A non-carbonated soda tastes horrible. It’s almost as bad as drinking a shake at room temperature. This often happens with soda bottles, so we can always choose to buy single-serving cans or smaller bottles. However, it will always be more expensive than 2 litres.
The problem with two-liter soda bottles is that they go flat quickly. For those with tons of money it’s not a deterrent to get a cap that adds pressure to carbonated beverages by pumping air into the interior which helps prevent dissolved gas from escaping. However, there is another fundamental trick to keep the gas inside once opened.
Keep cold and close properly
Although opting for a special cap will probably work, the science behind it works with much inferior and cheaper methods. For example, experts indicate that the colder the soft drink is, the better it will be preserved. Basically, to keep a gas dissolved in a solution longer, that solution needs to be as cold as possible. That’s why soft drinks are so much harder to swallow when they’re cold.
It is also recommended to close the cap as soon as the soda bottle is opened. It is advisable to pour the drink and replace the cap immediately, turning the cap as hard as possible.
squeeze the air
It may not be the prettiest method, but it definitely works. After pouring a little soda (maybe around 60 percent) from the bottle, we can squeeze the bottle to remove as much air as possible.
This is Henry’s Law , which states that ” at a constant temperature, the amount of a given gas that dissolves in a given type and volume of liquid is directly proportional to the partial pressure of that gas in equilibrium with that liquid ” .
More or less, when we first buy a bottle of soda, the space above the liquid is almost pure carbon dioxide (CO2). So when we open it up, that hiss is the CO2 coming out. If we leave a half-full bottle of soda, the CO2 will leak out much faster because there is less pressure and more space in the liquid (soda).
So squeezing the bottle decreases the space above the solution and increases the amount of pressure inside the container.