Summary Man said:What's the best way to keep a 2-liter bottle of soda carbonated longer? Leaving it open while I'm drinking it or capping it, then reopening it every time I'd like to pour myself a drink?
After you've opened it and drank some, squeeze the bottle so that the bottle is indented and the soda goes all the way up to the top, then cap it real tight. With nowhere to go the fizziness shall be retained longer!