We all experience that sparkling water in a closed bottle will degas for a certain time and as the amount of degassed CO2 increases, this process slows down.
My question is: can I slow down the degassing by increasing the pressure in the bottle manually? Do I need (pure) CO2 for that or would it also work when just pumping air inside?
Any pressure on the liquid in the bottle would prevent or slow down the de-gassing, it doesn't necessarily have to be CO2. Divers breath various mixtures when they dive deep, and have to surface very gradually to prevent bubbles forming in their blood. Failure to take this precaution might result in bubbles forming in brain or heart, with severe consequences for the diver. The simplest way to stop excessive fizz in a bottle of pop is to release the pressure very gradually, but if you want to stop it by pumping in a gas, air would do.
