Résumé
This thesis is presented as part of the Diplôme National d'OEnologue for Maison M.CHAPOUTIER for the 2021 vintage. The concern for fair and resonant use as well as thedesire for a global reduction of all oenological inputs pushes wineries to question themselves.The choice focused on a preventive and non-curative action that seems to respond to thephilosophy of the vineyard. To achieve this, an experiment to see the potential influence ofthe pre-fermenting phase on the populations of Brettanomyces was set up. To do this, thestudy was carried out by comparing a modality in native yeasts and a second modality seededwith the help of a previously prepared vat base. Each modality being composed of two tanks.An analytical follow-up was then carried out to follow the evolution of the population ofBrettanomyces alive, dead and VNC, throughout the life of the wine. Finally, the results donot seem convincing, but the prospects are numerous, including the study of a vintage effectand the intrinsic influence of the winery.