"Don S" > wrote in message
om...
> > I'm not sure just how to answer your question Don.
> >
> > In general, H2O2 reacts with SO2 and produces sulfuric acid. Excessive
wine
> > oxidation will occur if more H2O2 is added after all the SO2 is gone.
> >
> > So, one answer might be.....measure the free SO2 and add enough H2O2 to
> > oxidize the excess SO2. But, significant amounts of sulfuric acid will
be
> > produced if your wine contains large amounts of SO2, and you may not
like
> > the taste of sulfuric acid.
>
>
> Lum,
> It sounds then like splash racking ispreferable to using H2O2
> then. How does SO2 break down in the presence of oxygen?
> I think one more dose of 1.7 ml/gal and a splash rack then...
> hmmmm, I always end up on that "why toss it" path.
>
> I gotta buy that tester, I gotta buy that tester...
>
> Don

Don,

In wine, free SO2 is in three forms: as a dissolved gas (SO2), as bisulfite
(HSO3-) and as sulfite (SO3--). At wine pH, most of the free SO2 is in the
bisulfite form. Splash racking removes SO2 from the wine several ways. (1)
Some of the dissolved SO2 gas comes out of solution and drifts away in the
air. (2) Oxygen is introduced into the wine, and some of the alcohol is
oxidized into acetaldehyde. Bisulfite then reacts with the acetaldehyde and
becomes bound SO2. (3) Some of the sulfite reacts with oxygen and produces
sulfate (sulfuric acid).

I would try (1) another dose of H2O2 plus lots of splashing. (2) Build a
large starter using Prise de Mousse yeast. (3) Add very small quantities of
wine to the starter (1/4 wine, 3/4 starter) until all of the wine is
fermenting.

The renewed fermentation will blow off more SO2 gas and will
reduce much of the acetaldehyde back into alcohol. But, much of the sulfate
will remain in the wine.

Good luck,
lum
Del Mar, CA, USA