Boil 1 gallon of water
Add 1 cup sugar and stir until dissolved
Add 8–10 black tea bags or 2 tablespoons loose black tea
Steep for 10–15 minutes
Remove tea bags or strain out tea leaves
Let the tea cool to room temperature
Pour the cooled tea into a clean glass jar
Add 1–2 cups plain unflavored starter kombucha
Add 1 SCOBY
Cover the jar with a breathable cloth or paper towel
Secure the cover with a rubber band
Place the jar in a warm, dark spot
Ferment for 7–14 days
Taste after 7 days
Ferment longer if you want it less sweet
Remove the SCOBY and 1–2 cups liquid for the next batch
Bottle the kombucha
Add optional flavorings if desired
Seal the bottles
Let the bottles sit at room temperature for 1–3 days for carbonation
Refrigerate before drinking