So make little kava ice cubes, and when ready to consume, put them in some lukewarm or warm water.
Drink it as they melt. It may be weak kava, but it's convenient, but you get the same effects if you drink
enough, and has self-contained water to keep you hydrated !
Or what you could do is make some extra strong grog to freeze into cubes.
That way when it dissolves in the warm or lukewarm water, it won't be so weak.