Thanks Frederick & Ben for your helpful comments.

Ben, You're right the temperature of my fermentation is quite cool and
my Gewurz, Riesling and Pinot Grigio are nearly finished fermenting, now
down in the 1.000 range. I just added SO2 to bring the level up to 0.8
ppm molecular as based on the pH of each, ranging from 3.33 down to 3.22.

Thanks again to both of you.

Glen Duff
----------------------------

wrote:

> Glen,
>
> You should sulphite as soon as the fermentation ends (which would be <
> SG 1.000). Sulphiting during fermentation is pointless (and potentially
> harmful) since all the SO2 added will simply bind to acetaldehyde. I
> recommend you also give the must a decent dose of SO2. Of course, there
> will be a small window of opportunity for MLB during fermentation (when
> SO2 levels are very low due to binding & "blow-off") and you can try
> and control them with a low temperature (wouldn't you be doing a cool
> ferment with Gewurz and Riesling anyway?).
>
> HTH,
> Ben
>
> Improved Winemaking
> http://members.tripod.com/~BRotter/MLF.htm
>
>