"Do you want something to drink?"
Translation:Haluatteko jotain juotavaa?
At least pragmatically speaking, it makes no discernible difference whatsoever. I don't know of a great empirical way compare their frequency of usage, but at least judging by the number of google search results, "haluatko jotain juotavaa" is about 2.5 times more common. That's also in the ballpark of what I would estimate on the basis of my intuition.
It seems that if I can replace the word with 'sweet' or 'soda', I'd use juotava.
Minä haluan jotain juotavaa (I want something 'to drink').... which I can say (I want something sweet).
Where as if I want to say Minä haluan juoda mehua (I want to drink juice) .... Juoda comesa after haluan (I want TO DRINK).
I hope this helps.