I figured as much, but I thought BIAB was for smaller batches, up to 5 Gal, and involved dunking, spraying (i.e. sparging) and otherwise a grandiose way of steeping grain within the brew kettle. I just thought it was a conceptual thing that could be brought over to all grain mashing in the tun first, prior to vorlaufing, then sparging, and collecting into the brew kettle. I just hadn't come across anything yet where someone applied it to the turn first. I'll give a whirl.