JusticeZero

I have an insulated "polar bottle" I ride with with a liner said to be good at "keeping cold drinks cold". It seems to be a bit less effective at keeping hot drinks from getting frosty on a two hour commute, however... Does anyone know any good bottles I can put in a bottle rack that will keep some hot chocolate or whatever from turning into a frosty slurry on a cold day ride?

2manybikes

After ten years of testing I like the Thermos "Backpaking Bottle".
The ones in the middle with the orange button. You can drink one handed while riding you just push the button and the top hinges open. I've tried them all. YOu must have stainless steel vacum insulated bottles to do what you ask. The larger "Backpack bottle" will stay warm a little longer due to the increase of volume of hot liquid.

Google "vacuum flask".
Thermos does not sell it anymore but there are still some on line places that have some left. Try Campmore too.

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.

2manybikes

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.