Advances in the chemistry of rosé winemaking and ageing

Water is one of the most limiting factors for viticulture in Mediterranean regions. Former researches showed that water shortage hampers both vegetative and reproductive developments. INRA is running programs to breed varieties carrying QTL of tolerance to major fungi, i.e. powdery and downy mildews. Some varieties have been already certified or are close to be certified. However, little is known about the response of these varieties to water deficit, which behavior is critical for their development. This study characterized physiological responses of 4 new varieties to water deficit and described relationship between them.

Merlot grapevine is the second wine cultivar most planted in the world and especially in the Bordeaux wine region. This cultivar has many advantages in producing high quality wine; however, in the last decade, climate change has increased the sugar concentration in berries at harvest and shortened the maturation cycle. If this has been up to now a great opportunity to improve wine quality profile, we are touching the tipping point. High sugar concentration at harvest induces high alcool content in wine which can negatively impact wine quality. There are many viticultural and oenological practices possible to limit this effect. In this study we focus on plant material through intra-varietal diversity of Merlot cultivar.

The ripening of grapevine berries encompasses complex morphological and physiological processes, especially at veraison. Berry shrivel (BS) is a ripening physiological disorder affecting grape berries with visible symptoms appearing short after veraison. The main symptoms of BS are a strong reduction in sugar accumulation, inhibited anthocyanin biosynthesis and high pH values. The most popular red grape cultivar in Austria “Blauer Zweigelt” (Vitis vinifera L.) is specifically prone to develop the BS ripening disorder and up to date a no specific cause or causes could be identified. Recently omics approaches have identified and characterized key processes during grapevine ripening. Among them a small subset of genes, called SWITCH, have been described as markers for the onset of the ripening process in fruits.

The global wine production is continuously evolving to meet the new demands and preferences of consumers. in this evolving scenario, it’s important to determine which trends will be short-lived and which will remain over time. The promotion of healthier habits has encouraged consumers to try to find alternatives with low or no alcohol content. The challenge for the industry is to produce an alcohol-free wine that retains the familiar aromas and mouthfeel of traditional wine but without alcohol. Ethanol is the most abundant compound in wine, excluding water.

Oxygen management is crucial in terms of wine quality. Even more for white and rosé wines, which are less protected against oxidation than reds due to the lower levels of antioxidant polyphenols. This need is due to the existence of equilibria between chemical forms depending on the redox potential.