Exploding bottles, what the heck?

I bottled some porter last April in swing tops. Had one the other week and seemed over carbonated. Last night I was cleaning and heard a pop; knew exactly what it was. These are pretty heave glass too.
I have had this happen to several beers I cellar for long periods. The yeast I used was a dry fermentis I can’t remember the type, just that it was in a light green packet. And I know it didn’t flocculate very well.
So what do you think is going on? Usually I FC! But this one I think was bottle conditioned. Too much priming? Or is it there’s still some fermentation going on? I have a dry stout that was FC’d, tastes fine except it is now overcarbed has that co2 taste. Is it just some beers need to be consumed faster?

How many bottles exploded? Just one, or more? Have you opened others and are they gushers?

The light green sachets are S-33. Too much priming sugar would make it overcarbonated, but not enough to explode unless you added several times too much. Either the beer was actually stuck and not done fermenting or got infected.  If it was just one bottle, it could have been week glass.

Bottle bombs can be caused by a rush to bottle (incomplete fermentation), overpriming, and/or infection. 
All  of these things must be avoided, especially if you’re going to cellat your beers for extended periods.
Rushing it into the bottle is a very common cause.

This is my bet. How are you verifying that fermentation is complete before packaging?

There’s always the possibility of wild yeast in those particular bottles. You could have hit all your targets and still have bottle bombs if they sit long enough.

It sat for like four weeks after fermentation complete. I was waiting for the suspension to drop out. Turns out All we’re gushers. Dang dumped the whole batch! I think euge is right. Swing tops. May pasteurize the long storage beers next time

I’m not sure why swing top bottles would increase the possibility of wild yeast.  I’ve stored beer in swing tops with no problems.  We’re the bottles clean?  Were the gaskets and the swing top itself sanitized?

I’ve had over-carbed beers leak out through the gasket, but I can’t imagine that anything is being drawn in to the bottle once it’s capped.

I wasn’t speaking about swingtops but just his batch being in bottles overall.

Got it.  I mis-understood.

Definitely sounds to me like the the beer got infected somehow.  Assuming it was at a stable final gravity at bottling.

  1. Are you verifying that the gravity is indeed steady for at least 3 days before “It sat for like four weeks after fermentation complete”? Racking to a secondary too soon can put yeast into a dormant state. Adding sugar at bottling can wake those same yeast up, causing an extended refermentation in the bottle.

  2. You have not mentioned any off-flavors. Are there any? If so, you may have unclean bottles that have resulted in over carbonation. Sometimes this presents with flavors ranging from “slightly rubbery” to “somewhat plastic” to Band-Aids all the way to “a turd covered in burnt hair”.

this makes me think that you are not cleaning your bottles well enough. If this dry stout was force carbed and is still getting overcarbed it almost has to be an infection, either wild yeast or some kind of brewers yeast that has a much higher attenuation factor than whatever you used as your primary strain. If your beer was done when it went into the keg and it went in the bottle from the keg fine there is no reason for it to become over carbed unless infected. Even if it wasn’t done all the way it’s unlikely that it stalled so high as to cause bottle bombs.

I have a batch that got a wild yeast infection - something going toward Brett, but more like smelly gym shoe.  It was a ten gallon batch that I fermented side by side - five gallons in a bucket and five allows in a Better Bottle.  The kegged batch was carbed and held in refrigerator and the Beeter Bottle is still downstairs.  I moldy film started to appear on the Better Bottle and once I got to the keg (a month or so later), I tasted the off flavor.  No bottle bombs, but an infection that likely happened during the cooling process…

Really best to store any beer, especially beer with live yeast in the bottle/keg, under 50 degrees if at all possible. This may sound crazy, but I wonder sometimes if US-05 doesn’t have some latent fermentation activity. Seems like beers made with that strain always seemed to have continued activity if not kept cold in bottles or kegs.

That’s strange. I use US-05 for at least half my beers and I’ve never noticed an increase in carbonation over time. I don’t filter (or even cold crash) before bottling, and I’ve had brews sitting in the cellar in the mid 60’s for well over a year with no problems. Maybe you got a bad batch?

I imagine the good Major has used more us-05 than the rest of us combined.

Could just be a coincidence but I have beers that have sat around for years and never over carbbed up but a few US-05 bottle beers have. Never really had the problem with another strain.