Freeze-proofing a camelbak

I usually snowboard with a camelbak since it’s an easy way to stay hydrated and it mostly stays out of the way. Unfortunately, when it’s particularly cold the hose can freeze. If the mouthpiece jams with ice it usually stays that way until I can get inside somewhere to let it thaw.

Somebody suggested adding some vodka to the water to stop it from freezing. Sounded reasonable.

My smaller camelbak has a capacity of 2L. 2 shots (60ml) of vodka (40% ABV) results in 24ml of alcohol in 2L, about 1%. Turns out the freezing point at 1% is still above -1C.

Getting the freezing point to -5C apparently requires 14% alcohol. Conveniently, this is easily achievable by dumping an entire 700ml bottle of vodka into a 2L camelbak and filling the rest with water.