Mix: In a large glass bowl or pitcher, stir together pumpkin puree, spices, ginger, vanilla, and about 1/2 cup of the kombucha.
Bottle: Transfer kombucha into fermentation bottles* (I used 2 quart-sized bottles), leaving about 3 inches empty at the top. Pour in pumpkin mixture. Add cinnamon sticks to each bottle. Seal tightly.
Ferment: Place in a dark, room temperature area for 3 to 10 days, until it reaches the carbonation level you like. This process will go faster in warmer climates, and slower in cooler climates.
Enjoy: The pumpkin creates some sedimenting in this kombucha, so you can strain that out with a sieve or cheesecloth (optional), then chill in the fridge before serving. Can be stored in the fridge, tightly sealed, for several weeks.
*If this is your first time brewing, it may be helpful to use a plastic water bottle as a gauge. Fill a disposable plastic bottle with kombucha (leaving 2 inches empty at the top). When this bottle becomes rock hard, you’ll know the glass bottle are also ready. This will help you gauge how quickly kombucha brews in your climate and will prevent bottle explosions.