Cellar Temperature Affects Brettanomyces bruxellensis Population and Volatile Phenols Production in Bordeaux Aging Wines

Brettanomyces bruxellensis is a spoilage yeast particularly dreaded in red wines where it produces volatile phenols, whose sensorial properties lead to wine spoilage. The development of this yeast often occurs during wine aging, especially during the summer. We show that in the Bordeaux region, the temperatures of some cellars rise significantly in July, August, and September. This greatly increases the growth rate of B. bruxellensis strains, in both permissive and more unfavorable wines. Therefore, although the temperature does not affect the specific rate of formation of ethyl phenol, raising the wine temperature from 2 to 6°C makes the appearance of volatile phenols much earlier and faster, regardless of the wine or the yeast strain present. A closer control of the active populations and a closer monitoring of the wines in aging is thus essential in the summer, particularly in cellars where the temperatures is badly regulated.