Ok i do long endurance rides in winter at even temperatures -30C. anyways been using the insulated water bottles with hot liquid, does work, more less liquid freezes takes longer.

Anyways i read in one post, people use vodka? i dont want to get drunk while on a ride, but is it true alcohol like vodka in water bottle, mixed will prevent a freeze?
also how should i mix the vodka, as not to inhibit performance on bike or be a drunk, thanks.