We used the medium batch which was just right to make 11 bottles of grapefruit kombucha. We used a fresh (very dry) pre-squeezed grapefruit using 1/3 cup and 1 tbsp sugar.
For the large batch we made 13 bottles of plain kombucha using 2 tsp sugar per bottle.
We pulled the grapefruit at 4 days and there was barely a pop but there was just enough fizz to justify pulling it and putting it in the fridge. Was perfect.