Exploding plastic bottles

[Shade]

I've been bottling in plastic since I started, 9 or 10 batches now, and I am suffering a bit of equipment failure.

I keep my beer in the garage to condition which is a pretty even temperature of around 20C (68F). I had no issue for my first 6 batches or so but of late I've had bottles rupture - the other day I found a bottle on the floor of the garage with a hole blown out of the bottom, which had started inside a cardboard box on a shelf nearby, so I imagine it was quite a sight when it happens.

I also cracked a beer last night that had been in the fridge for a day, and it started pumping fizz out of the top and pretty much emptied the whole bottle.

I use carbonation drops and use the same 2 per bottle I have always used, but now I see to be getting a lot more fizz than I used to. Any ideas why?

And is there a point which plastic bottles need replacing?

 

[Gavin C]

Any ideas why?

You bottled before fermentation was complete. This is the most probable cause. (Highly likely given what you describe)

Less likely but possible causes are

• An infection at bottling
• Addition of too much priming sugar

 

[Shade]

Well, that's embarrassing if that's it!

I use the same carbonation drops in the same quantities for all my batches so far so it isn't that.

Thanks, will have to be more diligent with my FG readings.