Line up 4 (25 ounce) bottles with flip top lids or other air tight bottles.
Pour ¼ cup maple syrup, and ½ teaspoon vanilla bean seeds (or ½ teaspoon vanilla extract) into each 25 ounce bottle.
Using a funnel, pour freshly made homemade kombucha into each 25 ounce bottle leaving 1-2" head space.
Let bottles sit out (at 75° - 85°) 3-5 days, making sure to pop the lids each day to let out the pressure of the carbon dioxide. Taste each day to test its flavor and fizziness.
Video
Notes
You can also make this recipe using vanilla simple syrup. I tried with both ¼ cup and ½ cup simple syrup, and both were good.