New article on ethanol reduction by multistarter yeast inoculum

Effect of a multistarter yeast inoculum on ethanol reduction and population dynamics in wine fermentation

Xiaolin Zhu, Maria-Jesús Torija, Albert Mas, Gemma Beltran*, Yurena Navarro

Foods 2021, 10, 623. https://doi.org/10.3390/foods10030623

Microbiological strategies are currently being considered as methods for reducing the ethanol content of wine. In this study, fermentations started with a multistarter of three non-Saccharomyces yeasts (Metschnikowia pulcherrima (Mp), Torulaspora delbrueckii (Td) and Zygosaccharomyces bailii (Zb)) at different inoculum concentrations, and S. cerevisiae (Sc) was inoculated into fermentations at 0 h (coinoculation), 48 h or 72 h (sequential fermentations).

The analysis of the microbial populations showed Td as the dominant non-Saccharomyces yeast in all fermentations, and Mp the minority yeast. Sc was able to grow in all fermentations where it was involved, being the dominant yeast at the end of fermentation. 

We obtained a significant ethanol reduction of 0.48 to 0.77 % (v/v) in sequential fermentations, with increased concentrations of lactic and acetic acids. The highest reduction was achieved when the inoculum concentration of non-Saccharomyces was ten times higher (10⁷ cells/mL) than that of S. cerevisiae.