Beer going flat in the fridge - can it be too cold?

[Nztayls]

Okay,

So I have a really good witbier that I have been drinking. The first few bottles I chilled down in the fridge in the house. Opened them up, heaps of carbonation, good head (see attached photo) and very tasty. These were bottled in PET bottles, and you could tell they were well carbonated, as there was absolutely no give in them when you squeezed them

So in my eagerness I threw the majority of whats left into my spare fridge in the basement. This also has a carboy of lager sitting in it at present, and the fridge was down as low as I could possibly get it.

Now the problems start. Every bottle I open has minimal carbonation, bordering on flat. Additionally, the bottles now can be squeezed slightly. 

The bottles not put in the fridge which are still at room temp are still rock solid.

All I can think off is that the extreme cold temp of the fridge has caused the plastic necks of the bottles to contract every so slightly, and this has lead to leaks with the lid. 

I have removed the remaining bottles from the fridge in a hope that when they warm up they will get a bit of life back in them...but it may be too late, and I might have lost the patient. 

Can a fridge be too cold?, can this happen?. This is the only time this has happened to me, and while I am new to this, I have gone through five other batches with no flat beer from the PET bottles before.

[Ralph]

CO2 is much more dissolvable in the liquid as the temperature drops.

If you leave the bottles out somewhere a bit warmer for a day or two do they carb up again?

[Nztayls]

No. I had hoped they would, but they seem to have remained the same. I might try them somewhere warmer perhaps,...leave them in the sun for a couple of days!

[Ralph]

Leaving them in the sun is not really a great idea as UV light can do bad things to how beer tastes... but maybe try sitting them around at room temp for a couple of days. If they are not carbing up it may be that there have been leaks, although that sounds quite strange to me?? 

[Robbo]

that is pornographic. i LOVE IT!

and yes, i would expect that everything would be contracting at a more-or-less, similar rate, so wouldn't expect leaks from that.