RC Cola is the most acidic soft drink, according to the Richmond Institute for Continuing Dental Education. It has a pH level of 2.387, making it highly acidic. Cherry Coke has the next highest level of acid with a pH of 2.522, and regular Coke follows at 2.525 pH.
Even though RC Cola is the most acidic, other soda drinks are very acidic. As most sodas are acidic and thereby damaging to tooth enamel, it is best to drink them in limited quantities or not at all, states Livescience. Drinking soda through a straw may help protect tooth enamel from having direct contact with the acid, thereby avoiding some of the damaging elements of the acid.