I feel like a bacterial nanny some times. I move from room to room, tending to my little fermenting pots, trying to keep everyone happy and cozy. The vinegar gets a shake to introduce more oxygen, or a move to a warmer spot in the house to help the acetic bacteria ferment faster. The kefir gets a fresh splash of milk, the kimchi gets its gases let out, and the kraut pot needs regular topping up to keep its airlock sealed.
It's actually quite clever: as the scoby ferments the sugars in your tea, it increases the acidity as it produces acetic acid. To protect the more sensitive yeasts and bacteria from the rising acidity, the scoby produces a biofilm to protect itself. The scoby produces cellulose to shield itself, while allowing it to still ferment the tea!
The great thing about kombucha is you can use almost any tea (food fermenting author Sandor Ellix Katz actually had a friend use his scoby to make kombucha Mt. Dew). Right now Carla and I are using it to ferment red tea, so we can drink it at night without worrying about adding excess caffeine. But like other acetic acid producing bacteria (like vinegar mothers) the scoby needs warm temperatures of 70-85 F, which are hard to come by in our house in the autumn and winter. But our baby scoby seems to be pretty happy on top of the stove where it can soak up the radiant heat.
I still need to do more research to see if you can eat the scoby itself, so more to come!