osubckys, I have run in to the same thing but I personally think it has to do with taste. I think that you get used to one flavor and when you switch to another your taste buds have to adjust. At least that is with me. as for going stale or bad i have not had that happen to me. i shake my juice before I drip, and keep the juice i don't use in the refrigerator. hope i helped a little.