My wine is undergoing maloactic fermentation in carboys. A white-ish light film or sediment is developing on the carboy neck above the wine, but no film or sediment appears to be floating on the wine. After weekly stirring of lees, i am spraying a mist of everclear on wine to discourage acetobactor, which washes away the film on the glass - but it still comes back within a week. Cannot smell any rotten egg smell, though wine smells a bit musty - but not too much, so smell may be normal. Should i be worried? and if so, what to do??
(Added 40ppm sulphite before primary fermenation but nothing else yet. The film in neck also showed up last year during MLF, but not in years before. Last year was first year i did a cold soak prior to primary fermentation - did cold soak again this year.
Thanks in advance for any help!