wow fun! I'm gonna try. I brew kombucha and like that carbonation too. My understanding of Carbonation is that something eats the sugar and releases CO2 and thats how you get it fizzy. However, I've made batches of kombucha every two weeks for a year now and sometimes it is fizzy sometimes it is not. I give it about a week to work its bubble magic once I cap the bottles. Maybe it had to do with bakers yeast and not brewers yeast? I am beginning to wonder now if it has something to do with the amounts of sugar per kombucha culture. Maybe you didnt have enough sugar to naturally make it as bubbly as you wanted? Dont have an answer, but I'll let you know how my batch turns out. Have you tried root beer?