Originally Posted by GrizlyGarou
The liquid can hold more CO2 in solution when it's colder. So it stays in the beer instead of gushing out when the pressure changes when you pop the cap off.
Pretty sure it's the opposite, ie it comes out of the beer before you open the bottle.
When you pop the cap off of a bottle, you drop the pressure instantaneously. This reduces solubility of the gas, allowing it to come out of solution violently. This is similar to how a diver gets the bends if he returns to the surface too quickly.
Cooling a bottle down reduces the pressure inside it, reducing solubility of the gas and allowing some of it to escape into the head space. When the bottle is opened, this portion escapes uneventfully into the surrounding air. Obviously, some additional gas does come out of solution, but since the vapor pressure has been reduced prior to the opening event, the pressure differential is much smaller and therefore the process is much less violent.
Qualifier: I'm a mechanical engineer, not a chemist, and I've only taken three courses in thermo (the most recent of which was 3 years ago).