To make a gallon batch of kombucha, start by brewing about a half gallon of black tea. Add several spoonfuls of loose leaf tea to the hot water, but you can also use tea bags if you wish.
Let it steep for a little while, then strain the tea into a gallon glass jar
While it’s still warm, add sugar to the tea and stir to dissolve.
Add cold water until the jar is about 3/4 full.
Add your SCOBY and starter kombucha to room temperature tea.
Cover the jar with a clean towel or cheesecloth and a rubber band and put in a warm and out of the way spot in your kitchen. Do not disturb during fermentation.
After a week or two a whole new SCOBY baby will have formed on the surface and the liquid should taste somewhat vinegary, just like kombucha! Set aside your SCOBY and 2 cups of liquid for your next batch.
Hibiscus Second Ferment
Prepare hibiscus tea and add it to the kombucha.
Transfer the hibiscus kombucha mix into flip top bottles using a small funnel.
Seal the bottles and let them sit at room temperature for a few days. Open the bottles to let the gasses escape once a day. (This is called "burping.")
Test one and see if it is to your taste. Once it is nice a bubbly to your liking, put the bottles in the fridge and drink whenever!
Notes
Many recipes I see online call for using white sugar in kombucha, but I’ve always used raw sugar with no problem.