This is not meant to sound like me being a smart arse by why do you need a BIAB section in beersmith?
Can't you just adjust the mash in water volume to show a full volume mash, no sparge?
Step mashing can be done via infusion, temperature raising (HERMS, RIMS, Braumeister) or decoction and all options are there in beersmith.
Answering Smurts question and then moving on to some of the other issues.
Don't use the BIAB thingy in BS2 for a Braumeister.
BM's need a sparge.
You want zero 'kettle top' up (of plain water) or you lose sugars and efficiency (I learnt that the hard way). MHB has a great trick: put your malt pipe over a bucket once it has 'stopped' sparging to collect anymore dribbles (and can be sparged again) to hold an emergency amount that you can add near the end of the boil to bring it up to volume if you are below target volume (or use for starters).
I use BS2 and BM. One of the complicating factors is that
you don't mash in with a full volume per se. That would flood over the top of the malt pipe if you did and the system wouldn't work as it should (I assume). For a 55L batch you mash in at 53L or so. You have to account later for grain absorbtion (10L), evap loss (say 6L), cooling loss (say 2L), loss to trub etc (say 2L). No debate, you need to sparge with a BM to bring it up to the pre-boil volume of say 63L (example numbers only - depends on grain bill, hop amounts, boil temp & time etc). In the above example that would be a sparge of 20L.
53L into the fermenter will allow for 3L loss to fermenter trub and give you a
bottling volume of 50L from a 50L BM. You mash in with 53L NOT 63L.
In the water volumes tab, the key box to get right is the Boil and Fermentation, 'Est Pre-Boil Vol'. Set this correctly as 63 and it will tell you the correct sparge volume (but you need to have an idea of this to be able to set the pre-boil volume :lol: ).
The other key thing is to have the volume correct at mash-in with the mash profile. I make a new mash profile that follows what I am doing, they are all Temperature steps and the first is set as 53L and the rest as zero L added. I work on a rise time of 1oC per minute (it is close enough).
With the BIAB thing ticked in the mash profile it accounts for about 0.6L/kg of grain as absorbtion. With it unticked it is about 1L/kg of grain. I am not sure about this but I reckon I have experienced closer to 1L/kg.Ticking the BIAB thing automatically sets your mash-in volume to full volume (say 63L) which is too much for the BM,
leave the BIAB thing unticked in the mash profile.
It is a matter of working out all of the losses correctly and plugging them into BS2 in the appropriate places. Some of it is trial and error.
All the numbers above may vary for your batch, I was just working through one example.