I too just had a struggle with mold in wine. It is a red made from
grapes and tastes very good but after my last racking I sulfited 3
gallons of the stuff and in a few days I had this mold on the surface.
It was a very thin white mold.
I don't believe that it was an infection of the wine as much as a
problem with sanitation. I am normally very stringent about sanitation.
Several days after I racked and sulfited the wine the mold appeared. I
took a paper towel and wiped the exposed portions of the carboy and
dabbed it into the wine a little. I then took some solution made from
campden tablets in a spray bottle and sprayed the sides of the carboy
and the bung and changd the airlock. insured the carboy was topped up
correctly (which was never an issue) and put the bung into the bottle.
The thing here is the spray bottle. After all I had just sulfited and
did not reall want to add more to the wine. So the spray bottle was able
to concentrate my efforts to a small area and quite possibly kept me
from seriously over sufiting my wine. You all can get the spray bottles
at any Wal Mart for a buck or two.
By the way its been three weeks and the mold has not returned.