Today I came across a neat method of reducing boil-overs when batch sparging. I'm using a 5gal cooler as mash-tun and a 30qt turkey fryer pot as boil kettle. Needless to say that I needed to watch boil-overs very closely.
But today I didn't. I ran the first sparge and collected ~3 gal into the kettle. While the mash was resting for the 2nd sparge, I brought the run-off in the kettle to a boil and it was foaming heavily. But there was enough head-room left and after a while the proteins that cause the foam-over coagulated (hot-break) and the heaving foaming subsided. Then I ran the 2nd sparge, got to about 4.5 gal in the kettle and brought it to a boil again. Now it didn't foam so badly since less uncoagulated protein was in the kettle. The 3rd time around, when I had the final 6 gal in the kettle, there was not much head room and not much foaming either.
This definitely helps me to relax at the beginning of the main boil, especially with my 30qt pot.