Bad bottle? (bottle bomb)

[chthon]

Bad bottles just crack at one point. I had one with a saison, the bottom just came off. Overpriming will make much more of an explosive mess.

 

[Lynx Brewery]

I had three bottles go during the very hot spell that we had at the end of July. My beers are stored on a bench in my garage that gets hot on sunny mornings. I moved them all onto the concrete floor where it’s about 3 or 4 degrees cooler.
I’ve had no problems since until I found this one, this morning.


It’s a Porter that was brewed on 7 May with an OG of 1.056 The SG had dropped to 1.013 on 12 May and stayed the same until I bottled it on 29 May

I batch primed 21 litres with 90g of sugar, aiming for 2.0 volumes of CO2.
I opened another bottle today and it gushed, so overprimed, I guess.

Do you think that the hot weather could have caused it or perhaps not mixing sufficiently when priming. I don’t remember the other bottles that I opened earlier were over-carbonated.

 

[Sandimas]

I had three bottles go during the very hot spell that we had at the end of July.

The temperature in the garage will definitely have has an effect. Garages get much hotter than you expect in summer, I keep a max-min thermometer in mine and am constantly surprised how hot it gets even without a heatwave. And that July heatwave was hot.

I store my brews in the garage but move them indoors during July/Aug, to avoid the extremes of heat. Even then I still get some gushers, thankfully none have gone bang yet this year.

I don't think you have over-primed, the heat has somehow re-activated the yeast. I don't think it's an infection either. I get this every year. I keep telling myself to stop brewing in summer unless I can get all the bottles in the fridge. Batches of hoppy beers brewed around the same time but stored in the fridge 2 weeks after conditioning don't foam. I can't explain the reason the others foam / break (see my other thread on Gushers) but the consistency with which it happens suggests it's to do with storage temperature, it never happens with beer brewed Sept-Apr.

 

[An Ankoù]

I think that bottles can develop weakness from physical mis-use. Twice, I've noticed a puddle of beer on the floor, but couldn't find any glass. It turned out that the bottle had cracked around its circumference and the beer had oozed out without displacing the upper part of the bottle.

A bottle bomb is something else, where a very high pressure builds up inside and the bottle eventually goes off like a grenade. I've never had one of those, thankfully.

 

[Twopan]

This is enlightening. Please see my post in 'gushers again'.

Since posting that, I've had another Newkie Brown clear bottle go off like a grenade. These have been stored in the garage and the posts above suggest it's just too warm for them. I shall have to find a different storage solution in summer

 

[foxbat]

I had three bottles go during the very hot spell that we had at the end of July. My beers are stored on a bench in my garage that gets hot on sunny mornings. I moved them all onto the concrete floor where it’s about 3 or 4 degrees cooler.
I’ve had no problems since until I found this one, this morning.


It’s a Porter that was brewed on 7 May with an OG of 1.056 The SG had dropped to 1.013 on 12 May and stayed the same until I bottled it on 29 May

I batch primed 21 litres with 90g of sugar, aiming for 2.0 volumes of CO2.
I opened another bottle today and it gushed, so overprimed, I guess.

Do you think that the hot weather could have caused it or perhaps not mixing sufficiently when priming. I don’t remember the other bottles that I opened earlier were over-carbonated.View attachment 52680

That's how they're meant to fail under excess pressure - the bottom blows out. If the neck breaks like it did for @Steve_89 then I suspect that it got weakened somehow, maybe due to too much downward pressure from the capper.

 

[DavidDetroit]

I batch primed 21 litres with 90g of sugar, aiming for 2.0 volumes of CO2.
I opened another bottle today and it gushed, so overprimed, I guess.

Do you think that the hot weather could have caused it or perhaps not mixing sufficiently when priming.

Definitely not overprimed, as mentioned.
Based on the info you provided, the batch was finished fermenting before you bottled. And 90g being about 3.2oz for 21 liters is not a lot of sugar.
As far as I am aware, once the yeast has addressed the the sugar in a bottle, it doesn't continue to work endlessly, no matter the temp. If the temp is too high, that's a bad environment for yeast to work, anyway.
I only got gushers one time and that's when I added fruit to the batch and created a variable and some error on my part. I would guess the gushing is caused by another factor--wild yeast or something.

Now, if I am mistaken about my understanding of bottling, I am all ears.

 

[Sandimas]

I would guess the gushing is caused by another factor--wild yeast or something.

I think you're probably right: for me these problems only occur with beers brewed in summer, from May onwards. Something has to produce the additional CO2 and the original yeast is exhaused, so it can only be wild yeast, presumably in the air.

I've got a variety of beers in storage going right back to Jan and it's only the recent ones that are foaming, and the same happens every single year, no matter what I do to try and prevent it. I'm meticulous about sanitation and even use diluted bleach and boiling water because I have had "proper" infections in the past.

For those who have never had this, I think you're lucky. Maybe there's an increased risk because of where I live, out in the countryside?

 

[DavidDetroit]

For those who have never had this, I think you're lucky. Maybe there's an increased risk because of where I live, out in the countryside?

Maybe brewers with the same factors (country and time of year) could provide insight.

 

[moto748]

I've settled now on syringing sugar solution into each bottle as the best way to ensure consistent priming IMO. Then I cap it, invert the bottle to mix in the sugar solution, and leave it to carb. Everyone has their favourite method, but that works for me.

 

[An Ankoù]

While this is probably not relevant to the OP's Cooper's Stout, I just opened Scott Janish' book at random and came across Ch. 9 on hop creep. It would seem that the enzymatic action resulting from dry hopping can carry over into the bottles so that the enzymes in the hops degrade residual dextrins into fermentatble sugars and result in overcarbonation. He reports no fewer than 4 such enzymes in Cascade hops, including amyloglocosidase, alpha and beta amylases and one other. An interesting chapter and well worth a read if you've got the book.