Sustainable fertilisation of the vineyard in Galicia (Spain)

SO2 play a major role in wine stability and evolution during its aging and storage. Winemaking without SO2 is a big challenge for the winemakers since the lack of SO2 affects directly the wine chemical evolution such as the aromas compounds as well as the phenolic compounds. During the red wine aging, phenolic compounds such as anthocyanin, responsible of the red wine colour, and tannins, responsible of the mouthfeel organoleptic properties of wine, evolved quickly from the winemaking process to aging [1]. A lot of new interaction and molecules occurred lead by oxygen[2] thus the lack of SO2 will induce wine properties changes. Nowadays, the phenolic composition of the wine without added SO2 have not been clearly reported.

Nutrient availability – nitrogen, lipids, vitamins or oxygen – has a major impact on the kinetics of winemaking fermentations. Nitrogen is usually the growth-limiting nutrient and its availability determines the fermentation rate, and therefore the fermentation duration. In some cases, in particular in Champagne, grape musts have high nitrogen concentrations and are sometimes clarified with turbidity below 50 NTU. In these conditions, lipid deficiencies may occur and longer fermentations can be observed. To better understand this situation, a study was realized using a synthetic medium simulating the composition of a Champagne must : 180 g/L of sugar, 360 mg/L of assimilable nitrogen and a lipid content ranging from 1 to 8 mg/L of phytosterols (mainly β-sitosterol).

The wine sector generates a considerable amount of wealth but is facing a growing problem of fraud. Wine counterfeiting is one of the oldest and most common cases of food fraud worldwide. Therefore, the authenticity and traceability of wine are major concerns for both the industry and consumers. To address these issues, robust and reliable analysis and control methods are necessary. Several methods have been developed, ranging from simple organoleptic tests to more advanced methodologies such as isotopic techniques or residual radioactivity measurements.

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.