How does a soft drink lose carbonation?

Answer 1

The carbonation in Carbonated Beverages comes from a gas that is held inside the liquid under pressure while the container is sealed. Once the container is opened, the gas starts to leave the liquid which is what makes it fizzy. Once the gas is all gone, the beverage is no longer carbonated.

Answer 2

One answer was given:

Sugar is added to the mixture and trapped in the closed bottle, which previously had yeast and the initial sugar working in the bottle for at least 24 hours. The yeast works on eating the sugar and gives off carbon dioxide gas, which explains the fizz.

But that is the explanation of the fizz in a variety of Alcoholic Beverages. The carbon dioxide [CO2] in soda pop is created differently. The CO2 dissolved in pop creates a weak carbonic acid (or is it carbolic?). Water readily becomes acidic in the presence of CO2 (this is what causes the sharp sting when burping through your nose after drinking soda pop--the moisture in you nasal passage becomes momentarily acidic).

There is a mechanical device that maximizes the contact between water and CO2 from a gas cylinder as soda pop is being made at the factory, or at the soda head at a restaurant. At the factory the result is then quickly sealed to keep it from going flat; at the restaurant you drink it quickly, before it goes flat.

So water is brought into close contact with CO2, then the result is mixed with flavoring syrup, and the result is soda pop.

Answer 3

Any soft drink can lose its carbonation if left out in a glass at room temperature for about an hour or two hours, as the soft drink goes flat.