can I ask a not so simple question about CO2?

[SunnyD]

Does the CO2 in "premium" soda last longer than that of the generic stuff?

I ask this because every once in a while I get the urge for something other than water here at work, so I go to walleyworld across the street and grab a 2L bottle of their house brand (I really LOVE the grapefruit soda). And for $0.78 I sure as hell am going to buy the 2L over the $1.29 20oz.

Thing is, once you open a 2L bottle, basically the clock is ticking. I noticed that the soda tends to get flat within 24 hours, whether it's in the fridge or not. I'm not sure if it's perception or whatnot, but every time I've gone back to a 2L of Coke or Sprite or whatever, they seem to stay carbonated for 2 or 3 days before getting to the point of nastiness. Do they just diffuse the CO2 more or something?

 

[Hacp]

Originally posted by: SunnyD
Does the CO2 in "premium" soda last longer than that of the generic stuff?

I ask this because every once in a while I get the urge for something other than water here at work, so I go to walleyworld across the street and grab a 2L bottle of their house brand (I really LOVE the grapefruit soda). And for $0.78 I sure as hell am going to buy the 2L over the $1.29 20oz.

Thing is, once you open a 2L bottle, basically the clock is ticking. I noticed that the soda tends to get flat within 24 hours, whether it's in the fridge or not. I'm not sure if it's perception or whatnot, but every time I've gone back to a 2L of Coke or Sprite or whatever, they seem to stay carbonated for 2 or 3 days before getting to the point of nastiness. Do they just diffuse the CO2 more or something?

huh?

 

[spidey07]

No. Since the bottle is bigger there is much more air in the container than before where the CO2 was saturated in solution. The CO2 will move from the lidquid to the now larger volume of air in the container until it is equalized.

All this results in less CO2 in the liquid. A trick is to squeeze the bottle until there is little to no air in it and then cap it, that keeps the gas in the liquid.

 

[hanoverphist]

cap it off tighter. ive had 2L bottles still fizz after being in fridge after 2 weeks. once you open and close it 5 or 6 times is when i notice the bubbles not so bubbly

 

[Chryso]

He said name brand soda in 2 llitre bottle lasts longer than off brand 2 litre bottled soda.

 

[lxskllr]

It could be a style difference. Maybe grapefruit has less CO2 in the first place. I'd test using Coke, and generic cola to see if there's any difference.

 

[Crono]

Originally posted by: lxskllr
It could be a style difference. Maybe grapefruit has less CO2 in the first place. I'd test using Coke, and generic cola to see if there's any difference.

Yeah, better comparison. Even then, the generics may use more or less.

 

[FuzzyDunlop]

Originally posted by: spidey07
No. Since the bottle is bigger there is much more air in the container than before where the CO2 was saturated in solution. The CO2 will move from the lidquid to the now larger volume of air in the container until it is equalized.

All this results in less CO2 in the liquid. A trick is to squeeze the bottle until there is little to no air in it and then cap it, that keeps the gas in the liquid.

Awesome! someone should invent a bottle that does this automatically and yet still stands upright. maybe spring loaded?

 

[SunnyD]

Originally posted by: lxskllr
It could be a style difference. Maybe grapefruit has less CO2 in the first place. I'd test using Coke, and generic cola to see if there's any difference.

That could also be it, very true. I never stopped to consider this possibility.

 

[cheezy321]

I guess you learn something new everyday.

Thanks for the info spidey07!

 

[Crusty]

Originally posted by: FuzzyDunlop

Originally posted by: spidey07
No. Since the bottle is bigger there is much more air in the container than before where the CO2 was saturated in solution. The CO2 will move from the lidquid to the now larger volume of air in the container until it is equalized.

All this results in less CO2 in the liquid. A trick is to squeeze the bottle until there is little to no air in it and then cap it, that keeps the gas in the liquid.

Awesome! someone should invent a bottle that does this automatically and yet still stands upright. maybe spring loaded?

No need, just use a bladder system inside the bottle. Bladder fills up with the outside air as you pour out the drink and the bag acts as a barrier between the drink and outside air.

 

[sandorski]

The House Brands cut corners. Cheap/less flavouring, less CO2, less sweetener, etc etc.

 

[uclaLabrat]

Originally posted by: spidey07
No. Since the bottle is bigger there is much more air in the container than before where the CO2 was saturated in solution. The CO2 will move from the lidquid to the now larger volume of air in the container until it is equalized.

All this results in less CO2 in the liquid. A trick is to squeeze the bottle until there is little to no air in it and then cap it, that keeps the gas in the liquid.

Won't work. CO2 concentration in the liquid phase is a function of pressure (henry's law), and squeezing the bottle won't change the pressure. When the pressure increases inside the bottle, it will simply expand.

 

[uclaLabrat]

I'm willing to bet is has to do with pH. At lower pH, more of the carbonic acid will exist in the protonated form, and in that form it can't break down to CO2 and water, meaning more CO2 remains in solution as carbonic acid. Not entirely sure if this is correct, it could just have to do with the design of the bottles.

 

[spidey07]

Originally posted by: uclaLabrat

Originally posted by: spidey07
No. Since the bottle is bigger there is much more air in the container than before where the CO2 was saturated in solution. The CO2 will move from the lidquid to the now larger volume of air in the container until it is equalized.

All this results in less CO2 in the liquid. A trick is to squeeze the bottle until there is little to no air in it and then cap it, that keeps the gas in the liquid.

Won't work. CO2 concentration in the liquid phase is a function of pressure (henry's law), and squeezing the bottle won't change the pressure. When the pressure increases inside the bottle, it will simply expand.

It does work. Think it through.

 

[dullard]

Originally posted by: uclaLabrat
I'm willing to bet is has to do with pH. At lower pH, more of the carbonic acid will exist in the protonated form, and in that form it can't break down to CO2 and water, meaning more CO2 remains in solution as carbonic acid. Not entirely sure if this is correct, it could just have to do with the design of the bottles.

I was just going to post something along these lines but from the opposite angle. As the CO2 leaves, the pH changes. Low pH tastes good (usually sour, lemon for example). High pH tastes bad (bitter). Thus soda goes from the sour end of the scale towards the bitter end of the scale as the CO2 leaves. Now, are we tasting the CO2, or are we tasting the acidity of what is left? I don't know. But if what we taste is actually the acidity, a premium soda could have other acids or buffers to reduce the effect - that is, you just don't notice the absence of CO2 as much. This is just speculation on my part though.

 

[uclaLabrat]

Originally posted by: spidey07

Originally posted by: uclaLabrat

Originally posted by: spidey07
No. Since the bottle is bigger there is much more air in the container than before where the CO2 was saturated in solution. The CO2 will move from the lidquid to the now larger volume of air in the container until it is equalized.

All this results in less CO2 in the liquid. A trick is to squeeze the bottle until there is little to no air in it and then cap it, that keeps the gas in the liquid.

Won't work. CO2 concentration in the liquid phase is a function of pressure (henry's law), and squeezing the bottle won't change the pressure. When the pressure increases inside the bottle, it will simply expand.

It does work. Think it through.

I did. It doesn't, at least not to my understanding of chemistry. I'm more than happy to listen to arguments or data implying otherwise.

 

[uclaLabrat]

Originally posted by: dullard

Originally posted by: uclaLabrat
I'm willing to bet is has to do with pH. At lower pH, more of the carbonic acid will exist in the protonated form, and in that form it can't break down to CO2 and water, meaning more CO2 remains in solution as carbonic acid. Not entirely sure if this is correct, it could just have to do with the design of the bottles.

I was just going to post something along these lines but from the opposite angle. As the CO2 leaves, the pH changes. Low pH tastes good (usually sour, lemon for example). High pH tastes bad (bitter). Thus soda goes from the sour end of the scale towards the bitter end of the scale as the CO2 leaves. Now, are we tasting the CO2, or are we tasting the acidity of what is left? I don't know. But if what we taste is actually the acidity, a premium soda could have other acids or buffers to reduce the effect - that is, you just don't notice the absence of CO2 as much. This is just speculation on my part though.

As the acidity goes back up, it won't change the taste towards bitter, it should just basically get watered down and all you would taste is the sweetness from the sugar.

Typically, phosphoric acid is added to soda, and that is a bit more acidic than either citric or carbonic acid. So, overall I don't think the pH changes much, even if the CO2 leaves.

 

[Aluvus]

Originally posted by: uclaLabrat

Originally posted by: spidey07

Originally posted by: uclaLabrat

Originally posted by: spidey07
No. Since the bottle is bigger there is much more air in the container than before where the CO2 was saturated in solution. The CO2 will move from the lidquid to the now larger volume of air in the container until it is equalized.

All this results in less CO2 in the liquid. A trick is to squeeze the bottle until there is little to no air in it and then cap it, that keeps the gas in the liquid.

Won't work. CO2 concentration in the liquid phase is a function of pressure (henry's law), and squeezing the bottle won't change the pressure. When the pressure increases inside the bottle, it will simply expand.

It does work. Think it through.

I did. It doesn't, at least not to my understanding of chemistry. I'm more than happy to listen to arguments or data implying otherwise.

The mighty spidey07 has declared without evidence that this old wives' tale is true, therefore it must be true.

 

[Fayd]

Originally posted by: uclaLabrat

Originally posted by: spidey07

Originally posted by: uclaLabrat

Originally posted by: spidey07
No. Since the bottle is bigger there is much more air in the container than before where the CO2 was saturated in solution. The CO2 will move from the lidquid to the now larger volume of air in the container until it is equalized.

All this results in less CO2 in the liquid. A trick is to squeeze the bottle until there is little to no air in it and then cap it, that keeps the gas in the liquid.

Won't work. CO2 concentration in the liquid phase is a function of pressure (henry's law), and squeezing the bottle won't change the pressure. When the pressure increases inside the bottle, it will simply expand.

It does work. Think it through.

I did. It doesn't, at least not to my understanding of chemistry. I'm more than happy to listen to arguments or data implying otherwise.

no, it doesnt work.

 

[videogames101]

Use vice-grips to close the bottle.

 

[dighn]

Originally posted by: uclaLabrat

Originally posted by: spidey07

Originally posted by: uclaLabrat

Originally posted by: spidey07
No. Since the bottle is bigger there is much more air in the container than before where the CO2 was saturated in solution. The CO2 will move from the lidquid to the now larger volume of air in the container until it is equalized.

All this results in less CO2 in the liquid. A trick is to squeeze the bottle until there is little to no air in it and then cap it, that keeps the gas in the liquid.

Won't work. CO2 concentration in the liquid phase is a function of pressure (henry's law), and squeezing the bottle won't change the pressure. When the pressure increases inside the bottle, it will simply expand.

It does work. Think it through.

I did. It doesn't, at least not to my understanding of chemistry. I'm more than happy to listen to arguments or data implying otherwise.

It depends on how your deform the bottle. If the bottle is deformed in such a way that it actually resists expansion (I think it's possible to do this) then the smaller volume will mean less gas escapes from the pop.

but generally by squeezing the bottle you actually decrease the pressure inside when the bottle tries to maintain the previous shape, so the end result is flatter. or if the deformation does not hold against the gas pressure and expands into full shape anyway, in which case the pop will be flatter again because more CO2 will be used to maintain the pressure (as opposed to having some air in there previously).

 

[sandorski]

Originally posted by: videogames101
Use vice-grips to close the bottle.

Unnecessary. I hate people that tighten as far as they can. It's difficult to undo and totally a waste of energy. It doesn't need to be any tighter than the original seal, which isn't even close to as tight as the cap can be put on.

 

[MrPickins]

You need a fizz keeper.

It's a bottle cap with a pump built in that lets you pressurize the bottle and keeps the CO2 in soln.

Edit: or at least it's supposed to. It can never match the partial pressure of CO2 that the bottle originally had.

 

[Fayd]

Originally posted by: MrPickins
You need a fizz keeper.

It's a bottle cap with a pump built in that lets you pressurize the bottle and keeps the CO2 in soln.

Edit: or at least it's supposed to. It can never match the partial pressure of CO2 that the bottle originally had.

if you read the link you posted, it says essentially that the fizz keeper is a joke. it doesnt help keep fizz by more than a few hours at most.

my opinion is drink soda fast. i go through about a 2L bottle a day of soda, so i dont have to worry about it depressurizing on me.