The wine microbial consortium: a real terroir characteristic

Yeast, bacteria, species and strains play a key role in the winemaking process by producing metabolites, which determine wine sensorial qualities. Therefore microbial population enumeration, species identification and strain discrimination from berry surface at harvest to storage in bottle are fundamental. The microbial diversity and significance of its variation according to the estate localization have not really been thoroughly considered in literature. This is the focus of this work. That should be of great interest because the spontaneous microbial population dynamics associated with a wine producing estate provide information on what might be considered as the method to obtain specific terroir typed wine. The both use of conventional microbiological methods like microbial population enumeration on nutritive selective media and efficient molecular tools of species identification like PCR-RFLP for yeasts and PCR-DGGE for bacteria and strains discrimination have demonstrated significant microbial differences between different estates localized in the Bordeaux area. Theses results appeared very interesting since certain microbial species are clearly specific of certain estates, in particular the bacterium Pediococcus parvulus, and also some strains of Saccharomyces cerevisiae, of Oenococcus oeni and Brettanomyces bruxellensis. Within an estate this specificity persists from one year to another. These differences observed suggest that the indigenous winemaking processes can contribute to the specificity of the wines produced on the various estates.. That concludes to the hypothesis of a microbial part in wines speficities.