Kombucha Makers Unite; Where to ask and be answered in Recipe Sharing Posted July 24, 2013 Too much sugar in the bottles? (Either from the fruit you added, or your original brew) Too warm where you're storing the bottles? I wouldn't think the amount of room left at the top would make a huge difference. I'd go with the temperature they're being stored at (as mine hasn't been exploding). Maybe put them in the fridge after day 2 next time?