I've never had this happen in this fermenter. 10 gallons of beer in a 15.5 gallon keg, I've never had a blowout, until today. This is the batch I brewed on Wednesday, I pitched directly on a yeast cake from a batch I brewed about 2 weeks ago. Perhaps I should have removed some of that yeast. After I got it all cleaned up, I put on a blow off tube into a growler of star-san.
Update, next day: I need a bigger blowoff tube. I had more mess on the floor this morning. It's a good thing I'm fermenting in the garage with a concrete floor. I looked back through this blog, and found that there had been a "massive blowoff" on a previous batch of Panama Red. Hmm.
Inside the fermentation box, what a mess:
Inside the fermenter:
A shot of the Panama Red that I went to get a glass of when I noticed the mess. As it happens, it's another batch of Panama Red in the fermenter. It's hard to tell from the picture, but that beer is crystal clear with a nice rocky head. My guess is it's close to the last glass out of that keg.