Carbonation is the process of dissolving carbon dioxide in water, usually by putting the carbon dioxide under high pressure. When the pressure is reduced, the carbon dioxide is released from the solution as small bubbles, which cause the solution to "fizz" when opened.

[Sorry to ruin your miracles, Gamzee. He's not really paying attention now that he's got a third of the pie devoured. He's just eating. And talking. And yanking that pie tin from your hands so he can lick that green swill straight up. Cutting out the middle man, or in this case, finger.]