Q
I like to drink seltzer water — I make it at home from tap water, with a CO2 cartridge. A neighbor told me that she’s asked a million dentists and they all agree that seltzer is very bad for your teeth. I believe she’s thinking of carbonic acid. It’s not like I have a tank of seltzer hooked to me at all times…really, is it that bad to drink seltzer?
A
As you suggest, carbonated drinks come in many varieties, and the effect on teeth depends on which one you choose.
You can buy naturally carbonated mineral waters from springs in Europe for a premium price, or you can carbonate tap water at home for much less. The key difference between these options is acidity and the minerality of the water.
If you’ve read the blog, you know I prefer San Pellegrino for its relatively alkaline effect in the mouth compared with many other fizzy options.
So what makes a bubbly drink good or bad for your teeth?
What’s the Difference Between Soda and Sparkling Water?
Carbonated water—also called sparkling water, seltzer, or fizzy water—is plain water with carbon dioxide dissolved into it. That dissolved CO2 forms carbonic acid, which gives fizzy drinks their tart taste and is the defining characteristic of most soft drinks.
That acidity is what matters for tooth health: more acid can soften enamel and, over time, contribute to decay if exposure is frequent or prolonged.
Carbonic Acid
Home carbonation is simply adding CO2 to water in a sealed bottle. Commercial “club soda” may be identical to plain carbonated water or include small amounts of salts like sodium bicarbonate, potassium sulfate, or similar additives to mimic a slightly salty mineral taste.
Some mineral waters are naturally carbonated at the source, while others are artificially carbonated and then bottled. The acidity of a carbonated beverage is influenced by how much CO2 is dissolved—the partial pressure of the gas.
Typical bottled sodas produce a fairly low pH (around pH 3.7), which tastes sour and is acidic enough to erode tooth mineral over time. Repeated acid exposure can dissolve calcium from enamel, creating weakened areas and ultimately cavities.
I tested several everyday beverages using pH test strips. Natural mineral waters such as San Pellegrino tested in the low-acid to neutral range (approximately pH 6.8–7.7).
Recommendation: Test your homemade seltzer with pH strips to be sure. The amount of CO2 you dissolve will determine how acidic it is. If your carbonation level is low, acidity may be minimal; if you over-carbonate, the beverage will be more acidic.
For overall health, a neutral to slightly alkaline beverage is preferable for the mouth. Some acidic foods (for example, citrus) can become alkaline after digestion, which is fine systemically but they still can damage tooth enamel while in the mouth. When consuming acidic foods or drinks, sip water alongside or rinse afterward to reduce the time acid spends on teeth.
Stomach acid is far stronger than anything we normally consume, so once food and drink pass into the stomach the higher acidity is not an oral concern. In the mouth, however, a neutral or slightly alkaline pH is likely best because it makes the environment less favorable for the bacteria that cause cavities.
Based on pH alone, some bottled waters rank better than others: San Pellegrino (around pH 7.7), Fiji (pH 7.5), Evian (pH 7.2) and Volvic (pH 7.0) are fairly neutral, while Perrier measures more acidic (around pH 5.5).
I can’t tell you exactly where your homemade seltzer will fall without testing, but it’s easy to check with affordable pH paper. That will give you a clear idea of how much acid is contacting your teeth and whether you should adjust your carbonation level or drinking habits.
In short: not all sparkling waters are equally harmful. Frequent exposure to highly carbonated, low-pH drinks increases risk to enamel, but mildly carbonated or neutral-pH mineral waters are much less problematic. Test your seltzer, sip water with acidic foods and drinks, and avoid constant sipping of strongly carbonated beverages to protect your teeth.
Mark Burhenne DDS
Learn More:Dry Mouth: Consequences, Causes, and Treatments