...even if you don't think it will blow off, use a tube anyways!
I started a batch of Belgian Pale Ale on Saturday, and pitched some WLP530. I had a lag of about 24 hours, and by Sunday night, it was starting to slowly bubble. By Monday morning, there was a thin layer of yeast on top, and by Monday night, a thicker krausen which appeared to be climbing. Did I take the hint? Heck no! "It isn't even a big beer, and there is enough headspace, it should be fine," I told myself.
I went into the basement this morning, to be greeted by the aftermath of a yeasty bomb blast. The carboy was sitting in a puddle of yeast, and yeast was flowing down the sides. There was yeast splattered on the wall, and on the fermenters nearby. The inside piece of the 3-piece airlock was on the floor, and there was a perfect ring of yeast on the ceiling from the impact of the airlock lid (the lid, by the way, was nowhere to be found. Perhaps it was atomized
If I had a split personality, one of them would have told me "I told you so." I rigged up a quick blow-off tube and cleaned up the majority of the mess, and had to run to work with no time for breakfast. So yeah...lesson learned! I'm just glad that I do my fermenting in the unfinished side of the basement, so nothing was permanently stained or damaged