How long can I keep my tang drink in my sipper? I need to go for trekking with my colleagues and want to carry my pre mixed tang drink with me in my sippers. Is it advisable? Do you think if I mix the drinks according to my tastes they might react and affect me adversely? Can you send me some early replies because I really am in a hurry? Does keeping the drink for longer time in the sipper can cause some reactions?