If you s***w on the soda cap really tight, will it stay fizzy longer?

Question

Guys always twist the cap super tight, so its really hard to open next time. Some claim this prevents escape of the CO2 to keep it from going "flat". Any truth to this?

Answer 1

On plastic bottles I find if you squeeze the bottle slightly then put the cap on you create a vacuum that keeps the fizz longer

Answer 2

yea!!!! i think so cuz the carbination dosnt escape as much!

Answer 3

I would doubt it, as long as it air tight then I don't think anything would escape but I'm no scientist.

Answer 4

Yes and no.

Gas diffusion through materials is very slow, especially in plastics and metals, however if you leave the cap lightly screwed on, the least strongest point of pressure for the gas to escape is through the cap and the seal against the bottle neck/cap.  Excessive tightening doesn't actually make any difference except if you are shaking the bottle to release all the gas, and even then, finger tight is enough to keep the pressure and gas in.

Quite frankly, if you're going to be opening and closing it to drink it slowly, you'll degass it faster than if you let the cap sit on it closed lightly (but it's still water-tight closed) than tightening it heaps.