Bottles exploding

[Abundant1]

Hey there- I have been brewing for a year now and have been using the 745ml swap a crate bottles. I had 1 exploded yesterday after accidentally knocking it. Anyone out there knows what to do to prevent this from happening? I am not keen on PET bottles.

[MrC]

Hi, unfortunately I have some experience with exploding (cracking) bottles. Even had a PET burst on me once. I haven't had any problems for a few years now due to some good practice, and a good understanding of the available fermentable sugars at bottling time.

In my experience there are three potential causes of over carbonation:

1 - Infection. Years ago (as a student) I had a couple of dodgy bottles that I hadn't cleaned properly and the bacteria was growing in the bottom of the bottle. The beer was overcarbonated and although the bottle didn't explode I could see that the potential was there.

2 - Incomplete fermentation. If fermentation hasn't completed by bottling time, fermentable sugars will remain in the beer and fermentation will therefore continue in the bottle. The main reasons for incomplete fermentation are poor yeast (either purchased bad yeast or poor handling), not enough yeast, not enough time in the fermenter(s), temperatures outside of the yeast's tolerable temp range resulting in poor yeast health. Do you use a hydrometer to check fermentation progress?

3 - Over Priming (or inconsistent primimg). If fermentation is complete and the bottles are clean and sterile, that leaves priming. I would recommend bulk priming over individual bottle priming. Here's a link to HowToBrew on bulk priming. Bulk priming will create a consistent carbonation for all of your bottles and will reduce the chance of accidentally over priming the odd bottle. Have you ever looked at the different sized carbonation drops in a bag, they can't all be right.


I also believe that you can get the odd dodgy bottle. Maybe it has been knocked or heated/cooled too quickly resulting in weakening ofthe bottle. It's virtually impossible to determine dodgy bottles visually (unless it's really obvious) so your best bet it look after your bottles and change them reasonably frequently if you can.

Even now I store my bottles ina place where a "leak" won't matter. I haven't had any problems for years now and I believe that getting in control of the sugars is the key.

Hope that helps.

How do you prime?
What yeast(s) do you use?

[Stu McKinlay]

Mr C has given a pretty thorough account of potential issues.
However... Could well just be an old bottle, if you knocked it. I once had one "explode" on me while bottling. There was no issue with carbonation - the beer was flat! Are you finding your beer is overcarbonated?

[David Falconer]

Mr Cherry has given a really good advice
What you can do now is open a few and if they gush and the beer is not infected you may want to empty the bottles back into the fermenter and let it ferment out and look at bulk priming.
It may also be the result of a low temperature fermentation which was not complete when you bottled, hopefully this should not be such an issue now with warmer weather.
In future you want to check for the end of fermentation with a hydrometer if you do not already do this
Cheers

[Abundant1]

Thank you guys, that's really helpful.