A little while ago I had a woeful brew day with my exposed element crown when trying to do a stepped mash, didn't circulate the wort enough had massive caramelisation on the element. It came to the boil, I added my hops, then the boil died and it never came back up, thermostat (I assume) kept cutting it out... It was a school night and already about 11pm by this stage so I ended up draining the urn into a fermenter and sealing it up (think cubed) and filled urn with water to soak the **** off, then next day scrubbed the life out of it, put my 'cubed par boiled wort' back in and proceeded as normal... had to guess a bit as i had already done my first hop addition before the disaster. IBUs ended up OK, but the beer was ****, I think HSA was an issue perhaps transfering the beer in and out of the urn while ~95 degrees (i could of used the urn tap, but it had blocked with hop flowers!). worst brew day ever. I nearly threw the whole damn urn in the bin.