BeerSmith 2 Expert needed

[Justin Davenport]

So the grain does appear to make a difference although I still 1.5 litres too much wort. The pre-boil gravity is low too with the brewhouse efficiency set to 70%. I am just boiling off the 1.5 litres and will take another reading then...

 

[Justin Davenport]

OK. Here's where I am at for anyone who might be interested:
My set up is:
Plastic mash tun, 50 litre boil kettle/HLT, I have been fly sparging but decided after reading a few reports on the efficiency of modern grains that a batch sparge would suit me time wise and I would take the hit on extra grain to compensate.
In BeerSmith, I have reduced the absorption rate to 0.79, my brew house efficiency is down to 58%. I punched these figures into the recipe I have just brewed today and the numbers now seem to stack up.
Now I know these efficiency figures might look horrendous but if it gets me a predictable brew day then I will be happy!

 

[The-Engineer-That-Brews]

Apologies for being late to the party on this topic, but the way I calibrate my ’grain absorption rate‘ is simply the volume of water I put in to the tun (including sparge), minus the volume of wort I get out (plus any un-recoverable dead space), divided by the grain weight.
I think I only did this calculation once and just use the same number every time… seems to work fine for me.