Imploding Starter?? Shattered erlenmeyer.

[smokyjoewood12]

I made a 2L starter in a 5L erlenmeyer of Abbey II, covered with tinfoil, no stir plate. I checked on it after about 10-11 hours and it wasn't quite at high krausen so I grabbed it around the neck and swirled it. I heard the sound of gas running through a channel very quickly and then the erlenmeyer (Pyrex) exploded from the bottom. Yeast and wort everywhere. I had assumed it EXploded but I noticed that the tinfoil was severely dimpled around the mouth like it was sucked in, not out, it clearly imploded and shattered the glass. I'm so confused. Any ideas how or why this happened??

 

[JonM]

The foil probably got dimpled as a result of the wort rushing out of the other end. That is, it did get sucked in, but not until the wort rushed out and created vacuum pressure in the space between the foil and the top of the wort.

But that sucks, man. I know those 5L flasks aren't cheap. Glad there were no injuries.

 

[FarmerTed]

The stir bar probably cracked the flask while you were swirling it, or you ticked the side of a counter and didn't realize it because the flask broke at that moment.

 

[passedpawn]

Do you heat the Erlenmeyer on the stove? If so, it was probably already cracked around the base and just ready to fall apart.