Green beer drinker - aging beer worry.

Okay, I think cause I have been drinking my beers too green and not really giving them enough time to carb and condition that I'm over compensating with too much priming sugar.

Trouble is I may be going to store them longer and I'm concerned about the bottles.

I have one bottle of my coopers lager in a PET 1 litre bottle (bottled 15 January) and when tapped it rings with a very high note, the bottle can barely be squeezed with a lot of force. The pleats at the bottom are definately showing signs of expanding.

I have reluctantly put it in the fridge. Reluctantly as this places it in the line of fire for drinking. Cold beer is far too much of a temptation.

There are 2 more brews where i have used the same amount of priming sugar per bottle and the latest one (customize coopers draught + grains) bottled very cloudy and the bottle pressure has risen very rapidly in the first few days clearing.

I don't have fridge space to cool more than about 10 litres, 16 maybe if I lay some bottles on their side.

Priming sugar used was fine corn sugar and a large heaped teaspoon per bottle. I haven't checked how much that weighs though, but I suspect it's about 10g per litre maybe 12. This wasn't a 5ml teaspoon.

How worried should I be?

According to How to Brew by John Palmer, you're ideal priming sugar amount when dealing with Corn Sugar would be 114 grams per 18.93 liters or 6 grams per liter. Bumping it up to 10 would could cause excess carbonation depending on the mount of yeast in suspension at the time of transfer to bottles. At least that's my belief, others here, who have been brewing longer than I have, may offer a different opinion. The way I used to carbonate was to use light DME boiled in water and rack onto it in a bottling bucket. Then I'd gently stir with a spoon and let sit for 30 minutes before transferring to the bottles.

Do those bottles have a screw on cap? If they do you may be able to open them just enough to release some of the pressure.
ShinyBuddha has it right you did over prime them a little. In my experience it has always worked been best to add the priming sugar/DME to the bottling bucket if you have one.

No bottling bucket here. I could syphon into another primary... if it's available that is.

I know PET bottles survive a LOT more pressure than glass, but that means if an imperfection in the moulding (and these have visible imperfections!) causes the bottle to fail there will be a lot of pressure to release, spraying beer everywhere.

1 bottle probably won't do much damage to carpet etc. But electrics... another matter. Also the bottle could torpedo into dry stud wall and make a hole.

If I use per bottle priming again, I'll first weigh what I was using to get an accurate measure and then lower it to about 6-8g per bottle.

For the 2 batches I have in bottles, I keep an eye on them and refrigerate until I run out of fridge space, then start drinking quickly, or releasing pressure from them.