Explosion in the Man Cave!

Will made some ginger beer last week and bottled it in plastic bottles because, and I quote "they will not explode."He put the 6 filled bottles in a corner of the man cave annex to mature.Sweeping out the man cave this morning I noticed one had fallen over and tried to stand it up but found that it's usual flat bottom was quite rounded. I stood it up as best as I could, leaning on some of the other bottles, and turned away when suddenly there was a loud bang!The bottle had exploded. It sent another bottle flying about 10 feet and sprayed ginger beer all over the annex.I spent a happy(...not)! hour cleaning up the mess! Despite my efforts the place smells more like a man cave than before...slightly 'beery'.I have released the pressure in the other bottles and removed them to a more remote part of the garage.

Plastic bottles do not explode apparently.