Cold bottles went warm then exploded in fridge???

[DownToFerment]

How does variation in temperature effect the possibility of exploding bottles?

Recently, I bottled a partial mash dark ale that I've made a few times before. Everything I did in my brewing process was the same. Usually I let the bottles condition for weeks if not months in a cabinet in my kitchen, which holds a good constant 70 degrees. Then I cool them down in the fridge and enjoy without a problem.

This time around I let them condition for about 2-3 weeks before storing them in my 40 degree keggerator. I grabbed six for a party and drove from Sacramento to San Diego. The bottles were in the back on the floor in a cardboard holder, standing upright. There were a few bumps along the road and the bottles fell over a few times. As soon as I got to San Diego I threw the bottles back into the fridge to cool them down to enjoy. About five or ten minutes later, I loud pop was heard and I checked the fridge. There was beer and shards of glass everywhere - three bottles exploded.

I took the other three out and opened them ASAP. All three volcanoed pretty good, and I saved about half of each of the remaining three bottles.

The other bottles that are still in my freezer home are still good, and they don't foam up when I open them, they're practically picture perfect.

Perhaps my yeast wasn't done after the 2-3 weeks before I put them in the freezer and they kicked back up sitting for 7 hours in the car? Where they just shaken up too much? I thought being in the cold for a few weeks would have made the yeast flocculate down and quit their job. Any ideas on why these suckers blew up? Was I minutes from having them blow up in my car or did the fridge do something to make the beer pop?

Thanks for a great show for novice home brewers like myself!

[BDawg]

Welcome=

It is possible that you had some bottles with more priming sugar than others.
Check to see if any of the others are undercarbonated. If so, you probably just need to mix the sugar in better.

Like you said, it is also possible that the beers weren't finished fermenting when you bottled them.
Did you take a gravity reading?

Finally, it is also possible that they picked something up which the warm temps made more active.
Look for little krausen rings in the necks of your bottles, and also taste for phenolics and/or sourness. Both are signs of contamination (wild yeast or bacterial). To test this, take some of the cold ones and let them warm up for a couple weeks to see if any kind of infection takes hold. If so, you may need to replace your plastic/rubber parts that you used for this batch post boil.

HTH-

[siwelwerd]

This time around I let them condition for about 2-3 weeks before storing them in my 40 degree keggerator. I grabbed six for a party and drove from Sacramento to San Diego. The bottles were in the back on the floor in a cardboard holder, standing upright. There were a few bumps along the road and the bottles fell over a few times. As soon as I got to San Diego I threw the bottles back into the fridge to cool them down to enjoy. About five or ten minutes later, I loud pop was heard and I checked the fridge. There was beer and shards of glass everywhere - three bottles exploded.

The fact that they exploded in the fridge is probably a red herring. You are probably lucky they didn't explode in your back seat. Sounds like they were overcarbonated to start, and the bouncy ride/jostling caused some CO2 to come out of solution until the bottles reached their breaking point. In general, cooler temps cause the beer to absorb more of the CO2, so cooling them down will prevent excess pressure in the headspace, while warming them up will cause CO2 to come out of solution (PV=nRT).

If you are following BDawg's advice and warming up some bottles as a test, I would put them in an enclosed space in case they are infected or overprimed and build up pressure and explode as well. I would try to keep any remaining bottles cold until opening, or stored somewhere that will contain exploding glass.

[DownToFerment]

Thanks for the info! I checked the necks and I don't see any krausen rings. Pop'd one open just now and it was fine. A little foamy but not unlike anything commercial. I can't taste any sourness to it, but after all the suggestions I'd probably bet on too-much priming sugar.

Oy, this is why I keg.

[hoodie]

The fact that they exploded in the fridge is probably a red herring. You are probably lucky they didn't explode in your back seat.

+1 Always assume human error first.