PH increase in Coke.?

Question

I am doing an experiment in biology that involves the placement of teeth in solutions of different drinks. One of the indicators measured was pH, and I am trying to justify why Coke's pH increased. I have already suggested the liberation of alkaline ions present in the teeth, but i am unsure of any others ways the pH could have been made more alkaline.

Coke had in increase from pH 2.97 to 3.95, an outstanding value in comparison to the other solutions.

Thanks.

Answer 1

Another possibility might be the absorption of CO2 from the atmosphere.