Oenological potential of indigenous greek grape varieties and their clones

Several winemaking operations, such as filtration, pumping, and racking, are known to potentially facilitate the incorporation of atmospheric O2 into the wine. Control of grape must oxidation is one key aspect in the management of white wine aroma expression, color stability and shelf-life extension. On the one hand, controlled must oxidation may help to remove highly reactive phenolic compounds, which otherwise could contribute to premature oxidation. And on the other hand, in certain cases of extreme protection of the must from O2 (e.g. pressing under inert atmosphere), it can help to preserve varietal aromas and natural must antioxidants.

Brettanomyces is a world-renowned yeast that negatively impacts the chemical composition of wines through the production of metabolites that negatively impact the sensory properties of the final product. Its resilience in wine conditions and ability to produce off-flavors make it a challenge for winemakers. Currently, the primary control technique involves adding sulfur dioxide (SO2); however, some Brettanomyces strains are developing resistance to this preservative agent. [1] Therefore, new management strategies are necessary to control this spoilage yeast.

Prior to winemaking, organic or mineral nitrogen compound concentrations are usually measured in the vineyard and in grape musts. These indicators facilitate vine cultivation decisions, usually through yield or vigor. During vinification, yeast and bacteria metabolize nitrogen compounds in the musts in order to generate biomass. After fermentation, the microorganisms rerelease a part of this nitrogen as soluble compounds into the wines. Another part remains bound in the lees and can be lost during racking. The must’s natural nitrogen quantities, additional supplements during fermentation, and lees contact management enhance the release of nitrogen compounds to the wines. During ageing these nitrogen compounds – primarily the amino acids – are implicated in the generation of odorous compounds such as heterocycles(1).

Carbon dioxide (CO2) is the gaseous species responsible for the sparkle in all sparkling wines, influencing their
visual appearance, aromas and mouthfeel.

Powdery mildew, caused by fungal pathogens, poses a significant threat to grapevines in the DOCa Rioja region. In efforts to improve control strategies while reducing reliance on conventional phytosanitary products, ozone could constitute a potential alternative. However, it has short persistence, thus requiring frequent treatments. This study aimed to assess the suitability of ozone as an active substance for controlling powdery mildew within a phytosanitary strategy aimed at reducing conventional phytosanitary product usage. The strategy integrating ozone with conventional products yielded powdery mildew levels comparable to conventional treatments in both disease incidence and severity.