On Mon, 5 Jan 2009 16:34:39 -0800 (PST), Madalch >
wrote:

>On Jan 5, 4:21*pm, wrote:
>> Natural yeast will quit around 11% alcohol. If your grapes were very
>> ripe the fermentation will stick with residual sugar left.
>
>If he's lucky. His two carboys wound up with different yeast
>colonies, since one of them fermented a lot more than the other.

Some wild yeasts do well to get as high as 4%.

You can skip the sulfite if you wish to take a chance with that,
especially after the initial 24 hours (more chancy before that time),
but adding a cultured yeast for winemaking (not for bread or beer
making) is not using a chemical additive. It's a natural product.

Leaving things up to chance gives you unpredictable results, as you've
seen different results even between the two batches.

Covering the fermenters and using an airlock will prevent the
unpredictable yeasts and bacteria from getting into your wine.