Bottle bombs, myth or not .... RESULTS ARE IN

[oldstout]

The bigger the gap the bigger the bang.
When we were kids, we experimented with bottles filled with just one third sugar solution and yeast to which a crown cap was fitted. The big gap meant lots of space for compressed gas and lots of force when the bottle exploded - trust mew, you wouldn't want to be in the same post code.

We did something along those lines with acetylene gas pumped into a black bin liner with a petrol soaked string fuse in a back lane many moons ago.

The bomb squad are still trying to find out where the noise came from without finding any crater whatsoever......... :whistle:



:lol:

 

[PD]

Aa ha twas you !

Now they know.




:lol:

 

[ScottM]

Here's one for you guys....

For some reason my fridge in the garage managed to chill all my brews down past freezing. They were frozen absolutely solid and not one of my bottles have shattered. With 2 of them the lids have given away slightly. I have 2 bottles in the house just now thawing out, as they are doing so the liquid is all the way up to the cap (as the ice takes up more space than the liquid) and they are all perfectly fine.

This absolutely convinces me that any bottle bombs are down to the bottles being defective. The caps give out before the glass does

 

[oldstout]

Here's one for you guys....

For some reason my fridge in the garage managed to chill all my brews down past freezing. They were frozen absolutely solid and not one of my bottles have shattered. With 2 of them the lids have given away slightly. I have 2 bottles in the house just now thawing out, as they are doing so the liquid is all the way up to the cap (as the ice takes up more space than the liquid) and they are all perfectly fine.

This absolutely convinces me that any bottle bombs are down to the bottles being defective. The caps give out before the glass does

:thumb:

 

[Davybarman]

This absolutely convinces me that any bottle bombs are down to the bottles being defective. The caps give out before the glass does

Scott Have to agree with you.

One batch I did, I made the newbie mistake of bottling to soon and probably overpriming too. Anyway one big heat wave and the bottles that exploded were the older commercial beer bottles that were recycled. Also for some reason the majority were clear as well!! :wha:

Anyhow wont make that mistake again!! :whistle:

 

[BarnsleyBrewer]

This absolutely convinces me that any bottle bombs are down to the bottles being defective. The caps give out before the glass does

Scott Have to agree with you.

Sorry but I disagree, It's probably the expanding ice that shoves the top off slowly and not the pressure inside....
Bottle bombs should never be a problem for experienced brewers, especially using dried yeast.. The only problem I ever had with exploding bottles was with proper brewers yeast that just kept nibbling away at any sugars it could find in the bottle...
BB

 

[ScottM]

This absolutely convinces me that any bottle bombs are down to the bottles being defective. The caps give out before the glass does

Scott Have to agree with you.

Sorry but I disagree, It's probably the expanding ice that shoves the top off slowly and not the pressure inside....
Bottle bombs should never be a problem for experienced brewers, especially using dried yeast.. The only problem I ever had with exploding bottles was with proper brewers yeast that just kept nibbling away at any sugars it could find in the bottle...
BB

I don't see how you can disagree. I bottled my beer with 1.5" of headspace. They sat in my house for a week carbonating. When they went into the garage they started to freeze. The headspace is already pressurised due to the carbonating and during this freezing process the liquid became a solid thus expanding and pressurising the bottle further by using up said headspace. The 1.5" at the top of the bottle was less than 1/8", the pressure of which pushed the lid off a little and relieved.

You can not believe me if you choose, but if you believe what I am saying to be true then it's irrefutable. The pressure created by liquid turning to ice and expanding is 10000s of PSI, ice can shatter an engine block like a toothpick (not enough antifreeze) so it would have absolutely no problems in shattering a piddly beer bottle if the pressure wasn't released somewhere.

I'll assess the damage today but as far as I could see yesterday 3 bottles had leaked slightly, the rest are fine. There is WAY more pressure created in these circumstances than there ever will be by yeast.

 

[alanywiseman.]

I dont think it is quite so simple Scott. As you cool a solution you increase the solubility of CO2 therefore reducing the pressure in the head space. This would mean as the liquid freezes the increase in pressure is not linear.

I think defects are the reason for most bottle bombs and can probably be detected by the way the bottle breaks (most of it stays in one peice). When a bottle truely explodes and shatteres this is not due to a defect but just too much pressure. So why didnt your shatter?

As the ice formed and stated to touch the cap, due to the non-uniform formation od the ice the caps would have been warped, weaking the seal meaning the seal got boken and any pressure build up was relieved.

 

[ScottM]

I dont think it is quite so simple Scott. As you cool a solution you increase the solubility of CO2 therefore reducing the pressure in the head space. This would mean as the liquid freezes the increase in pressure is not linear.

I think defects are the reason for most bottle bombs and can probably be detected by the way the bottle breaks (most of it stays in one peice). When a bottle truely explodes and shatteres this is not due to a defect but just too much pressure. So why didnt your shatter?

As the ice formed and stated to touch the cap, due to the non-uniform formation od the ice the caps would have been warped, weaking the seal meaning the seal got boken and any pressure build up was relieved.

They didn't touch the cap though, they got close to it as they were de-frosting and the liquid made its way up there. It was the pressure that opened the cap, not any physical presence of the ice. The solid ones I looked at had about 1/2" of headspace left while they were rock solid. It was as they were freezing that the pressure built up and pushed the cap open. Evidence of this is the frozen liquid that the bottles were sitting in, it had leaked down the side.

I would surmise that as the bottle froze the remaining liquid pressurised the bottle rather than the gas. The buildup of pressure popped the cap a tiny amount and relieved it, thus the slight spillage. This allowed the remaining liquid to freeze without anymore pressure buildup, hence why the bottles aren't in bits.

If the bottle was the weak point then the pressure buildup would have broken the bottle, rather than popped the lid. The cap, in my bottles at least, is the weak point.

 

[Earpworm]

It doesn't help answer the question one bit but there is a great scene in Breaking Bad season 2 ep5 featuring bottle bombs.
A great series with really dark humour.

Schraderbrau

 

[johnnie]

Why don't we take this a step further? My next brew day is 30/8/12 when I get back from hols. My garage has a concrete floor and I've got a few concrete blocks around to build a wall around the bottles. The garage heats up during the day. I might draw off a few bottles from the fv (before its finished fermenting) to see what happens. My only concern is that they might go off while i'm taking a peek.

 

[ScottM]

Why don't we take this a step further? My next brew day is 30/8/12 when I get back from hols. My garage has a concrete floor and I've got a few concrete blocks around to build a wall around the bottles. The garage heats up during the day. I might draw off a few bottles from the fv (before its finished fermenting) to see what happens. My only concern is that they might go off while i'm taking a peek.

I wouldn't worry about it too much, I say go for it

If you want to be sure a small piece of perspex would do nicely :)

 

[pittsy]

for those that think bottle bombs are a myth , and wish to try it out well you will see the hard way that it ain't no myth , once you have a full batch that starts exploding left , right and center with pieces of glass cutting into your arms while you try to open the remaining bottles (i was wearing safety glasses and had to open them as they were in my spare room , upstairs) . In total 6 bottles exploded and 30 bottles were saved but all of the brew foamed out of em , this was down to a school boy error when using candy sugar to prime , in effect i doubled the dose of a high carb amount so in real terms it was around 250/300g of sugar (poss). There was different bottles that exploded , new and old .

 

[ScottM]

for those that think bottle bombs are a myth , and wish to try it out well you will see the hard way that it ain't no myth , once you have a full batch that starts exploding left , right and center with pieces of glass cutting into your arms while you try to open the remaining bottles (i was wearing safety glasses and had to open them as they were in my spare room , upstairs) . In total 6 bottles exploded and 30 bottles were saved but all of the brew foamed out of em , this was down to a school boy error when using candy sugar to prime , in effect i doubled the dose of a high carb amount so in real terms it was around 250/300g of sugar (poss). There was different bottles that exploded , new and old .

If I used those bottles I would have a fridge full of glass and ice by now. My first lager was brewed with 250g of sugar with no ill effects other than a pint of head

 

[ScottM]

Just googled this out of curiosity.

Beer bottles are made to hold between 50 and 100psi, differs from manufacturer to manufacturer. Bottle conditioning at a rate of 8g per litre is the equivalent of around 13psi and is what most beers are brewed to (2 volumes of CO2).

You would need to be well over the sugar ratio and have the brew at a fairly high temperature to even be reaching the recommended safe limit. I'm only guessing here but given most manufacturers factors of safety, them assuring 50PSI would basically mean 100PSI would probably be fine.

Hitting anywhere near those levels would surely see the yeast stop in its tracks before making something pop?

 

[TRXnMe]

As yet I don't k ow a lot about brewing, but I do know a truck load about broken glass and the physics of breaking glass, I was a Process Engineer responsible for making TV tubes for a major Japanese manufacturer, those things get heated and cooled, then they have close to a total vacuum pulled on them, while being heated, the stresses are 'interesting' (I'm an Engineer, so interesting to folk like me anyway).

With all that ^ in my head, my money is on flaws in the glass allowing them to fail being the primary cause for bottle bombs, the math for pressure has been done above, along with the capability of the standard beer bottles to withstand pressure.

You only need one to go, it will scratch others in the area, the scratches act as stress concentrators and allow the scratched bottle to fail, resulting in sequential failure. I've seen instances of 20 to 30 TV tubes going bang, because one of them blew and took out the rest.

 

[Ken L]

Perhaps the doubters should take half a bottle of half fermented must, crown cap it and leave it in a safe place under a cardboard box for a couple of weeks.
If it somehow fails to go though, don't even think about opening it without heavy leather gloves and a full face guard.

 

[ScottM]

As yet I don't k ow a lot about brewing, but I do know a truck load about broken glass and the physics of breaking glass, I was a Process Engineer responsible for making TV tubes for a major Japanese manufacturer, those things get heated and cooled, then they have close to a total vacuum pulled on them, while being heated, the stresses are 'interesting' (I'm an Engineer, so interesting to folk like me anyway).

With all that ^ in my head, my money is on flaws in the glass allowing them to fail being the primary cause for bottle bombs, the math for pressure has been done above, along with the capability of the standard beer bottles to withstand pressure.

You only need one to go, it will scratch others in the area, the scratches act as stress concentrators and allow the scratched bottle to fail, resulting in sequential failure. I've seen instances of 20 to 30 TV tubes going bang, because one of them blew and took out the rest.

Good point on the chain reaction :thumb:

 

[Baz Chaz]

Perhaps the doubters should take half a bottle of half fermented must, crown cap it and leave it in a safe place under a cardboard box for a couple of weeks.

When the weather warms up, I think this 'experiment' might just have a re-run :grin:

I'll scrounge a couple of old tyres from the garage with a weighted wooden lid* this becomes a pretty safe store for anything that may go boom (in the bottle bomb way anyway) under the greenhouse bench and see what happens :whistle:

There used to be a Heath Robinson set up like this at a number of our local Police Stations years ago, people we forever finding mortars in the area, often had someone at the front office turn up with one :?

 

[calumscott]

I say go for it. And leave them longer too.

Give them a good three weeks or more at fermentation temp and just leave them alone in the "bomb hole" for a month or so...

Also, if you are willing to sacrifice beer, have a good root through your bottle stash for one that looks a little less than perfect, one that's lived a little... :lol:

Maybe some lesser quality bottles too? Lightweight mass produced beer bottles maybe?

I still reckon that you'll struggle to get a decent, unmolested, designed for proper beer bottle to go bang all on its own. Maybe a 16g prime, some agitation and a temperature increase might just get you "over the line"...?