How long can I keep my frs energy drinks mixed with tang drink in my sipper? I need to go for trekking with my colleagues and want to carry my pre mixed frs energy drinks 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 am in a real hurry? Is it fine to keep the drink for a longer period of time in the sipper, or is it liable to cause some reactions?