PET pasteurization mishap

[GreyRaven]

I just bottled a batch of hard root beer, let it carbonate overnight until the bottles were rock-hard and then pasteurized them using the dishwasher. I don't think I will be using that method again after seeing the results. I'm thinking this was a combination of leaving the bottles too long in the heat and having too much carbonation pressure to begin with.

The bottle on the right is what they start out as, the one on the left is the deformed bottle.

With some of the bottles showing signs of nearing explosion, I bled some gas out of each of them and resealed them. I'm hoping they will still be tasty and drinkable, but I'm not sure the bottles will be reusable unless I find a way to keep round bottoms upright.

 

[alphaomega]

Might it be that, the plastic was deformed due to being softened by the heat?
I've tried sanitizing a PET bottle with boiling water once and it just shriveled up.
It is not unreasonable to think that the heat made it more pliable and the pressure then took advantage of that