Differences in wine quality between vineyards have long been attributed to processing techniques and seasonal variation. But research now suggests that regional differences between wines are shaped by microbes — specifically, fungi and bacteria. Cultivating certain grape microbes may actually improve wine flavor. ...
For example, Napa Chardonnay musts were loaded with the bacterial group Firmicutes and the fungal group Eurotiomycetes. By comparison, Sonomy [sic] Chardonnay musts contained high concentrations of the fungus Botryotinia fuckeliana and Proteobacteria. They found that the grape variety also strongly influences the microbial patterns across regions and vintages.
What's more, the team discovered that local environmental conditions — wind, temperature and relative humidity, in particular — are responsible for driving the biogeographical diversity in microbial communities. Vintage also affects grape must microbiota, and this fits in with the influence of climate, given the change in climate between years.
"What we are really seeing here is that region, environmental conditions and grape varieties shape the microbial communities of the grapes that make it into the fermentation process and shape wine quality," Bokulich said.