While drinking my hourly Pespsi® (I am addicted to caffeine.), I got to thinking about carbonated soft drinks. Often the bubbles are referred to as “refreshing.” But when I hold a mouthful for about five seconds, I get moderate pain from the soft surfaces in my mouth.
Why does it hurt? I image it is because the bubbles are made of carbon dioxide, which is a poison. Or is it the process of the bubbles forming that cuases pain?
How did carbonated drinks ever become so popular if they cause pain? Maybe it is because caffiene is addictive. That’s why I drink it, I think.
A quick wag: CO2 combines with water to form carbonic acid. The longer you hold Pepsi in your mouth the longer the two have to combine. This assumes that there is water in your saliva that is free to combine with the CO2. Your tongue is sensitive enough to the acid to smart when it comes in contact with it for a relatively long time.
I think to test this theory we fill a large vat with carbonic acid and push the annoying Pepsi girl in it.
I would agree that acid is the cause of the discomfort, but I don’t think carbonic acid is the culprit. (I’m not a chemist, though, so my opinions are just that.) I think most of the CO[sub]2[/sub] bubbles out of solution rather than forming carbonic acid, which is a very weak acid in any case. I would guess that the discomfort actually comes from the phosphoric acid that Pepsi (and Coke) add to their cola. It’s listed on the label.
A possible experiment, which I’m too lazy to do, would be to take a swig of defizzed Pepsi and see what happens.
Alright, it may not be a poison, but carbon dioxide does have adverse affects on humans.
I removed most of the carbonation in a half-cup of Pepsi® by swishing it around in the glass. (Why does swishing it remove carbonation?) When I put in my mouth it didn’t hurt nearly as much as regular Pepsi®. In fact, I kept it in my mouth the entire time I wrote this message.
So, does that mean it’s from the bubbles? And why did carbonated drinks catch on if they hurt so much?
By the way, swallowing saliva-saturated, body-temperature, flat cola is pretty disgusting.
Now, I know you’re all dying to hear about my bladder, but this is actually in some way relevant. After a particularly torturous flight across the Atlantic during which one of the bathrooms was out of service, I asked my doctor why sometimes I couldn’t empty my bladder completely, but wound up trotting back and forth to the toilet for an hour or so, every 10 minutes. She said my bladder was spasming, and that certain irritants can cause this, including caffeine, alcohol, and carbonated beverages. So whatever irritating effect they have in your mouth apparently carries through to the other end of the system as well.
So, I guess I shouldn’t have had that rum & Coke before flying, huh?
I don’t think water forms carbonic acid in your mouth, there is plenty of water in pepsi to do it in the can.
My guess is that the nucleation of the bubble causes the pain, much like cavitation causes boat prop’s and pump impellers to wear away.
Cavitation is caused by water (or a liquid) changing into a gas because of a pressure change. when a boat prop is ‘spinning’ too fast the liquid water actualy boils at normal temps right on the prop blade. this boiling has a nasty habit of causing the prop tMG St.
Wood Thrush, perhaps you just have a particularly sensitive mouth? I’ve never found carbonated beverages painful-- In fact, I prefer them with more carbonation, rather than less.
K2Dave–cavitation is NOT the “formation” of bubbles. The “formation” of bubbles is in itself not damaging. What is damaging is when those bubbles RECONDENSE back to the liquid state quickly. The effect is a tiny implosion and shock waves. This is what “Cavitation” is, and it can destroy pumps and bent propellors and such in seconds.
As far as you other guys–carbonated beverages do indeed hurt my mouth and throat–but only when it is fully carbonated. If I shake my drink a little to get rid of some of the CO2, I find it more drinkable (carbonated water is water that is SUPERSATURATED with CO2, that is, the water is subjected to CO2 under high pressure, and the CO2 dissolves into the water. Reduce the pressure, and the dissolved CO2 wants to break out, but can’t unless there is agitation or nucleation sights.)
In the interest of science, somebody should put some tonic water or club soda from a NEW bottle into their mouth and see if it hurts. I would, but all the tonic water I have is flat.
Also–CO2 can be an irritant to the mucous membranes. Who here hasn’t burped through their noses after drinking a coke?
For the most part, the only adverse effect that CO2 could have on you is depriving you of oxygen, and it would be no better at doing so than nitrogen or helium.
I think k2dave already got this one. The pain does not come from carbonic acid (as has been stated, carbonic acid is already present in the drink), but rather, the bubbles rapidly forming in tiny crevices in your mouth. Just before the bubble forms in the crevice, the liquid and dissolved gas are taking up the entire volume of the small crevice. When the bubble forms, it rapidly increases the volume of material contained in the crevice. This increased volume causes a localized increase in pressure. The pressure will push on the crevice (your flesh) until it can escape to a lower pressure area (the atmosphere of your mouth), thus causing pain.
Also, I think the reason that some burps burn your nose is that they bring HCl up from your stomach. I work with, and make dry ice sometimes, and have never experienced a burning sensation in my nose from the excess CO2 around me.
[K2Dave–cavitation is NOT the “formation” of bubbles. The “formation” of bubbles is in itself not damaging. What is damaging is when those bubbles RECONDENSE back to the liquid state quickly. The effect is a tiny implosion and shock waves. This is what “Cavitation” is, and it can destroy pumps and bent propellors and such in seconds. ]
Thank you for that correction, this is how cavitation works.
I have a bottle of tonic water, but not ready to open it yet. why do you expect this to be diffrent?
I believe that this is not correct. High CO2 levels in the presence of normal O2 levels is a poison. See the movie Apollo 13 for a pop culture example. The astronauts had plenty of oxygen, but the high co2 levels were making them sick. This is the reason for the use of the co2 scrubbers.
I think the experiment should take place at the next Doper’s gathering. I suggest a bottle of cola, tonic water, Champagne, and a vat of dry ice.
Hypothesis The burning sensation is caused by the presence of CO2 in the beverage
Allow glasses of Pepsi, tonic water and Champaign to go ‘flat’ then refrigerate them to the same temperature of carbonated beverages.
Dip tongues into glasses of each, noting the presence or absence of stinging sensation. If it is present in
both samples of one product but not in either of the others, the source of stinging is likely the ingredients of that product. If the stinging sensation is present in the carbonated beverages only, then it is likely that it is the CO2 that is causing the sensation.
Drink the Champagne
I am not sure how to test for the mechanism of the sensation. But I do think that it should involve the little Pepsi girl, the vat of dry ice, and a chorus of Einstein lookalikes saying ‘well, duh!’ as they apply force to her oh-so-cute posterior. And Champaign drinking.
