 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

White wine light-strike fault: a comparison between flint and green bottles under the typical supermarket conditions

Consumer preference favors flint-glass wine bottles over the traditional dark-colored, but it is documented that light exposure can cause white wines to produce off-aromas and change in color, and consequently da[1]mage their quality. Aim of the study was to study the white wine shelf life under the typical supermarket conditions, by recording the light and temperature exposure, the colorimetric changes, and the light-strike fault. METHODS: One pilot experiment based on two white wines and eight-time points and one kinetic experiment based on four white wines and seven-time points were designed and realized using a typical supermarket shelf for 32 and 50 days, correspondently. By installing prototype sensors at 32 points of the shelf, the temperature, UV, IR, and Visible light exposure were registered every 10 min. Approximately 600 commercial wines, bottled in flint and colored glass, were used. The colorimetric changes of the wines were registered and the light-strike fault was evaluated.

EFFECT OF FUMARIC ACID ON SPONTANEOUS FERMENTATION IN GRAPE MUST

Malolactic fermentation (MLF)¹, the decarboxylation of L-malic acid into L-lactic acid, is performed by lactic acid bacteria (LAB). MLF has a deacidifying effect that may compromise freshness or microbiological stability in wines² and can be inhibited by fumaric acid [E297] (FA). In wine, can be added at a maximum allowable dose of 0.6 g/L³. Its inhibition with FA is being studied as an alternative strategy to minimize added doses of SO₂⁴. In addition, wine yeasts are capable of metabolizing and storing small amounts of FA and during alcoholic fermentation (AF).

Rootstock selection moderates the effect of rising temperatures through drought tolerance and modulation of stomatal conductance

Climate change is increasing crop evapotranspiration and reducing water availability, especially in the Mediterranean area.

Health benefits of wine industry by-products

The total global production of wine in 2021 was estimated at around 250 million hectoliters. The 30% of the total quantity of vinified grapes corresponds to wine by-products that represent nearly 20 million tons, of which 50% corresponds to the European Union. Wine by-products have been used for different purposes, in agriculture, cosmetics, pharmacy, biorefinery, feed, and the food

Impact of grape ripening and post-harvest withering on must composition and fermentation kinetics

Postharvest dehydration is a widely employed technique in winemaking to enhance sugar concentration and secondary metabolites from grapes. Different grape varieties exhibit varying responses in terms of dehydration rate and the resulting chemical composition.