Fermentation Temperature as a Strategy to Limit Hanseniaspora uvarum Proliferation During Spontaneous Wine Fermentation

Hanseniaspora uvarum is consistently observed as the dominant non-Saccharomyces species in grape juice leading to spontaneous fermentations and is often considered a detrimental factor due to the increased volatile acidity associated with its abundance. This study investigated how fermentation temperature affects the competitive interaction between H. uvarum and Saccharomyces cerevisiae, and how these shifts influence microbial community structure during spontaneous grape juice fermentations. Defined single- and co-inoculated fermentations were conducted across a range of temperatures (17, 23, and 25 °C), and cell abundance was quantified by flow cytometry. In parallel, spontaneous fermentations were monitored using ITS metabarcoding to assess temperature-driven changes in fungal community composition. At 17 °C, H. uvarum dominated early fermentation due to its faster growth rate, resulting in slower sugar consumption and prolonged fermentations. Increasing fermentation temperature enhanced the early growth of S. cerevisiae. Consistent patterns were observed in spontaneous fermentations, where higher temperatures increased the relative abundance of S. cerevisiae and shortened fermentation time. These results demonstrate that fermentation temperature is a major driver of yeast competition and suggest that moderate increases in fermentation temperature may help limit excessive H. uvarum proliferation during spontaneous fermentations.