I usually put all my kimchi in the fridge except for a little bit in a small container. I like fresh kimchi, so this way the kimchi in the fridge ferments slowly and stays fresh, while the smaller container ferments faster and gets sour. I use this sour kimchi for making things like kimchi jjigae where sour kimchi is better. Then, when the small container is empty, I fill it up again with kimchi from the big container. It takes a little management, but experiment and you’ll get the hang of it!