Hi, i have made my own vinegar. Last day i forgot to stirr it and white stuff formed on too, which i have cleaned and pour clean vinegar in bottles, yet the withe stuff formed again on top. I cleaned it again from bottle, but again it forms. Its not mother. I think if i put a bit of regular apple cider inside it helps, but i am not sure since i tried that just yesterday. Amy idea, is this mold, is it still healthy to use? If i shake it, some parts of it will fall to the bottom. Its white, or gray, almost like spider web, reminds me of that white thing that forms on milk.