The acidity or alkalinity of sparkling water is determined using the scientific pH scale, which ranges from 0 to 14. A value of 7.0 represents a neutral substance, such as pure water. Measurements below 7.0 indicate acidity, while those above 7.0 indicate alkalinity. The scale measures the concentration of hydrogen ions in a solution.
The Chemistry Behind Carbonation
The fizzy quality of sparkling water results from carbonation, a process involving dissolving pressurized carbon dioxide (CO2) gas into plain water (H2O). A portion of this dissolved gas reacts with the water molecules to form carbonic acid (H2CO3), a weak acid.
The chemical reaction is CO2 + H2O ⇌ H2CO3. The formation of carbonic acid introduces acidity into the water. This acid partially dissociates, releasing hydrogen ions (H+) into the solution. This increase in free hydrogen ions lowers the overall pH of the beverage, moving it toward the acidic side of the scale.
The Verdict Sparkling Water is Acidic
The scientific consensus is that sparkling water is an acidic beverage. Pure, unflavored sparkling water typically registers a pH between 4 and 5, a significant difference from the neutral pH of 7.0 found in still tap water. Naturally carbonated mineral waters, such as Perrier or San Pellegrino, may sit slightly higher on the scale due to their mineral content, often landing just below a pH of 5.
The acidity is often amplified in many consumer products. Flavored sparkling waters or those containing added ingredients like citric acid can have a much lower pH. For example, lemon-flavored sparkling water can register a pH as low as 3.0, comparable to some soft drinks. This low pH results because the added flavorings themselves are often acidic.
Health Implications of Low pH Consumption
The mild acidity of sparkling water presents a primary concern for dental health, specifically the erosion of tooth enamel. Enamel begins to demineralize, or soften, when exposed to an environment with a pH of 5.5 or lower. While plain sparkling water hovers near this threshold, flavored varieties with a pH of 3 or 4 pose a higher risk of erosion over time.
The potential for damage depends largely on consumption habits, such as the frequency and duration of exposure. Sipping an acidic drink over a long period prolongs the time the teeth are exposed to the low pH environment. To mitigate this effect, experts suggest using a straw to bypass the teeth or consuming the drink alongside a meal, which helps neutralize the acid.
A common misconception is that drinking acidic water will alter the body’s overall systemic pH. The body maintains its blood pH within a narrow range of 7.35 to 7.45 through robust regulatory mechanisms. The lungs regulate acid by exhaling carbon dioxide, and the kidneys excrete excess acid via urine. The acids introduced by beverages are quickly buffered and neutralized, meaning sparkling water does not affect the body’s internal acid-base balance.