Managing the conditions of the pied de cuve offers wine with different organoleptic profiles

Abstract

Saccharomyces cerevisiae is responsible for alcoholic fermentation (AF) and is widely distributed as active dry yeast (ADY). While optimal ADY rehydration conditions are well established, the management of yeast biomass propagation (“pied de cuve”) remains poorly documented with respect to its impact on fermentation performance and wine quality. This study evaluated the influence of propagation medium and growth duration on AF kinetics and on the chemical and sensory profiles of wines. Yeast biomass was propagated either in YEPD or in a low-cost beet molasses-based medium (50 g/L beet molasses supplemented with 1 % yeast extract), for 24 or 96 h. Fermentations were conducted in Chasselas must using the four resulting inocula (Y_24h, Y_96h, M_24h, M_96h), with directly rehydrated ADY used as a control. Yeast viability and vitality were assessed on days 3 and 14 of AF, and final wine composition was analyzed by HPLC and GC. Sensory differences were evaluated using Napping and Newman–Keuls tests. All propagation conditions resulted in high yeast viability (> 99 %). The M_24h inoculum exhibited a slightly higher maximum specific growth rate (μmax). While cell viability remained similar among treatments on days 3 and 14 of AF, yeast vitality differed at the beginning of fermentation, with higher vitality observed for inocula propagated for 24 h. While viability remained similar throughout AF, yeast vitality differed at the beginning of fermentation, with higher vitality observed for inocula propagated for 24 h. No significant differences were detected in the chemical composition of the wines. However, distinct aromatic profiles were perceived in both mouth and nose. Although the sensory analysis was exploratory, the consistent discrimination observed across replicates suggests that yeast propagation conditions induced robust and perceivable sensory differences. These results indicate that yeast propagation can be used as a practical and economical tool to modulate wine sensory profiles without negatively affecting fermentation kinetics or chemical composition.

References

Mas, A.; Portillo, M. C. (2022). Strategies for microbiological control of the alcoholic fermentation in wines by exploiting the microbial terroir complexity: A mini-review. Int. J. Food Microbiol., 367, 109592