Originally Posted by
Machka
Put a sock on it. Literally. I put socks on my bottles and soak the socks to keep my water cool in the summer. Then in the winter, I keep the socks dry and they help keep my water from freezing as fast.
I don't remember you mentioning this, maybe you did. Did you experiment with stainless vacuum bottles? I can't remember ridng much below +10f around here. I know you go down to -40.