How to keep my hydration pack tubes and valve from freezing? I like to ride with a hydration pack when I mountain bike in the winter since all sorts of nasty stuff gets tossed up at my bottles.  However, I've had issues with the tube or valve getting clogged due to the water inside freezing during rides in the low 20s Fahrenheit (roughly -5°C). It's really hard to deal with this issue while you're out in the woods.

Is there anything I can do to prevent this from freezing so quickly?
The trick is to blow the water back up the tube and into the reservoir right after you take a drink.  This will keep your tube and bite valve from freezing.  This works well even at below freezing temperatures when skiing.