Yesterday we made a Weizenbock whose grain bill was made from 50% wheat malt. The bed compacted so badly that we didn’t even finish the first vorlauf when the trickled to a halt. Because we had no hulls or other clever additive our solution was to reset the mash and re-vorlauf. There’s a window of oppurtunity while the runoff is relatively clear to collect wort; maybe a gallon’s worth. However after that gallon is collected then the grain bed hardens up again. As you can guess we had to reset the mash 6 to 8 times in order to collect the full boil volume – a pain in the ass and a time waster.
The bright side to all this is that we learned that one can always get a beer out a stubbon mash, it just might take some time.