On Sat, 17 May 2014 18:03:21 -0400, Dave Smith
> wrote:

>On 2014-05-17 12:45 PM, Gary wrote:
>> Brooklyn1 wrote:
>>>
>>> Two liter Coke keeps well carbonated for me in the fridge for three
>>> days... trick is to squeeze out the air before capping.
>>
>> Very wrong, my friend. Trick is to keep all the air in before capping.
>> If you squeeze it all out, the carbonation in the soda will leek out
>> to fill the container.
>>
>> I drink a 2-liter diet rootbeer once a week at work. The carbonation
>> only lasts a day or two but the rest of the week, I still like the
>> flavor even though it has gone flat.
>>
>
>My late BiL was an engineer and he espoused the squeezing out idea. I
>never understood that. It takes little pressure to push the bottle back
>into shape, so the carbonation can easily escape. If the bottle is
>intact there is slightly more pressure to overcome. We once had a
>gadget that was supposed to seal the bottle and you could pump pressure
>into it. It worked great.... in theory.
>
>I rarely buy large containers of soft drinks. I realize that it is a lot
>cheaper to buy them that way, but I just don't drink enough of that
>stuff to make it worth while. I have 2-3 cans of pop per month so I just
>get 12 packs and each one last months.

It's really quite simple, if the plastic bottle is squeezed so that
there is little to no head room above the liquid then there is nowhere
for the carbonation to go so it stays in the liquid. When one leaves
a large airspace above the liquid it's about the same as leaving the
cap off. Carbonation dissolves into that air space about the same as
it does into the atmosphere... and as the soda is consumed that air
space/atmosphere enlarges. When the plastic bottle is squeezed so
that the air space above the liquid is kept to a minimum it's almost
the same as though the bottle cap was never removed. I don't see
what's so difficult to comprehend.