Well, I'm shaky on the microbiology, but the way this is discussed in the forums, 90 % of wineries buy cultured yeasts to ferment their must, which is "safe" and fast. A lot of biotechnology goes into those, as stems who produce particular aromas in the wine can be selected.
Much less is known about natural yeasts and spontaneous fermentation, which makes for richer, more complex, wines, but is seen as too "risky" within mainstream winemaking training. It doesn't seem to be known, for example, if those yeasts come predominantly from the vineyard or from the cellars, how and when they "take over" when cultured yeasts are stopped being used, and so on. This is mainly because the technical realities of winemaking are commonly veiled by marketing terms like "natural", "wild" or "terroir".
An interestingly honest and well-informed blog about these things by an austrian winemaker is
In reply to Looks a beautiful place. It by Caroline
Yeasts
Well, I'm shaky on the microbiology, but the way this is discussed in the forums, 90 % of wineries buy cultured yeasts to ferment their must, which is "safe" and fast. A lot of biotechnology goes into those, as stems who produce particular aromas in the wine can be selected.
Much less is known about natural yeasts and spontaneous fermentation, which makes for richer, more complex, wines, but is seen as too "risky" within mainstream winemaking training. It doesn't seem to be known, for example, if those yeasts come predominantly from the vineyard or from the cellars, how and when they "take over" when cultured yeasts are stopped being used, and so on. This is mainly because the technical realities of winemaking are commonly veiled by marketing terms like "natural", "wild" or "terroir".
An interestingly honest and well-informed blog about these things by an austrian winemaker is
http://www.bernhard-fiedler.at/weblog/
(Alas, german language only)