Add the water and the tea bags to a large pot, stirring to submerge the tea bags. Then add the sugar and stir to completely dissolve.
Cover the pot and let the tea cold brew for 8-24 hours.
Once the tea has brewed, remove the tea bags with a slotted spoon. Transfer the tea to a gallon jar, leaving enough room for the SCOBY and kombucha starter.
Add the kombucha starter to the tea, then add the SCOBY to the jar. It may float and it may sink, either way is ok.
Cover the jar with cheesecloth and a rubber band and put it in an out of the way spot away from direct sunlight.
The kombucha will take anywhere from 1-3 weeks to fully ferment. It will taste slightly vinegary and will have formed a new baby SCOBY on the surface of the kombucha.
Reserve the SCOBY and 2 cups of kombucha to start a new batch.
You can bottle and refrigerate the fermented kombucha and enjoy it as is, or you can do a flavored second ferment in order to create a delicious, probiotic-rich soda.
Notes
This recipe makes cold brew green tea for a lighter, less bitter result. Feel free to use a traditional hot brewing method for the green tea, just make sure the tea cools completely to room temperature before adding the SCOBY.
Green tea kombucha is a nice alternative to black tea kombucha because it yields a lighter flavor and is perfect for floral and whole fruit kombucha second ferments.
Since green tea contains less caffeine than black tea (SCOBY’s feed off of sugar and caffeine), you can give the SCOBY a boost by making a batch with black tea every 3-5 feedings, or you can use a 50-50 mix of green and black teas.