Carbonated Foam

Brian_Sysun_82296

I ate Craigie on Main in Boston last weekend and for dessert my plate came with a mind blowing root beer foam. Im pretty sure I saw the young chick on garde manger dispense it out of an isi whip but thats where my intel ends. It literally tasted just like root beer, except in a stabilized foam that fizzed when it hit your tongue. In my head Im thinking in any instance you would have to stir in some sort of hydrocolloid, agitating the carbonation and making the soda flat, thus requiring the recharging with CO2. I then thought about making a sort of root beer glacee, stabilized with gelatin and charged with CO2. Just curious if anyone had any insight or knowledge on the topic before I started trying this out. Thanks.