Add hibiscus flowers and remove from heat. Allow to steep 5-10 minutes, then strain.
Add sugar and stir to dissolve. If the sugar is taking too long to dissolve, turn on the heat again and heat 1-2 minutes to dissolve the sugar.
Add sweetened tea to a clean gallon sized jar. Fill with room temperature filtered water. Using a kitchen thermometer, make sure the tea is 75°-85°. (By adding room temperature water to the hot tea mixture it will be around 85°-87°, but it will cool down to room temperature.)
Add kombucha culture and 1-2 cups homemade kombucha (or starter culture and starter tea) to the sweetened tea. Secure a tea towel or coffee filter over the jar with a sturdy rubber band.
Place the jar in a warm area that is between 75°-85°. Cold temperatures cause mold, so a warm area is necessary for the success of your kombucha!
The kombucha will be ready between 7-21 days. Taste it at day 7. If it's too sweet, ferment it longer. I like to brew mine for 18 days.
Notes
*If using a kombucha starter pack you won't need homemade kombucha because the starter culture comes in starter tea.To sweeten the hibiscus kombucha and make it bubbly, you will need some bottles with flip top lids. I use 25 oz. bottles.Pour 2 tablespoons maple syrup, then the finished homemade kombucha into each bottle, leaving 1-2" head space. Let sit 3-5 days, popping the bottles each day to let out carbon dioxide. Taste each day to test its flavor and fizziness.