▁the ▁" f izz " ▁is ▁actually ▁returned ▁( since ▁the ▁amount ▁of ▁additional ▁CO 2 ▁that ▁dissol ves ▁once ▁more ▁is ▁several ▁orders ▁of ▁magnitude ▁lower ▁than ▁the ▁amount ▁that ▁caused ▁visible ▁gas ▁b ub bles ▁to ▁form ▁when ▁first ▁esc aping ▁the ▁solution ). ▁ ▁It ▁takes ▁time ▁for ▁the ▁dissol ved ▁CO 2 ▁to ▁come ▁out ▁of ▁solution , ▁in ▁the ▁form ▁of ▁gas ▁b ub bles ▁that ▁grow ▁and ▁b ubble ▁up ▁within ▁the ▁liquid . ▁ ▁Thus ▁if ▁the ▁cap ▁is ▁replaced ▁quickly ▁after ▁opening , ▁an ▁intermediate ▁equilibrium ▁state ▁can ▁be ▁maintained , ▁with ▁CO 2 ▁previously ▁dissol ved ▁in ▁the ▁liquid ▁instead ▁occup ying ▁the ▁head space . ▁ ▁However , ▁the ▁CO 2 ▁partial ▁pressure ▁only ▁ever ▁decre ases ▁on ▁each ▁opening , ▁as ▁more ▁of ▁the ▁gas ▁esc apes ▁from ▁the ▁bott le ▁entirely . ▁ ▁The ▁F izz ▁K ee per ▁does ▁not ▁cause ▁that ▁partial ▁pressure ▁to ▁increase ▁significantly . ▁ ▁Ro hr ig ▁also ▁obser ves ▁from ▁experiment ▁that ▁the ▁F izz ▁K ee per ▁forms ▁a ▁poor er ▁se al ▁than ▁the ▁bott le ' s ▁own ▁sc rew ▁cap , ▁thus ▁allowing ▁CO 2 ▁to ▁leak ▁out , ▁and ▁the ▁CO 2 ▁partial ▁pressure ▁to ▁decrease , ▁more ▁quickly ▁with ▁the ▁F izz ▁K ee per ▁on ▁a ▁bott le ▁than ▁with ▁the ▁normal ▁cap . ▁ ▁Although ▁re - press ur izing ▁the ▁bott le ▁with ▁an ▁ordinary ▁atmos pher ic ▁mixture ▁of ▁g ases ▁does ▁not ▁affect