I do all-grain BIAB 5-gal batches of dark ales, and have been quite satisfied with the results. My procedure has been to do a single-infusion mash at the low end of the spectrum-- initial strike temp about at 152 F to 155 F. Turn the burner off, stir in the crushed grains, put the lid on the brew pot, cover it with an old insulated coveralls to retain heat, mash for 60 minutes, remove grain bag and drain, heat to boil and continue with the rest of the normal brewing process.
If at the end of 50 minutes of mashing, I would suspend the grain bag above the liquid in the pot, and heat the water to ~ 190 F, then submerge the grain bag again and leave it for 10 more minutes, would that step improve the beer?
Thanks in advance for your comments.