and hydroscapes (the visualisation of plant stomatal behaviour as a response to predawn water potential). Cluster analysis found that δ13C values are likely affected by the differing phenology of each variety, resulting in berry ripening of different varieties taking place under different stress conditions within the same year. We accounted for these phenological differences and found that cluster analysis based on specific δ13C metrics created a classification of varieties that corresponds well to our current empirical understanding of their relative drought tolerances. In addition, we analysed the water potential regulation of the subset of six varieties (using the hydroscape approach) and found that it was well correlated with some δ13C metrics. Surprisingly, a variety’s water potential regulation (specifically its minimum critical leaf water potential under water deficit) was strongly correlated to δ13C values under well-watered conditions, suggesting that base WUE may have a stronger impact on drought tolerance than WUE under water deficit. These results give strong insights on the innate WUE of a very large panel of varieties and suggest that studies of drought tolerance should include traits expressed under non-limiting conditions.