# Why does it hurt in the mouth when drinking carbonated beverages?

The typical explanation for the origin of the "sting" is that $\ce{CO2}$ turns into carbonic acid (reddit, yahoo), however the "explanations" there are incomplete.

The answer I'm looking for would cover:

1. Is conversion to carbonic acid is really the case here? And what are the original compounds the same enzyme(s) is used for?
2. Why is there no "sting" from $\ce{CO2}$ found in air?
• articles.latimes.com/2013/aug/22/science/… – CoffeeIsLife May 19 '17 at 2:08
• "The earliest clues that carbonic acid, not bubbles, were responsible for this sensation came from mountaineers’ accounts of the “champagne blues.” After pouring a bottle of celebratory champagne at the summit, mountaineers who had taken medication for altitude sickness disappointedly remarked on the drink’s flat taste — despite its fizziness. It turns out the medication blocked the enzyme that converts carbon dioxide into carbonic acid." – CoffeeIsLife May 19 '17 at 2:10
• @QuantumAMERICCINO thanks. They don't mention why this is not happening with air. – Sparkler May 19 '17 at 2:16
• Hmm interesting. According to chemistry.stackexchange.com/questions/9067/… , a can has 2.2 g of CO2 in a 355 mL can of Coke. Thus, it would be roughly 6000 ppm. Atmospheric CO2 ppm is around 400 ppm. Thus, it seem like concentration is what causes it. Maybe it has to do something with the medium. Maybe the CO2 has to be solvated in an aqueous medium for the enzyme to reach it. – CoffeeIsLife May 19 '17 at 2:42
• Isn't it a coincidence that the user "Sparkles" is asking about carbonated beverages, one of them being "sparkling water"? – Pritt says Reinstate Monica May 19 '17 at 15:05