This is my first year of wine making. I moved into a house that had a very small vine garden (trellis). I've managed to produce 3 gallons from my grapes, but the third gallon harvested at the end of the season has some sort of film forming on top of the liquid. Is that affecting the liquid? Should I just dispose of it or siphon it to a clean jar and just all will be fine? I didn't have this issue with the 2 previous gallons.