Most commonly , winemakers will crush grapes as soon after picking as
possible and will
add metabisulphite to inhibit wild yeasts and ohter organisms( though not
all will use metabisulfite as some really are against chemicals in their
wine). After the meta has had a chance to do it's thing, cultured yeast is
added to out - muscle the competition. In your
case I would add some wine yeast to it if u think there is any chance it
will turn out o.k.
A book on winemaking can be very informative or you could look at this
Good Luck, Chad
> HI & thanks for the repsonse to my post about mold on grapes. Guess I
> should pay attention to grape advice from anybody called Giovanni : )
> Sadly I think the grapes have pre-empted all your suggestions as
> there's now a spontaneous ferment underway. I think I'll just let it
> go and see what I have once it's finished. They are concord grapes so
> it's not as if I might lose some "premium" juice. If it doesn't taste
> noxious near the end I can add sugar syrup, or more grape juice, and
> carry on.
> I"ve only ever made "country" wines before; sometimes using grapes but
> always in low quantity, with lots of sugar to raise the SG, so I don't
> understand, if molds are undesirable, how do "real" winemakers (i.e.
> using just grapes) avoid them without sterilising the fruit and
> thereby killing off the natural yeasts? How do they avoid what I've
> ended up with?
> I don't suppose I'm going to poison myself - what d'you think? (I
> won't hold you responsible if you're wrong - come back & haunt you or
> Alexander Miller, Port Alberni B.C. Canada
> >Harvested abt 1/4 of my grapes....
> > Now they show a white mold growing.....
> >still use them for wine, how can I be sure?
> And got the reply:
> >>.....Next time, sulfite and
> >>store at low temperature (the lower the better).
> >>Depending on quantity, you may be able to wash off most of the
> >>mold (immersing in water and lightly shaking, jet-spraying with your
> >>water hose, etc..). Then I suggest sulfiting at 150-200 ppm (it's not
> >>as bad as it sounds!) and let rest tightly covered in cool room (10-14
> >>is OK) for 48 hours.
> >>I also suggest you prepare a yeast starter for a 'fast start'.
> >>No guarantees. But the odds are pretty good! Chances are you will not
> >>have any problems whatsoever. What have you got to lose? Someone else
> >>may advise to get rid of them. I suggest you go ahead.
> >>Best of luck, Giovanni.