Characterization of the redox potential during the fermentation of model wine solutions by Saccharomyces cerevisiae

In winemaking, the main causes of incomplete fermentation are unfavorable chemical conditions such as inappropriate pH, extreme temperature, or a shortage of nutrients. Alternatively, in spontaneous fermentation, where yeasts with sufficient fermentative capacity in the must can be scarce or absent, it is difficult to detect early signs of stuck or sluggish fermentation. Although the redox potential (ORP) is known to affect yeast metabolism during fermentation, few studies have examined the relationship between ORP behavior and fermentation dynamics across strains of Saccharomyces cerevisiae. In this study, ORP dynamics were investigated in 22 S. cerevisiae strains, including both commercial and wild-type strains. The ORP profiles varied considerably among the yeast strains, with some exhibiting a typical bathtub-shaped pattern and others showing an earlier ORP increase during the late stage or fluctuating trends. Statistical analysis of the ORP characteristics at each stage of fermentation showed significant differences among the groups classified by fermentation time and residual sugar. These results may suggest that changes in ORP during fermentation can reflect fermentation faults such as arrested fermentation.