The chemical composition of disease resistant hybrid grape cultivars and its impact on wine quality: an exploratory enquiry into sustainable wines

From the beginning of the yeast autolysis process, several interesting intracellular and cell wall constituyents are released to the media providing different characteristics to the wine, being this process extensively studied in sparkling wines due to their important contribution to their properties (1-2). Yeast derived products (YDs) try to emulate the natural yeast autolysis compounds release enhancing the organoleptic characteristics of resulting wines (2-3). This study is a comprehensive evaluation of the impact of the addition of different YDs added to base wine on the chemical, physical and sensory characteristics of the resulting sparkling wines. METHODS: Chardonnay base wine was employed to carry out this study. Three experimental YDs were added at 5 and 10 g/hL to the tirage liqueur: a yeast autolysate (YA), a yeast protein extract (PE) and an inactivated dry yeast from Torulaspora delbrueckii, (TD), and two commercial specific inactivated dry yeast: OPTIMUM WHITE® (OW) and PURE-LONGEVITY®(PL). After second fermentation, measurements were carried out after 3, 6, 9 and 18 months of aging on lees. General enological parameters, proteins, polysaccharides (HPLC-DAD-RID), volatile compounds profile (GC-MS), foaming characteristics (Mosalux), and descriptive sensory analyses were carried out.

Characteristics related to the climate and the soil of Montefalco in the centre of Italy have been defined in order to evaluate their influence on the red cv.

Wine aging with oak chips is nowadays a common alternative to barrel aging, aiming to improve wine quality through the fast extraction of wood derived compounds. From the pool of wood phenols, ellagitannins have been reported to have the most significant impact on the wine’s organoleptic profile. Their final concentration in wines is influenced by several factors, with toasting level considered as one of the most important.

In Franconia, the northern part of Bavaria in Germany, climate change, visible in earlier bud break, advanced flowering and earlier grape maturity, leads to a decrease of traditionally cultivated early ripening aromatic white wine varieties as Mueller-Thurgau (30 % of the wine growing area) and Bacchus (12 %). With the predicted rise of temperature in all European wine regions the conditions for white wine grape varieties will decline and the grapes themselves will lose a part of their aromatic and fruity expression. Variety change towards the cultivation of later ripening white wine varieties is a very expensive and long-term process, and must be accompanied by special marketing efforts.

Heatwave events, defined as 2 or more days reaching ≥ 38 °C, are an increasingly frequent phenomenon threatening grape production worldwide. Heat stress has been shown to have negative consequences on grapevine physiology, leading to increased evaporative demand and intensified water stress. Due to heatwaves overlapping with important stages of grapevine reproductive development, spanning from berry set to the ripening stage, severe heat can potentially compromise yield and grape quality. The physiological response of grapevine to heat stress suggests a potential use of irrigation to mitigate heatwaves, however there is limited information regarding the irrigation amounts and timings needed for this purpose. Following up on a pivotal trial conducted between 2019 and 2022, in this study irrigation treatments with varying intensity and timing of application were refined to determine their potential mitigation of heat-associated damage to yield and fruit composition.