[AhBeng]

Coca Cola may be plotting a new version of Sprite that actually chills itself upon opening. Apparently, the drink has to be kept at a specified temperature before being snapped up, and once the oh-so-thirsty consumer pops the top, "a mechanism inside creates ice made from the drink, so it is not diluted." Reportedly, the beverage would sensibly be called Sprite Super Chilled, and if it does indeed hit the UK (and prove successful) by "early next year," the technology could then be passed along to Coke, Diet Coke or even "super cold alcoholic drinks, particularly beers."

Now, bearing in mind that unlike the ready-to-use-cooling-packs already available in the market today, we can't have poisonous chemicals (excluding coke itself, that is) in our soft drinks to kick start the endothermic reaction to form the ice. So the question is, how do they do it?


More from Google :
http://www.google.com.sg/search?hl=en&safe=off&q=coca+cola+self-chilling+soft+drinks&meta=

[DevaDevil]

apparently it's the bottle that will cool on the inside when opened, the drink will chill (form ice) as result - so no "endothermic drink"

Don't know how the bottle works just yet, and I am not really in the mood to dig for it (even though I assume the patent would be available to see)

[P]

I am not really in the mood to dig for it (even though I assume the patent would be available to see)

Likewise  -  but just speculating....   a release of gas at pressure through the drink could chill it via the adiabatic expansion of said gas, say Co2?  Maybee?


...hmm..  or come to think of it though -  maybe said expansion of gas would propell the drink out of the can into the air??    But maybe not?? 

[Yggdrasil]

A possible mechanism may be through pressurization.  Since liquid water is more dense than solid ice, high pressures will lower the freezing point of water.  So, lets say the drinks are pressurized such that the freezing point of the soda is -5^oC.  Storing the drinks at about 0^oC would not cause the soda to freeze.  However, once the pressure is released, the freezing point of the soda returns to the normal 0^oC, causing some of the soda to freeze.

(an interesting side note.  The formation of ice from water is an exothermic process.  So, these "self-chilling" drinks would actually slightly increase the temperature of the soda by causing ice formation!)