Kombucha Mushroom

The kombucha "mushroom" is not a fungus. It's a symbiotic colony of yeast and bacteria.

When a batch of kombucha tea is fermenting, the mushroom you started with will grow a new mushroom on top. Usually the new mushroom will grow as large as the opening at the top of the jar. Mushrooms can be reused. However, I get my best results when I start my new batch with the new mushroom that grew on top of the old batch. You should be able to peel the new and old mushrooms apart. Don't worry if it tears. In fact, I usually use a clean pair of kitchen scissors to snip a section of my new mushroom. I usually like to have a starter mushroom that's about 1/4 the size of my jar opening. So for a 3-quart batch, I'll use a blob of mushroom that's about 3" across. For a 3-cup batch in a quart-size canning jar, I'll use a a piece of mushroom that's a little bigger than a half-dollar.

If you're trying to get multiple batches going at once, it's okay to reuse the old mushroom. But if the mushroom didn't sour the tea properly, it may be bad: throw it out and don't use the tea. If the mushroom gets black, it's probably spoiled. I have on occasion had a little black grainy stuff grow on the mushroom. I'll usually cut that part off and dispose of it. Sometimes I will gently wash the mushroom under running cold tap-water to remove those dark spots. Ideally, I want to keep the clearest part of the new mushroom.

Old mushrooms can be used in the compost pile, or buried at the feet of your tomato plants or corn seeds. I've heard it's a great fertilizer.