Help Diagnosing Cause Of Bottle Bombs

[Jamz]

I've had two bottle bombs across two different batches where I've put a couple beers into crown seal stubbies as well as longnecks. Both times its been this particular brand of stubbie that exploeded on me. After this second time I certianly won't be using those bottles again, but I'd like to work out why they blew up on me.

First time I had one blow up it was my third ever brew, I'd primed the 330ml stubbie with a third of a teaspoon of sugar. FG had been stable over several days, although the FG was a little high there was a lot of non-fermantables in the brew and advice I got on here was that it was probably ready to bottle. I should note that all the longnecks from that batch which were primed with 2/3 of a teaspoon of sugar were all ridiculously undercarbed. When the stubbie blow up on me, it was a 35 degree day if that could have had anything to do with it?

I had a stubbie of a stout that i'd bottled last week do the same thing today. Not a very warm day tho, probably around 20 degrees where I am at the moment. It was a 3kg ESB stout kit and I was expecting an FG around 1.016, it stopped at 1.018 and didn't move after half a week of being kept around 20-21 degrees. Due to the warm weather, at no point would this batch have dropped below about 18 degrees so I think it unlikely that I'd have had a stuck fermentation. So I bulk primed the 18L batch with 90g of dextrose, all the dextrose was properly dissolved placed in the bottling bucket and i had a bit of a whirlpool going as i racked the stout into it. I opened the other two stubbies of stout that I'd bottled and throw the bottles in the garbage, took an hydrometer reading of 1.016 and carbonation seemed pretty much normal. I had a good smell of the mess all over my room and there was no obvious indication of infection.

Since it was the same brand of bottle each time (and not one that I usually use) I'm expecting they played a big part in the problem each time, but I'm a little concerned nonetheless. Can anyone suggest where I may be going wrong?

 

[Quintrex]

As it gets warmer carbon dioxide is a lot less soluble in liquids ie beer and as such wants to expand into it's gaseous state, so basically if your bottles are ever going to explode its going to happen on a hot day. Just find somewhere cooler to keep it if possible.
And steer away from using those bottles
Q

 

[Crunched]

I can't really help you with pointing out what you did wrong, but I will add my 2 cents on bottling: I'm so glad I've moved to kegs. Just now I was working in the garage when the cupboard I keep my bottles in let out a huge BANG! Scared the crap outta me. Taking a look - it was a brew that I had probably over-primed slightly, so definately my fault. 45 minutes of cleaning up later I began to load the bottles into my keg fridge (they've been in the cupboard about a month now). Problem now is, my keg fridge is full of these bottles (which aren't particularly tasty) and my garage stinks of beer (which isn't necessarily a bad thing). My point: No such problems with kegging. No bombs, no over-under carbing (that can't be controlled) and no storage problems (having to find all the space the bottles take up).

 

[Pollux]

Can I ask the brand of bottles used?

I use a few different brand ex-commercial stubbies for mine and I'm wondering if you are using some of the same as me.....

 

[Jamz]

They were just a couple bottles left lying around at my place by one of my mates. I scrubbed the labels off and I can't remember what they said on them. But from memory it was a Spanish beer and they had red labels.

 

[Daniel.lear]

Jamz,

I too would be steering clear of those bottles, When i was bottling ive carbed up too 200g of sugar per 20lts and no probs (carbonation sugars dependant on temp and style of beer).

Leary

 

[raven19]

I have found clean bottles and cool inside temperatures leads to zero issues thus far.
I did store some in the shed - hot week of 38 plus, and most went boom...!

Recommend clean bottles, bulk priming sugar sounds fine - I use usually around 130 - 160 gram for 23L batches.