Secondary fermentation is often problematical is the yeast in the
first fermentation removes nutrients leaving the wine depleted.
Industrially I have seen stuck fermentations due to deficiencies of
nitrogen, zinc, B vitamins, magnesium.
The most common problem is zinc deficiency corrected by 5gms of Zinc
sulphate per four thousand litres not much.
If the product is fermenting properly there is plenty of CO2 being
produced and there is no air on top of fermenter that would allow mold
growth.

Bob M
www.molab.co.nz

On Mar 27, 12:43*pm, JaeRae > wrote:
> I'm new to this group and new to winemaking and I need some help. *I
> began a secondary fermentation on some white wine on Feb. 19th and it
> seems to be getting small spots of mold on top. *Is it ruined and what
> did I do wrong? *I washed everything with B-Brite and added potassium
> metabisulfite prior to the primary fermentation. *I started some red
> wine last fall and it seems to be doing fine.