After opening, I do recommend storing them in the fridge for optimal benefits to maintain the integrity of the good bacteria that they contain. (heathermcclees.com)
However, if you need to take a break, then store them in the fridge in sugar water and change it out every 7 days to keep them fresh. (kombuchakamp.com)
You just store them in the fridge if you make them the night before? (homecookingmemories.com)