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Biogeography is the descriptive and explanatory study of spatial patterns and processes involved in the distribution of biodiversity. Without biogeography, it would be difficult to study the diversity of microorganisms because there would be no way to visualize patterns in variation. Saccharomyces cerevisiae, “the wine yeast,” is the most important species involved in alcoholic fermentation, and in vineyard ecosystems, it follows the principle of “everything is everywhere.” Agricultural practices such as farming (organic versus conventional) and floor management systems have selected different populations within this species that are phylogenetically distinct. In fact, recent ecological and geographic studies highlighted that unique strains are associated with particular grape varieties in specific geographical locations. These studies also highlighted that significant diversity and regional character, or ‘terroir,’ have been introduced into the winemaking process via this association. This diversity of wild strains preserves typicity, the high quality, and the unique flavor of wines. Recently, different molecular methods were developed to study population dynamics of S. cerevisiae strains in both vineyards and wineries. In this review, we will provide an update on the current molecular methods used to reveal the geographical distribution of S. cerevisiae wine yeast.

In the last years the use of a multistarter fermentation process has been proposed to improve the organoleptic characteristics of wines. In the present study the fermentation performances and the interactions of mixed and sequential cultures of Hanseniaspora uvarum, Candida zemplinina, and a strain of Saccharomyces cerevisiae isolated from organic musts were investigated. To evaluate the oenological performances of the tested strains microvinifications in pasteurized red grape juice from Montepulciano d’Abruzzo cultivar were compared. The course of fermentation has been controlled through classical determinations (CO2 evolution, ethanol, glycerol, pH, total titratable acidity, sugar content, free sulfur dioxide (SO2), dry extract, sugars, organic acids, and volatile compounds). Moreover, the yeast population was determined by both culture-dependent and independent approaches. In particular, the pure culture of H. uvarum and C. zemplinina did not end the fermentation. On the contrary, when S. cerevisiae was added, fermentations were faster confirming that yeast interactions influence the fermentation kinetics. Moreover, C. zemplinina showed a good interaction with S. cerevisiae by increasing the fermentation kinetic in high gravity Montepulciano must, with low ethyl acetate and acetic acid production. This study confirmed that non-Saccharomyces yeasts play a crucial role also in organic wines and their activity could be modulated through the selection of appropriate strains that correctly interact with S. cerevisiae.

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