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