How do fizzy drinks work??
Discussion
Carrera2 said:
And more importantly why do they go wild when you shake them or pour them quickly into a glass?
Presumabley the liquid has the gas dissolved in it by why does the gas try to escape
The can/bottle is pressurised, which keeps the gas dissolved in the liquid. Opening the bottle releases the pressure and means that the liquid can hold less dissolved gas, so it expands and "fizzes". Letting the pressure go quickly all at once means that bubbles of gas form and try to rise to the surface, pushing the intervening up out of the way, all over your desk, keyboard and trousers...
pdV6 said:
And more importantly why do they go wild when you shake them or pour them quickly into a glass?
Presumabley the liquid has the gas dissolved in it by why does the gas try to escape
The can/bottle is pressurised, which keeps the gas dissolved in the liquid. Opening the bottle releases the pressure and means that the liquid can hold less dissolved gas, so it expands and "fizzes". Letting the pressure go quickly all at once means that bubbles of gas form and try to rise to the surface, pushing the intervening up out of the way, all over your desk, keyboard and trousers...
Got that.
Why does the shaking affect it?
Plotloss said:
There speaks someone who's never owned a soda stream.
Get busy with the fizzy mate...
A few years ago I did some home brew.On pouring it looked pretty flat so I had a "good" idea...stick it in the soda stream....not such a good idea when you get half a pint of beer shooting out of the top of the bottle onto the ceiling and down the cupboards.Won't do that again.
Google comes up trumps again!
Looks like it's all about nucleation.
Small bubbles caused by shaking help to hasten the escape of the soda's carbon dioxide. Cans of carbonated soft drinks contain carbon dioxide under pressure so that the gas dissolves in the liquid drink. Once the the can is opened, all of the gas will eventually escape from the liquid as bubbles, and the soda will go "flat." If the liquid is handled gently, it takes a long time for the dissolved gas to escape. If the can is shaken, however, or if the liquid is poured quickly into a glass, then the bubbles formed by turbulence provide an easier way for the dissolved gas to escape.
It's difficult for the gas to escape from an undisturbed liquid because of the liquid's surface tension, which is the energy required to separate the liquid molecules from one another as a bubble forms. For a tiny bubble just getting started, the amount of energy required per molecule of gas in the bubble is relatively large. So getting started is the difficult stage. Once it is formed, however, a smaller amount of energy (again on a per molecule basis) is needed for additional liquid molecules to vaporize and expand the bubble. The basic reason for this dependence on bubble size is that whereas the volume of the bubble is proportional to the number of molecules inside (at constant pressure), the surface area of the bubble is proportional to the number of molecules to the 2/3 power.
Because shaking the can introduces lots of small bubbles into the liquid, the dissolved gas can more easily vaporize by joining existing bubbles rather than forming new ones. By avoiding the difficult step of bubble formation, the gas can escape more quickly from shaken soda, thus resulting in more fizz.
Looks like it's all about nucleation.
Small bubbles caused by shaking help to hasten the escape of the soda's carbon dioxide. Cans of carbonated soft drinks contain carbon dioxide under pressure so that the gas dissolves in the liquid drink. Once the the can is opened, all of the gas will eventually escape from the liquid as bubbles, and the soda will go "flat." If the liquid is handled gently, it takes a long time for the dissolved gas to escape. If the can is shaken, however, or if the liquid is poured quickly into a glass, then the bubbles formed by turbulence provide an easier way for the dissolved gas to escape.
It's difficult for the gas to escape from an undisturbed liquid because of the liquid's surface tension, which is the energy required to separate the liquid molecules from one another as a bubble forms. For a tiny bubble just getting started, the amount of energy required per molecule of gas in the bubble is relatively large. So getting started is the difficult stage. Once it is formed, however, a smaller amount of energy (again on a per molecule basis) is needed for additional liquid molecules to vaporize and expand the bubble. The basic reason for this dependence on bubble size is that whereas the volume of the bubble is proportional to the number of molecules inside (at constant pressure), the surface area of the bubble is proportional to the number of molecules to the 2/3 power.
Because shaking the can introduces lots of small bubbles into the liquid, the dissolved gas can more easily vaporize by joining existing bubbles rather than forming new ones. By avoiding the difficult step of bubble formation, the gas can escape more quickly from shaken soda, thus resulting in more fizz.
Bubbles in fizzy drinks require a nucleation site, which is why if you have a shape etched in the bottom of a beer glass, you will get a pattern of bubbles in the head of the beer.
Thank god I'm going back to school tomorrow, you people are getting the brunt of my teaching withdrawal!
Thank god I'm going back to school tomorrow, you people are getting the brunt of my teaching withdrawal!
But no-one has yet explained why the drinks companies place CO2 in the drinks to make them fizzy...
It so that the bubbles explode on your tongue, heightening the sense of taste
Or maybe CO2 is cheaper then flavour, so they can weaken the flavour
I used to work for Coca-Cola, and visiting a factory is truly mind boggling, they make 20,000 cans per hour on one line! The can factory is next door, and they shoot the cans across in air tunnels, much like some shops shoot money around in plastic bullets
It so that the bubbles explode on your tongue, heightening the sense of taste
Or maybe CO2 is cheaper then flavour, so they can weaken the flavour
I used to work for Coca-Cola, and visiting a factory is truly mind boggling, they make 20,000 cans per hour on one line! The can factory is next door, and they shoot the cans across in air tunnels, much like some shops shoot money around in plastic bullets
puggit said:
I used to work for Coca-Cola, and visiting a factory is truly mind boggling, they make 20,000 cans per hour on one line! The can factory is next door, and they shoot the cans across in air tunnels, much like some shops shoot money around in plastic bullets
Having visions of Willy Wonka's factory here
It’s been aloooong time since I did Chemistry, but I thought this was down to the carbonic acid which is unstable when water is present. Given that the Carbonic acid breaks down to Carbon dioxide and water – the results are a chain reaction. Well that explains where the bubbles come from anyway ;o)
Gassing Station | The Pie & Piston Archive | Top of Page | What's New | My Stuff