You make kombucha by brewing tea, adding sugar, and adding a starter of some sort. Usually the starter is part of the “mother” (SCOBY) from a previous batch of kombucha but I have just found that adding a little bit of store-bought kombucha also works. I added two tablespoons of GT’s kombucha and two tablespoons of Revive kombucha to sugared tea. Two weeks later there was a perfectly good mother on top of the tea. This is useful to know even if you have a mother if you want to make kombucha slowly. In The Art of Fermentation, Sandor Katz advocates adding a bottle of kombucha into your sugared tea if you don’t have a mother.