I am probably a bit of a fanatic when it comes to Beersmith calcs.
I calculate the EXACT amount of water needed and that is all I use.
I mash with 25 litres and I sparge the rest through the grain after the mash.
I have my grain absorption and boil off figures set exactly for my grain crush and my BM...do not go on the default figure for grain absorption in Beersmith unless you have measured it and found it to be correct for your crush of your mill.
I only work on "mash" efficiency as "brewhouse" efficiency can and will vary from brew to brew depending on your losses in the kettle and the fermenter.
I have a 20 litre BM and I don't use a pick up tube but I have my Beersmith set to achieve a Batch volume of 25 litres.
I chill with an immersion chiller and then remove the chiller and whirlpool and allow the wort to settle for ONE HOUR in the kettle with the lid on before running it into the fermenter.
I tilt the BM to get 20 litres into the fermenter or if no trub is coming out I continue to drain on an angle until the first lot of trub starts to reach the tap outlet.. when this happens I stop draining. I am usually left with approx 4 litres in the kettle which is break material and hop trub.
I always get between 20 and 21 litres into the fermenter which will give me 19 litres into the keg. The wort is crystal clear.
Here is my equipment profile for a 90 min boil
Equipment Profile 20 L BM 90 min boil.jpg
Here is a dipstick I made to achieve the exact volume of water required as per Beersmith calculations
BM Dip Stick.jpg
IMG_0569.jpg
Here is my grain absorption settings in "Advanced Options" in Beersmith
Beersmith Advanced Options Dicko's BM.JPG
My figure for grain absorption will differ from others...This figure however, needs to be accurate if you are to achieve repeatability.
I feel that the reason some claim that the BM loses efficiency as the beers get "bigger" is because the grain absorption figure is not correct and this results in a wort that is more diluted than it should be as the volume of grain increases.. This of course is if the absorption figure in Beersmith is higher than what it actually is in real life.
A good starting point in Beersmith for a BM is if you select the BIAB in the mash profile and work on that absorption figure which is lower than the other default.
For some time I had no other BM users to compare notes with and I couldn't seem to get any reliable figures from people that I had asked so I just relied on my own personal observations.
There is now a couple more BM owners in my area and we have come to realise that these figures vary particularly with grain crush.
I have a 3 roller Crankenstein and have it set to 1.4mm and get an efficiency of 77%. The other guys have two roller mills set to 1.2 and are getting up around 85% so I will be experimenting with my mill over the next few brews..not that I am all that worried about a few point of efficiency.
BTW the other guys "grain absorption" figures are higher than mine.
We all have 20 litre BM's and the boil off figures are very close from our recent results.
All the above are based on my observations and thoughts and is by no means "gospel" on BM brewing as each brewers situations are different.
I hope this PP type post may help some newbs with the BM :lol:
Cheers
Edted; Immersion chiller not CFWC