Grape composition and wine quality of Muscat Hamburg cultivar after a specific inactivated dry yeast application as adaptation strategy to climate change

Abstract

Context and purpose of the study – In a climate change context, the management of Mediterranean vineyards should be adapted to the new environmental conditions. Predictive models underline that in the future the most of the Mediterranean vineyard regions is expected to experience further warming events producing challenges in ripening balanced fruit. It is already registered that in warm and dry summers, the ripening process is faster and the balance between phenolic and technological (sugar) maturity may not be the desirable. This study investigates the use of specific inactivated yeast derivatives sprayed on the entire canopies of field grown cv Muscat Hamburg vines.

Material and methods – The trial was carried out in a vineyard located in Nea Agchialos, Central Greece. Muscat Hamburg vines were tagged and randomly assigned in pairs to a spray treatment with a specific inactivated yeast derivatives (IYT, LalVigne™ MATURE, with the patent pending application technology of Lallemand, 100% natural formulation) or unsprayed (C = control vines). The entire canopy of all IYT vines were sprayed at veraison with IYT solution. The treatment was repeated at the same concentration 10 days later. At harvest, yield parameters, bunch morphology, grape composition and wine analysis were recorded.

Results – There was no effect of inactivated yeast treatment on yield, bunch weight, berry weight and bunch compactness, whereas relative skin mass was increased on IYT vines. At harvest, TSS, TA and pH were similar in both treatments while treated vines showed higher total anthocyanin and phenolics content, improving phenolic maturity of the berries. Finally, wine color quality was improved on IYT vines. Our results indicate that in the Mediterranean vineyard regions, often characterized by dry and hot vintages, specific inactivated yeast derivatives applications can be an easier alternative to other traditional management techniques (e.g. cluster thinning, early defoliation, girdling) for improving phenolic maturity in grapes.