Coke zero and ice cream effect?

Question

I was going to make a rootbeer float, but we only had coke zero. So Im eating a coke zero float, and i found that the soda made a hard crust around the ice cream, does anyone know why?

Answer 1

Any cold beverage does that...even root beer.  The liquid is warmer than the ice cream so it melts and then refreezes and creates a shell.

Answer 2

The coke zero is probably warmer than the ice cream so there's a hard shell of ice cream. I've had this before and I've noticed it does that with most sodas.