I like to occasionally, but not regularly, have a carbonated drink such as soda water. Buying these in small containers is more expensive and uses more packaging. Big containers go flat before I have finished them. How can I keep my carbonated drinks from going flat for as long as possible?


Transfer the contents of the large bottle to several smaller bottles.

Fizzy drinks go flat because each time they are opened & re-closed, the gas is released from the liquid until parity pressure is reached in the container, preventing any more from escaping.

Once you've reached about the halfway point in any size bottle, you're on a losing run from thereon in. Every time you release the pressure, whether you drink or not, you have a lot of gas to release from the liquid to reattain parity pressure.

If you continue to re-use the smaller bottles, the planet will send you a big green hug too ;-)

  • You're going to lose some carbonation when you transfer the contents ... but if you're going to do this, I'd recommend using glass bottles, as plastic is more permeable. (it's why bottled sodas have such a short shelf life, especially in warmer weather).
    – Joe
    May 20 '20 at 19:26
  • What do you consider a "short" shelf life? Looking at bottles I have here right now, the shortest still has 6 months.
    – unlisted
    May 20 '20 at 19:30
  • I consider 6 months to be short, but you might even less out of it if it's stored in a warm area. Soda in aluminum cans or glass bottles are generally fine after a year of storage (I've never done testing to figure out a more specific time)
    – Joe
    May 20 '20 at 19:35
  • I wonder if squeezing the air out of the bottles (provided they aren't glass, of course) before closing them will have any effect... Anyone have any experience with this?
    – LSchoon
    May 21 '20 at 7:54
  • That would lower the pressure inside, making more gas needing to be released before equilibrium was reached. One thing I didn't note in the answer is that once it's opened, whether it goes flat or not, decanted or not, you're probably down to 1 or 2 week's remaining shelf-life, stored in the fridge, whatever the initial use-by date.
    – unlisted
    May 21 '20 at 7:59

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