On Jan 5, 5:21*pm, wrote:
> On Jan 5, 4:17*pm, Madalch > wrote:
>
> ...
> Natural yeast will quit around 11% alcohol. If your grapes were very
> ripe the fermentation will stick with residual sugar left.

All of the cultured yeasts that are commonly used are "natural". They
were isolated from the environment in various wine producing regions
of the world. I've heard recently of a genetically modified strain,
but it isn't available in small sachets for home wine makers yet.

Native, wild, or feral yeasts may be anything. If you just crush
grapes and let them start fermenting, the yeast strain at work may be
one that has never been put to the task of wine making, or it may be
one that has a long history and was released into your environment in
recent times. For this reason you could end up with a fermentation
stopping at 8 percent or finishing at 20%.

Relying on native or wild yeasts is like a box of chocolates, "you
never know what you're gonna get".

Greg G.