Carbonated drinks are produced by a process called as carbonation. Carbonation occurs when carbon dioxide is dissolved in water or any other liquid. Carbonation gives the fizz to the carbonated water or any liquid to which it is added. In most soft drinks the carbonation gives the drink its bite. The fizzy taste that comes is due to the carbonic acid that causes a slight burning sensation. Carbonation also reduces the pH of a liquid. Carbonated soft drinks are often seen to be more acidic, even more than distilled water. Some studies suggest that the acidic nature of these drinks can harm dental health.
The carbonation process can be natural when natural gasses are built up during processes like fermentation. When carbonated soft drinks are made carbonation gives it that bite. It is often a misconception that the bubbles present give the bite to the drink. However, the carbonic acid that is created gives us that fizzy taste. In colas like Pepsi the bite comes from the phosphoric acid but which does not cause it to have that fizz. Moreover due to carbonation the availability of free oxygen in the soda is reduced. This can help reduce the pH of a liquid to some extent. The pH of most carbonated drinks is around 2.8 to 3.0 which means they are acidic in nature. 7 is neutral pH which is not harmful. However, as you move down to 6 or 5 and so on it makes that product acidic. Considering the colas have a pH of around 3.0 it means it is quiet acidic and can be harmful for your body. Effervescence is the release of gas from the drink. In colas or beer when dissolved carbon dioxide is depressurized it forms bubbles and makes the fizzing.
Some experts feel that such pH levels change the pH levels of our body which may not be as healthy. Moreover the acidic nature of carbonated drinks and soft drinks can be harmful to your teeth. It can cause erosion of tooth enamel. Some dentists advise drinking with a straw to avoid contact with the teeth. Soft drinks with high pH and other acid foods may lead to acidic food deposition around the joints and organs which can be harmful to the smooth functioning of the body.
The pH levels of various colas and soft drinks may vary. For Coke it is around 2.525, Diet Coke 3.289, Pepsi 2.530, Diet Pepsi 3.031, Cherry Coke 2.522, RC Cola 2.387, Mountain Dew 3.229, Diet Mountain Dew 3.365, Dr. Pepper 2.899, Diet Dr. Pepper 3.169, 7-Up 3.202, Diet 7-Up 3.706, Sprite 3.298 and Mug Root Beer 4.038. It may be noted that the pH levels of Diet drinks are in the same range.
When exposed to air carbonated drinks become flat. They lose the fizz and may taste a bit different. The pH levels may change towards the neutral levels but the difference may be very small. The change may be insignificant and may not make soft drinks any less acidic. It is for you to decide whether to drink such carbonated drinks considering the pH Levels which indicate their acidic quality.