I have a half gallon of raw cider that was supposed to be for drinking, it sat around too long in the fridge and the jug became firm. I opened it to relieve pressure and take a whiff..... Vinegar! I love cider vinegar for bbq sauce, how can I foster this along? I'm confused because I thought acetobacter turns alcohol into vinegar, but this didn't have any alcohol in it. I can assume fermentation would have kicked off naturally, then the vinegar-part would have started, but there was no sign of fermentation to begin with, the pressure only just now started to build... vinegar.
Do any of you make vinegar? What should I do to make it good vinegar?