Why add yeast?

[dinnerstick]

Hello all, I am curious as to why so few people on this forum (seemingly) ferment with the natural yeasts present on the apples. When I have nice fresh apples from home or orchard I tend to let nature take its own course on the cider, and I have never had a batch go wrong (although i have very few batches under my belt) knock on wood. Whereas if i use polished supermarket fruit i do add yeast. In one current side-by-side experiment I am fermenting a small batch naturally and one with champagne yeast. The champagne stuff was off to the races of course whereas the natural stuff was really slow getting going, and tasting them while racking there is quite a difference, the champagne is super-yeasty and almost pineappley whereas the natural stuff is sort of sweet and sour (a lot more sugar still to ferment) without the bready odors of the other. So back to my point, aside from that you have some greater control over the finished product, why kill and add yeast, when the natural stuff does such a great job??
All viewpoints welcome please!

 

[Nikkimaija]

I have done both and enjoyed both. The natural fermentation turned a little moldy on top and I was sure it was ruined, but I just racked out from underneath the mold and it seemed to taste okay. I followed this up by blending the already fermented dry cider (mine went fast, just a week or so) with a batch of wit and pitching a nice Belgian yeast, so it was sort of a combo batch. So far so good though the flavors are still melding a bit I think.

 

[mikefox]

To quote from Jack Keller's website:"Wild yeasts are to wine what weeds are to a garden."

"Yeast make the wine and therefore are essential to the process. If you use fresh ingredients, such as fruit, berries or herbs, yeast will come into your wine from outside naturally. They also float in the air in almost every kitchen, so that a fruit juice left uncovered for an hour on the kitchen counter will collect a culture. Neither of these yeasts should be used in making wine, nor should baking (bread) yeast. The yeast on fruits and berries are wild, and probably contain strains of yeast unsuitable for wines. Some produce off-flavors and odors, while others only produce small amounts of alcohol. Yeasts found in the kitchen air are generally bread yeasts and also do not make enough alcohol for most table wines. More importantly, molds also float around in the kitchen and will ruin an otherwise perfect must. Inhibit these yeasts with sulfites and inoculate your must with cultured wine yeast strains. Hydrate the active dry yeast (ADY) cultures in a starter solution and allow them time to begin reproducing themselves."

And thats why wild or bread yeast should stay out of the must.
And also you should pasteurise the must before fermenting thus killing wild yeast and most importantly deadly bacteria like E.coli

 

[dinnerstick]

mikefox: although i agree with all of that in principle, the fact is that when i ferment with the natural yeast the end result is always good! and i have had a few commercially produced wines fermented in the same way (albeit in a far more controlled environment than my carboy) and many british and french cider houses also go natural, so it seems the exception rather than the rule that you will get nasty yeasts as the predominant strain, and i have (so far!) never had mold, and have certainly never had an ethanol shortage... plus i find the idea of pressing local apples and leaving it to the wild yeast a romantic one, true 1-ingredient cider