Occurrence and Persistence of Population in Spontaneous Fermentation and the Relation with "Winery Effect".

The yeast ensures successful fermentation in winemaking, although the persistent use of commercial strains lead to the loss of aroma complexity of wines. Hence, the research of indigenous with proper oenological features and well adapted to specific wine-growing areas become of great interest for winemakers. Here, 206 pure cultures of were isolated from two wineries during a two-year sampling campaign and bio-typed through interdelta sequences analyses with the aim to evaluate the occurrence and persistence of the wild population linked to each winery. Both wineries belong to the same Verdicchio DOC wine area (Castelli di Jesi), and never used commercial yeasts during fermentation. Results showed 19 different biotypes with a specific population of in each winery, without cross-contamination with each other and with commercial starter strains. Moreover, inside each winery a persistence of some dominant biotypes was observed over time (three biotypes in winery 1; 95% of isolates in the two years and one biotype in winery 2; 20% of isolates in the two years), indicating a sort of "winery-effect". The evaluation of populations for the oenological characters by microfermentations showed a proper and well distinct aromatic imprinting on the resulted wines supporting the concept of "winery effect".