If you take an un-opened beer and shake it, does the pressure inside increase?
 


















 

Yes. CO2 comes out of solution and occupies the head space in the container.

Yes, but the treadmill has to be set at a 2% incline.

Then what occupies the space when it hasn't been shaken?

Yes. When the CO2 is diffused in the water, the intermolecular forces (mostly hydrogen bonding since beer is almost all water) prevents the gas from behaving like a gas and exerting pressure on its environment. Shaking causes it to concentrate into bubbles which frees it from the solution so the pressure inside the bottle increases. As to why bubbles start from just shaking I forget.....Chem 2 was a long time ago.



 

Gas expands when it comes out of solution.   Expansion in a fixed volume container = increased pressure.   Shaking it encourages this process, which is why soda, beer, etc explodes when you do it.

Kind of like how water expands when it freezes (but has a lower freezing point when salts are dissolved within it):  molecules do funny things depending on the tempurature, pressure and solution.

The container expands.





 

Take an open 2 liter bottle of soda and shake it.  It will go from "soft" to "hard" the same thing happens in a glass bottle.

So, my glass bottle will expand if shaken?

I realize that. The statement made it sound like something else occupied that space. It's not getting displaced it's expanding.

Yes.



 

CO2, of course. But when the can is cold and undisturbed, most of the CO2 dissolves into the beer.

Simple test: go buy a 2L soda from the store and put it in your fridge, get it nice and cold. Take it out carefully and give it a squeeze. Now take it outside and give it a good whack against something hard (don't break it, you fool) or shake the shit out of it. Now try squeezing the bottle again: it should be much more difficult to compress.

Incidentally, this is why soda bottles make good pressure vessels for all sorts of fun home-science experiments: they have to withstand a LOT of pressure during the carbonation process and shipping.

CO2, but at a lower pressure. Most of the CO2 is dissolved in the water.

Carbonated beverages are super saturated with respect to CO2. Meaning they force the water in the beverage to absorb more CO2 then it would like because they do it under pressure. This is why it bubbles off when you open the bottle and let it sit in the open air.

Less pressure.






Yes, but not enough to notice.



Glass is actually a plastic.





 

I will post the answer later. It's locked in a box and I can't find the key.

Yes, but It's a sealed container, so its mass and weight stay the same. Unless you take it from Denver to Baltimore, then the weight will be slightly more, but mass stays the same.

Put a mothball in it, then shake it.

Don't forget that shaking also adds energy.

Some friend you are, trying to ruin this guy's brew!



 

Actually, yes. Glass is a liquid. The expansion is probably not noticeable - probably not measurable in a practical sense.

Read this and tell me what you think:



http://math.ucr.edu/home/baez/physics/General/Glass/glass.html



 

Oh that was very fulfilling to read as a nerd.... I feel naughty now.







 

Gas volume stays the same as more gas molecules (released from the liquid) occupy the non-liquid space.  Thus, pressure increases.  The amount of expansion in the aluminum / glass / kryptonite container is inconsequential.

It only becomes supersaturated once you open it.

Saturation curves are scaled with respect to temperature and pressure.  CO2 gas goes into solution in water at a rate proportional to the partial pressure of CO2 and inversely proportional to the temperature of the water.

In the beer industry, carbonation levels are measured in "volumes" of CO2.  One volume is equivalent to one liter of gas at STP dissolved into one liter of beer.  Atmospheric partial pressure can sustain just above 1 volume.  So true cask beer, which some think of as uncarbonated, is actually just slightly carbonated.  In order to fully degas any fermented beverage, you must boil it (used for testing purposes), run it through a pressure drop (filtration in the case of wine, for example), agitation or some other method.  

Budweiser/Miller/Coors are very heavily carbonated, generally between 2.75 and 3 volumes.  Most craft beer is 2.25-2.5 volumes or so.  Belgians are generally higher that all of them - 3-3.5 volumes - as they are bottle-conditioned to a high degree.  The American style brown 12oz. glass bottle is only rated to 3 volumes or around 12-14psig at room temperature.  Belgians come in 11.2 ounce bottles because they have thicker walls.  In order to fit in the same size 6/4-pack carriers and on shelves, the glass is thicker while the OD is the same - so, less volume.

Shaking a beer degasses it via agitation.  This increases the partial pressure of CO2 inside the headspace until a new equilibrium point is reached.  If allowed to sit and rest for a while, the gas will go back into solution until the original equilibrium point is restored.

That's it? Come on people!

Bump for the answer.