I'm brewing two batches of kombucha, one with a fairly old mushroom that I had in the fridge and one with a newer one from a friend. The one with the old mushroom is growing spots of mold on the surface of the liquid. It's been brewing for a week. Some questions:
Is this because the mushroom is old? I think it was in the fridge for several months, stored in a clean sealed jar with just a little bit of kombucha. It looked, smelled and felt just fine when I got it out.
Maybe it's because I tried to 'fancy up' that batch with ginger? I added about five slices of fresh ginger to the boiling water and left them there through cooling and strained them out when I took out the tea bags and added the mushroom. (I will be bummed if this is the reason! My friend made some absolutely heavenly ginger-infused kombucha and I want to replicate it!)
Maybe it's because the kombucha was not properly covered all the time? I have it on the kitchen counter, covered with an old (clean, obviously!) cloth diaper. My littlest is now old enough to reach the back of the counter from a stool and has pulled the cover off a few times. But the other batch was uncovered, too, and seems fine, so this probably isn't it.
Lastly, what can I do? I sort of assume I'll just have to dump the whole thing, mushroom and all, but what a shame!