I find this an interesting subject. Mainly because two professionals I really respect do native fermentation’s. One is in Napa and the other, Two, is on the next creek over from me.
I always thought what salcoco said was the case, and it just makes sense. However, one, in Napa has had testing done and while “commercial” strains appear, there are many others, some not even Saccharomyces. He only does native.
Two blends portions of native fermentations with inoculated for their final wines.
Both cite more complexity as the reason. That is consistent with the practice of co-innoculating or sequential inoculation with various yeast strains, some non-Saccharomyces as well. There are also some combined yeast mixtures hitting the market these days.
A third, Washington winemaker, lets his crushed fruit, red, sit uninnoculated for a week or more before pitching. It is cool, but not cold where he does this so not a true cold soak. Something starts fermentation as there are bubbles. A native yeast or just last year’s bugs?
An interesting note is I read a study of grapes in the vineyard and in the winery and they found the yeast from the vineyard rarely survived the trip to the winery, I think it was like a day in the study.
I do recognize risks-what if your native species stinks, figuratively or literally? After all, commercial strains have been isolated for a reason. Stuck fermentation is of course a risk depending on alcohol level. So I’ve been chicken and inoculated.
I may try it next year on part of a crop. I keep trying to sort out the process. I don’t think I should use the same punchdowns tool, but is it a fair trial to have two ferment-one native one inoculated, in the same room?
Yes, it is cold and dark outside and I’m disciplining myself to not fiddle, so instead I ponder.