Influence of harvest date on multi-targeted metabolomic profile and sensory attributes of Ribolla Gialla base and sparkling wines

In addition to a balanced production level, the timing of grape harvest is a crucial factor to be considered for the winemaking process of sparkling wines. A sufficient accumulation of sugars and an optimal level of acidity in grapes throughout ripening is necessary not only to achieve the desired alcohol levels in the wine but also to guarantee the biosynthesis of the aromatic precursors. To target optimal grape ripeness and maximise the positive sensory attributes of the wine produced, the work presented herein deals with a study on whether an extended harvest date might have a greater positive organoleptic impact and lead to an increase in important odour–impact compounds. In the resulting Ribolla Gialla monovarietal sparkling wines, a one-week delay after reaching technological maturity of the grapes expressed an improvement in the aromatic profile in the obtained samples by altering the profile and abundance of grape-derived compounds and fermentative esters. This was consequently reflected in the sensory evaluation, as the wines achieved higher scores for ‘floral’, ‘citrus fruit’, and ‘yeast’ sensory descriptors when the grapes were harvested a week after the minimum compromise between total acidity concentration and total soluble solids. Moreover, an extension of the harvest date is not necessarily correlated with the formation of untypical ageing off-flavour substances that could be detrimental to the quality of sparkling wines. Conversely, the lipid content proved to be more dependent on the climatic factors of the individual vintage compared to subsequent harvest time. By merging a multi-targeted approach of exploring wine metabolites and sensory characteristics, it is thus possible to predict an optimal harvest date for obtaining high-quality Ribolla Gialla sparkling wines.