I just tried this yesterday and through my research, there were two schools of thought about adding extra grain to compensate for the technique used. It seemed most did indeed favor adding extra grain because the efficiency is reduced. Threads here will back up the fact that you can get 70-80% efficiency using this technique but that it begins to drop as you get into higher gravity beers. That said, I did not plan for no sparge until brew day and went with what I had adding DME at the end to get to my near-target OG. I am already planning a second batch of my 1.080 beer and to compensate for the low OG, I added more grain and to compensate for the lack of MLT space (10 gallons max) I removed 1.5 lbs of base grain and opted to include DME it's place.
Question for the no-sparge crowd, which I have recently joined.
How are you guys setting up Beersmith 2? Similar to BIAB?
Basically what I did, and I believe this is a pretty solid idea, is I first went to the mash profiles and copied medium body (what I needed) BIAB. If you are a BIAB brewer then the next step is something you have to remember you did because it will change things for all BIAB profiles.
I changed the name of the profile to No-Sparge Medium body. I went to Options>Advanced and changed the grain absorption for BIAB to .96, which is what I have for traditional batch/fly sparging method. This is the option that changes all BIAB grain absorption so you have to remember that you did it if you're finding your volumes are higher than expected. BIAB method will result in the grain absorbing less water I believe, so just keep that in mind.
Going back to my mash profile on the recipe, I removed "mash out" and I reduced the step time to 60. I read that people who use no-sparge method will maybe step for 75-90 minutes. I have not done that myself. Much of the conversion happens in the beginning so I was unsure if the additional time was worth my while. Someone can weigh in on that.
I did check off "adjust mash vol for deadspace" and input my MLT deadspace, which I had already measured. I also ensured my MLT temp was the average temp that I usually use it at. Adjustment for deadspace is unchecked in the BIAB method for obvious reasons.
Basically, these are the few adjustments I made and found BIAB profiles to be the closest to no-sparge method.