When you mix ice cream and a soft drink (like coke,) a reaction happens that creates a thick foam. I am assuming the foam id composed of carbon dioxide gas and milk curd, which is produced by the milk reacting with an acid.

Is the milk curd produced by the carbonic acid or the phosphoric acid? Is the carbon dioxide released by the added sugar, or another ingredient? Are there other important processes going on in there?

  • 3
    $\begingroup$ Just a guess, but I would imagine that the foam is caused by the effervescence of carbon dioxide (which was dissolved in the soda) made more rapid by nucleation on the ice cream. $\endgroup$
    – canadianer
    Jul 4, 2014 at 4:42