On 2 Mar, 18:53, Joe Sallustio > wrote:
> On Mar 1, 5:25 am, michael > wrote:
>
> > I have some particularly promising white wine(Schonburger)which tastes
> > beautiful now.The grapes were harvested in October 2007,racked in
> > November and 30ppm sulphite added.It is now clear * in a 1 gallon
> > glass demijohn and I wish to make sure that it lasts into the
> > summer.Will adding some more sulphite (another 30ppm) protect it,and
> > should I put it somewher cool to keep it in best condition.I live in
> > England (we do make good wine here!)and the summer temperatures rarely
> > exceed 80F.Should I also keep it out of the light.I know that this is
> > a small quantity,but I do wish to develop good practise.
> > Michael
>
> Michael,
> Since you only want it to last another half a year you have some
> flexibility. *The effectiveness of sulfite is dependent on the amount
> of acid in the wine, if you don't have access to a calibrated pH meter
> it's hard to say whether you need any more or not. *The real key is
> keeping oxygen away from your wine. *30 ppm is more than enough if the
> pH is 3.2, not enough if the pH is 3.4. *A local schools science lab
> may be willing to test it for you.
>
> If the wine is dry and a bit tart, you may be fine. *Bottling it and
> keeping it cool will help protect it. *If the pH is low and you end up
> with 60 ppm SO2 in it you may taste it so measurement of *both the
> sulfite level and more importantly the pH would be preferable.
>
> Joe

Thanks,Joe.I tend to measure the pH of my wines using pH strips,which
tend to be only accurate to +-0.2 or so,but they are a good guide.As
you know from our previous exchanges,I have in the past not used
sulphite at all and have lost a few gallons,including this variety
Schonburger.I did not put any sulphite in during the initial press
this year,but probably about 50ppm on first racking.So I will measure
the pH and add a little more now as you are suggesting.In the future
if I wish to keep the wine even longer,say a couple of years or so,do
I have to add more sulphite than you are suggesting-would it be better
then to add much more sulphite now or add it in smaller doses every 6
months.I suppose commercial winemakers have to add a lot of sulphite
on bottling as they do not know the date of consumption.

The other point you raise is that it would help to bottle the wine
(and keep it cool) to make it safe.I do not really understand why wine
bottled is safer than wine in a glass 1 gallon container,unless it is
the problem with inadequate closure.At the moment,the glass container
has a glass airlock (incidentally,we cannot obtain glass airlocks in
England anymore-only plastic which of course are porous to air.Is it
possible to obtain them still in the U.S.?) and I am leaving it like
that for a couple more months in case of some more fermentation;then I
will tightly bung the glass container with sufficient headroom to
allow for expansion as the weather warms up,using a rubber bung.With
bottles is it just that a cork or modern plastic enclosure is a much
more secure bung-rubber bungs can be forced out occasionally?