I was recently told that twisting off the bottle cap off a soda bottle slowly will make the soda stay carbonated longer.

Conversely, if I opened the cap off in one quick motion, it would get flat quickly.

enter image description here

Is this true?

  • 3
    Releasing the pressure slowly approximates a Joule--Thomson expansion, which is close to a reversible (adiabatic) process that a sudden release. I don't know if this will preserves the carbonation or not, but it sure helps to prevent the stuff foaming over. Sep 20, 2011 at 17:28
  • Huh, I'd always been told the opposite -- opening it slowly allows the carbonation to be released from the soda more quickly. Something about the longer time to equalize the air pressure somehow "sucking" the carbonation out of the liquid. So I'm curious as to what answers this question may bring...
    – Kromey
    Sep 20, 2011 at 22:35
  • 3
    I suggest extensive testing - please video the results :-)
    – Rory Alsop
    Sep 21, 2011 at 10:34
  • I doubt the speed or releasing the pressure will have any effect on the delta percentage of carbonation loss. But I would expect that releasing it slowly would preserve more carbonation in the soda immediately after opening so the end percentage of the slowly released cap should be higher than the end percentage of the fast released cap.
    – Chad
    Sep 21, 2011 at 16:24
  • Time for Mythbusters! If you drop it on the ground several times then open it quickly it will definitely go flat fast.
    – Moab
    Sep 25, 2011 at 5:44


You must log in to answer this question.

Browse other questions tagged .