I am not a brewer, and truly understand that you know more about this than I, ThirstyBoy.
But I choose to believe there is a place for sparging when BIAB'ing.
I mash in about 4-5 litres/kg of grain.
I then sparge with at least 3 or 4 "tea kettle volumes" of 1.8 litres of water (so say 5 to 8 litres of water for 4-5 kg of grains).
I get sugar out of the grains in the form of wort rather than just throwing the grains out, I have the grains submerged in water for several minutes and of course stir before tapping the wort out through the tap of the fermenter.
Maybe I could have achieved the same mashing full-volume, but it seems to make sense to me to mash with water to grist ratios as mentioned by Palmer
(link), BYO.com
(link) rather than mashing in full volume.
It also (at least to me) seems to make sense to sparge/rinse the grains with more hot water after pulling the bag in order to increase the amount of sugar extracted rather than just ditching it. I don't squeeze and I don't do it excessively but still sparge, though
So I would think there is value in putting hot water on the grain bag one way or another, the method probably only decides how much more extract is extracted?
And after all, most of the fun here is fiddling with a new process to make the production of beer more brew-like and less clean-sanitise-mix-with-water-then-clean-again :lol:
That's why we like to add all these steps like finings, cold conditioning, yeast starters, whirlpooling, etc. To keep adding new tricks and techniques to our brewing. That in itself may make sparging a valuable process for us poor BIAB'ers as well, even if it had no "real" merit.
Sorry for going completely off-topic here Nick, guess I should have asked this question in a new thread.
thanks
Bjorn