What are the primary metabolic pathways of non-Saccharomyces yeasts during wine fermentation, and how do they influence the final wine's sensory profile?

Non-Saccharomyces yeasts, present naturally on grape skins and in wineries, play a role in the early stages of wine fermentation before Saccharomyces cerevisiae becomes dominant. These yeasts have distinct metabolic pathways that significantly influence the final wine's sensory profile. One key pathway is the production of glycerol. Many non-Saccharomyces yeasts, such as Metschnikowia and Candida species, produce higher levels of glycerol than S. cerevisiae. Glycerol contributes to the wine's mouthfeel, adding a perception of sweetness and viscosity. Another important metabolic pathway is the production of volatile aroma compounds. Non....