If using frozen blueberries, allow them to thaw first so that it's easy to smush them into bottles.
Line up 4 (25 ounce) bottles with flip top lids or other air tight bottles.
Smush ½ cup blueberries and 2 tablespoons minced ginger 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.
Refrigerate when you are happy with the amount of fizz and flavor. Strain if desired.
Notes
Use freshly made homemade kombucha that has not been refrigerated yet.