Storing Kava in the fridge for a week is fine (my experience)
I've been drinking kava for a few years and playing around with how I store it, especially since traditional kneading drys out my hands too much. Contrary to a lot of common advice, I don't believe that kava is only good for 2-3 days. Here are some ways I have experimented:
2 min blender medium grind, strained by hand, kept in fridge for 1 week
2 min blender medium grind, no straining, kept in fridge for 2 weeks
Traditional (10 min by hand), kept in fridge for 1 week
In all cases, the kava tasted the same each day and I didn't notice any change in subjective potency (I measure out my doses to the gram). Even the traditional kneading one didn't develop anything bad, though I wouldn't risk it past 1 week. In each case, the kava did settle at the bottom, but I just shook it for a bit to mix things back. The kava did not congeal or anything like that either. I have tried each of these methods with several kava strains from different stores.
Anyway this is just what worked for me and I hope this information helps other people who were curious. Going forward, I will probably just do #2 out of pure laziness, but note that one might be hard on the stomach regardless due to the root fibers present, either start slow or introduce more fiber in your diet if attempting that.
DISCLAIMER: please use common sense, doing this still carries inherent risk, I don't know exactly how cold your fridge is, how many bacteria are on your hand when you make your kava, or even if your kava provider is clean.