My kombucha developed mold the week before last and I dumped it but after doing more research I realized my mistake. I rescued the kombucha mother from my sink drain (yes, really) and washed it under the tap (chlorine, oops!). I tore off a tiny chunk and added it to a new batch of tea.
After waiting for a while I noticed cloudy lumps hanging around on the bottom of the fermenting jars. I was again concerned but, as before, research suggested that sometimes the mother sinks and everything is fine.
There were again spots of mold developing on the liquid, but I scooped them off and added two spoons of vinegar to each jar to stave off the mold until the lactic acid bacteria could further acidify the drink. Finally, with no funny smells, I noticed a new mother forming on the top of the liquid.
I poured a glass, avoiding any lumps or pieces of the mother, and tried it yesterday. It was really good! Just like a dry iced tea but with an acidic kick to it, very refreshing. It was about 10 days fermenting, which may be a bit long. It would probably be sweeter and less acidic if I drank it sooner, but I wouldn't cut the time down much.
I used a black breakfast tea brewed strong and 1/4 cup of sugar per quart of tea. I didn't notice if there were effects from the caffeine.