The pH of carbonated beverages: Effects of time and dilution

Objectives: Parents are generally informed by dentists about the harmful effect of carbonated beverages to the teeth of their children. However, some parents believe that when the carbon dioxide has been blown off, the acid concentration decreases and becomes safe. It is also a common way to dilute the beverage with water to reduce the acidity. The aim of the present study was to measure the pH changes of 15 carbonated beverages with time and dilution ratios. Methods: The pH measurements were carried out using a pH electrode connected to an Orion 720 A ion analyzer. All measurements were repeated 5 times using a fresh drink in each time to obtain a mean value. In the first step, 20 ml of each sample was placed into a test tube. The subsequent pH values after 1-50 minutes were measured. Then, a series of dilutions of each beverage ranging from ½ to 1/50 was prepared using water as the diluent and their pH were measured. Results: Most of the beverages used in the study demonstrated pH values within the range of 2.6 to 2.8 during 50 minutes. However, Cola Turca Light (CTL) had the highest pH value of 3.036±0.085 after 1 minute and rose up to 3.156±0.032. At ½ dilution ratio, Adese had the lowest (2.769±0.132) whereas CTL had the highest (3.237±0.066) pH value. Le Cola light had the highest pH value (5.437±0.681) at 1/50 dilution. Conclusion: It is concluded that the pH values continued to be under the critical pH (5.5) even though the carbon dioxide was blown off and the beverages were exposed to air during 50 minutes. The measured pH changed very little with increasing dilution ratios and remained under pH 5.5 although diluted with water to a 1/50 ratio.