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

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 degrees C +/- 1 degrees C) and low (16 degrees C +/- 1 degrees 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 degrees C shortened fermentation by five days compared to 16 degrees C, lowering energy consumption for cooling. Significant differences in key aromatic compound classes were observed between the two temperature trials. Wines fermented at 20 degrees C exhibited more intense tropical and fruity aromas, with 3-MH and 3-MHA concentrations up to ten times higher than those at 16 degrees 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 degrees 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.