bottom of bottle popped clean off

[james_cornell]

so I brought some beers into work today to share with coworkers. I ride my bike in and they were in my bag on my back which means they do get pretty shaken up on the ride in. When I got to work, I was transferring them out of the bag into a drawer and the bottom of a bottle just popped clean off. I've never had bottles explode before and this wasn't extremely loud like a gunshot as other people have described exploding bottles.

I sanitize my bottles in a 350 degree oven for 1 hr. These were bottled maybe two weeks ago, stored in a rather dark area of my apartment that tends to sit between 65-70 degrees.

I know there are a few common issues that could lead to a single bottle bomb in a batch: sudden spike in temp, infected bottle, uneven distribution of priming sugar.

Looking at it carefully, the bottom came clean off, not a lot of little shards and not an exploded bottle. The little depression that my bottle capper usually leaves in a cap is still there (I don't know if this means anything but I would assume if the pressure was too much this would have popped up first). Based on this I am assuming that none of the common issues listed above were the reason and nothing I've read has lead me to believe that shaking the bottles on the ride in would cause them to explode. I am assuming that this was a bad bottle either thin or damaged somewhere along the line and it just broke when I put it in the drawer (it sounded like I hit the side of the drawer but that could have just been the bottom popping off).

Does this sound fair or is there something else I should be concerned about, and can agitating a bottle cause it to explode?

 

[orangehero]

You should stop sanitizing in a 350° oven.

 

[james_cornell]

Does that weaken the glass?

 

[orangehero]

Of course, especially if not done with very gradual temperature changes.

 

[day_trippr]

As alluded above, what you saw was a miniature version of a common carboy failure. Obviously, with far less potential for mayhem.

It's thermal shock in both cases: the bottom of both your bottle and the typical carboy is far thicker than the sidewalls. Applying anything other than a gentle temperature change can cause the sidewall radius to expand far faster than the bottom radius, resulting in micro-fractures that accumulate...

Cheers!

[edit] It works in both directions, of course, so even if you crept up the temperature scale in the oven, you'd also need a very slow cool-down...

 

[biochemedic]

Heating in an oven seems like a rather bothersome way to sanitize! Star San is super easy, especially if you spring a few bucks for a vinator. Don't Fear The Foam!

 

[james_cornell]

okay, got it

but just to confirm, because I ride a bike everywhere, the agitation of the bottles from riding wouldn't be the cause, right? It wasn't a bottle that exploded from pressure, just broke.

 

[FloppyKnockers]

I do that as a party trick sometimes. Fill a bottle half full (Half empty for you pessimists). Hold the neck flush with the top of your fist. Palm smack the top of the bottle. Results are just like as you described.

 

[day_trippr]

okay, got it

but just to confirm, because I ride a bike everywhere, the agitation of the bottles from riding wouldn't be the cause, right? It wasn't a bottle that exploded from pressure, just broke.

I expect the bike ride just finished the job.
It was a latent failure that went critical...

Cheers!

 

[Fatdog]

Yes a glass bottle is only as good as the fabricator who made it. Sometimes they do get weakened. I had this happen to me once (in 15 years of bottling) where the bottom just sheered right off, but without the explosion. When glass goes from hot to cold to hot and back to cold over and over again it begins to weaken the "seams" and there are more seams than you think in a beer bottle. I look for the heavier duty bottles to bottle my beer in. Stone & Speak Easy are two of my favorites to reuse as they are thicker walled and have less seams in their bottles. Hope this helped.

 

[bkboiler]

yep, the other posters are correct...
most glass is formed at elevated temperature and the cooling process results in a net compressive stress at the surface of the glass.
this has a natural anti-crack effect which is necessary, as glass (as we know) is quite brittle/fragile.
when glass is held at elevated temperature afterward, the stresses are "relieved" and the anti-crack property is lost.
borosilicate glass is much less brittle and can sustain higher temps than soda-lime-silica glass which your bottle is made from

 

[jrgtr42]

okay, got it

but just to confirm, because I ride a bike everywhere, the agitation of the bottles from riding wouldn't be the cause, right? It wasn't a bottle that exploded from pressure, just broke.

Exactly. Likely the shaking from the ride, (and maybe putting in the drawer a bit too hard, perhaps?) was the immediate cause of the failure, but most likely the sanitation was the proximate cause.
Like the guy who keels over from the heart attack, but not mentioning the years spent eating the bacon double cheeseburger for lunch every day being the reason.
Also, like others have said, rethink your sanitation procedures.
baking works, but with the potential of just such an occurance.
You didn't say if you use bottles over and over, but these things add up.
I would recommend getting rid of any other bottles you're bake-sanitized, and replace with new, to be safe.
My sanitation regime (and others as well,) is to rinse the bottle well when emptied, let dry out, then store in a closed box till bottling time. Rinse again, (with a visual check that there isn't anything funky in there) then dunk in Star San solution for a couple minutes. Dump that out, and store in box upside down with a clean paper towel underneath till filling time.
I've never had an issue with bad bottles, and the only one I;ve ever had bomb on me was a growler I filled (used to fill a couple of those with same procedure, never an issue with carb or sanitizer) with a Hefewiezen, this one turned out to be super-thin glass. I haven't used that manufacturer since, and I;ve bottled into growlers on and off all along.

 

[k1ngl1ves]

Oh my God! The dangers of glass bottles! You are lucky you're not dead! These things are time bombs!

Switch to PET as soon as possible! Don't risk your life for glass! It's too dangerous!




I figured I'd have a bit of fun before the glass carboy haters come through this thread...