Why does the champagne gush out all over the place when I open the bottle?

If I said that shaking a bottle of champagne, beer or pop raises the gas pressure inside, ninety-nine out of a hundred people, even chemists and physicists, would agree. But it's not true. When you shake an unopened bottle or can of carbonated beverage the pressure inside does not change.Then why does the liquid squirt out with so much force when you open a shaken bottle? It's only because shaking makes it easier for gas to escape from the liquid, and in its eagerness to escape when the bottle is opened it carries some liquid along with it.If an unopened bottle has been standing quietly at room temperature for a day or so and is then shaken, the pressure of carbon dioxide gas in the head space (the space above the liquid) does not change.

The reason is that the gas pressure is determined by only two things: (a) the temperature and (b) how much carbon dioxide can dissolve in the liquid at that temperature.There is only so much carbon dioxide gas in the bottle; some of it is dissolved in the liquid and some of it is loose in the head space. When an unopened bottle of soda has remained at the same temperature for some time, the amount of gas dissolved in the liquid and more important, the amount of gas that is not dissolved in the liquid settles down to whatever the appropriate proportions are for that particular temperature.( The system comes to equilibrium).

The point is that shaking alone can't change the pressure because it doesn't change the temperature or in any other way change the amount of force or energy that is available inside the bottle. So never fear that manhandling your beer, soda or champagne on the way home from the store will make the bottles explode. On the other hand, make sure not to let the bottles heat up in the trunk of your car, because the higher temperature will indeed raise the pressure of the gas.

Now we can take a more educated look at what causes the explosive emission when we open a recently shaken bottle. It is caused by an increase in the amount of gas that is set loose—not by heating, but by the mechanical “outing” of some dissolved carbon dioxide from the liquid when the bottle is opened.

Shaking a bottle or can of beer or soda pop does not increase the pressure inside.

Oh, the champagne? Same thing. The best way to handle it is to leave it undisturbed in the refrigerator long enough for it to “come to equilibrium”—at least twenty-four hours. Then be careful not to either warm or agitate it before or during opening. After removing the wire twist,ease the cork upward with your thumbs. All of the champagne will stay in the bottle and the cork won't become a lethal missile.