Is there any way to prevent my hydration system from freezing?
Why yes, pour in a shot of Prestone. Lots of riders do this every year, hence the slogan, "Hydrate and die." Dr. Flake, who doesn't have any Prestone because his Subaru Justy has been yard-bound (temporarily!) for a couple years, prefers less-expensive anti-freezing measures, such as blowing water out of the nipple back into the bladder (not exactly sanitary), keeping the hose inside his jacket (a bit inconvenient), and filling the reservoir with hot Gatorade (sooo tasty). That said, Kwanzaa is fast approaching, and the good doctor hopes to harvest a CamelBak Thermal Control Kit, which comes with a rubber mouthpiece cover and foam-insulated tube sleeve. It shields a hydration system's exposed bits as well as anything. Which is to say, it works sometimes.