I've read that you can use apple cider vinegar too. Fermenting still pickles as it builds up lactic acid instead of acetic acid (which, funnily enough is a fermentation of sugar to alcohol to acetic acid). I guess lactic acid is a smoother 'sour' though compared to the bitey vinegar. I can't stand cucumber pickles, especially dill, but I love sauerkraut (stupid taste buds).