The art of making homemade wine is a venerable process but not without occasional tribulations such as surface mold. It is possible to remove and eradicate the mold with a high probability of salvaging the wine. Prevent future mold outbreaks on your wine by keeping fermentation vessels, siphon hoses and other equipment properly sanitized.
Pour the wine into a clean, sanitized bottle. If in doubt, treat the bottle using iodophor sanitizing solution. Pour the wine through filter paper to prevent the mold from being transferred. If you want sediment to remain in the wine, don't use filter paper; instead, pour slowly and carefully to keep it in the original bottle.
Throw away the previous cork, as it is likely contaminated. If using an airlock, empty the water and sanitize it with the iodophor solution. Also treat the old bottle in the iodophor solution before reusing.
Combine 2 crushed campden tablets, 1 tsp. of lemon juice and 1 cup of the wine for every gallon of wine being treated in a separate, sanitary dish.
Add the mixture to the wine. The sulfur dioxide in campden tablets and the acids in the lemon juice work together to kill remaining bacteria and mold in the wine.
Re-cork the bottle and let the wine sit for two days.
Taste the wine to check the flavor. If there are no hints of mold, the wine is ready to drink. If mold is still detectable, discard the wine.