...a dangerous substance!
I started making some ginger beer a few weeks ago. The red cap bottle is from my first batch which has been maturing since then.
I remembered common stories of explosive beer bottles when I was a child and I noticed that the home brew companies supply PET bottles now. So when I delved into ginger beer again (I tried it about 10 years ago, but the plant never worked) I thought old soft drink bottles would be the way to go.
And they are. The screw cap means that the pressure build up can be let off slowly. For an idea of how much pressure has built up, you can see the bottle in the picture has swollen smooth. Even the (red) cap has bowed out.
I tried a wire top glass bottle (you know, the sort with the overcentre mechanism). But I was getting a bit worried about the glass standing up to the pressure. I opened it over the bath and it went off with a bang. It blew the wire completely off the neck of the bottle and emptied the ginger beer, except for a cm or so in the bottom, virtually instantly.
The taste isn't too bad though!