Question

what is the ingredient in an energy drink that makes it bubble

Answer 1

CO2

Answer 2

CO2 dissolved in water under high pressure forming H2CO3(carbonic acid)
When the drink is open due to pressure difference solubility of CO2 reduces considerably and it escapes out as effervescence

Answer 3

what about the phosphoric acid? I was convinced, that beside acidity regulator, does the bubbling effect. Another answer would be the addition of a foaming agent.

Answer 4

carbon acide