Influence of Fermentation Temperature and Metschnikowia pulcherrima/Saccharomyces cerevisiae Multi-Starter Cultures on the Volatile Compounds of Lugana Wine

Abstract

Low fermentation temperatures are a crucial aspect of winemaking, influencing yeast metabolism, process efficiency, and aroma retention. However, it is a significant source of energy consumption. Here, we investigated the effect of high (20 °C ± 1 °C) and low (16 °C ± 1 °C) temperatures combined with multi-starter fermentations with Metschnikowia pulcherrima (Level2 Flavia and Level2 Initia) and Saccharomyces cerevisiae (EC 1118 and Zymaflore X5) strains on the aromatic profile of Lugana wine. Sequential inoculation at 20 °C shortened fermentation by five days compared to 16 °C, lowering energy consumption for cooling. Significant differences in key aromatic compound classes were observed between the two temperature trials. Wines fermented at 20 °C exhibited more intense tropical and fruity aromas, with 3-MH and 3-MHA concentrations up to ten times higher than those at 16 °C. Such an increase was particularly evident in the sequential fermentation, especially Level2 Flavia/Zymaflore X5, compared to S. cerevisiae alone. In contrast, lower temperatures favored the production of ethyl esters and ethyl acetate, with increases of 14% for ethyl octanoate and 24% for ethyl butanoate. Sensory analysis confirmed these aromatic differences, with all trials at 20 °C enhancing white wine aroma complexity, particularly those involving multi-starter fermentations. These findings provide practical insights for the wine industry, validating sequential fermentation at moderately elevated temperatures as a strategy to improve wine quality while supporting energy-efficient and sustainable practices.