I have neglected my sourdough culture in the back of the fridge and it looks and smells beyond recovery! I have water kefir (sugar, water & kefir grains/culture) which I regularly ferment for a probiotic drink... can I use this to make a super quick sourdough culture - e.g. mix flour and water kefir and leave overnight??? I have never made my own culture before. Has anyone done this using water kefir and how would you go about doing it?