SpontaneityThis cider is exposed to UV light to kill off bacteria, but that shouldn't kill off the natural local yeast. When I bought the cider I didn't have an empty fermenter - so the cider sat for almost a week. I probably should have put it in the refrigerator, but for some reason I just left it in the living room. Before transferring to the fermenter I could see a little foam inside the jugs, showing that the cider had already started to ferment.