‘No Sparge’ technique

[DBhomebrew]

I realize this is a bit of a tangent from the intention of the OP, but…

For those that BIAB and sparge to hit volume:
Do you get better conversion by sparging the grains to hit volume as opposed to just mashing in at full volume?

I ask because I always get better efficiency with a higher water:grist ratio and it seems to me that while sparging may rinse some sugars, I can’t wrap my head around why I wouldn’t get that rinse by just mashing with more water to begin with.  (Anecdotally, the bigger the beer, the worse the conversion efficiency.  I think this is partly the reason for the advice to “adjust your efficiency down when brewing that Barleywine!”).

And while I’m diving in, does an ideal water:grist ratio for BIAB exist?

It’s the lauter efficiency that takes the hit. Given a constant pre-boil volume, a higher OG requires more malt. More malt soaks up more water. A higher percentage of the total water volume is lost to grain absorption. Hence, a lower lauter efficiency.

My 4% beers get ~90% mash efficiency. ~75% for the big 10% beers. Conversion for all is 98-100%.