Here’s where we bring in the white coats. All that fizz comes from carbonic acid, which makes seltzer slightly more acidic than still water. Does that mean it’s dissolving your enamel? Not exactly.
Plain seltzer has a pH around 4-5, which is far less erosive than soda, fruit juice, or even orange slices. The real villain is added flavorings with citric acid, which can push that pH lower.
Practical tip: Use a straw to minimize contact with your teeth. And never swish seltzer around your mouth like a fancy wine tasting—your enamel will thank you.