Beersmith and Brew in a Bag

[Gibbnal]

Does anyone have experience using Beersmith for BIAB beyond the instructions on the Beersmith blog? It does not make sense to use your boil volume as your strike volume as instructed. No water absorption by the grain? Speaking of that, is there a way to adjust the grain absorption ratio in Beersmith?

And what about water lost to the grain - I've seen it stated as 0.125, 0.08, 0.06 and 0.05 gallons per pound for BIAB. I get it that it will be less than traditional methods, but how much? All help is appreciated.

 

[Mysticmead]

I modify the infusion mash to have the total water needed for the strike volume. I use .05 for absorption since I squeeze the bag. To get the total volume needed you need to know your boil off rate. so for my last brew I had 10.5lbs of grain. That's .55 gallons of absorption, plus my boil off for a 60 min boil of 1.25 gallons, plus loss to trub of .25 gallons, plus my final desired volume of 5.5 gallons. that's 5.5+.25+1.25+.55= 7.55 gallons.. I rounded it down to 7.5 gallons. Once you know your boil off rate and have a general idea on trub loss the rest is just basic math..

 

[FarmerJoe]

I've been trying to find more info on this topic as well, so I'll be looking forward to replies. From my personal experience with my 1 BIAB brew, I was doing a 2.5 gallon batch in a 5 gallon pot and used about 5.5# of grain. I started with 3.7 gallons total water, as suggested on this site. I boil off about .75 gallons an hour, so that would about 2.95 after pulling the grains out, squeezing the bag, and boiling. So that grain bill absorbed about .70 gallons just about. I ended up with almost exactly 2.5 gallons, maybe just off by .03 or so. I haven't calculated the percentage yet, but all the numbers are there. Of course, your setup might affect boil off amounts as well.
Hope I contributed a little

 

[Gibbnal]

I modify the infusion mash to have the total water needed for the strike volume. I use .05 for absorption since I squeeze the bag. To get the total volume needed you need to know your boil off rate. so for my last brew I had 10.5lbs of grain. That's .55 gallons of absorption, plus my boil off for a 60 min boil of 1.25 gallons, plus loss to trub of .25 gallons, plus my final desired volume of 5.5 gallons. that's 5.5+.25+1.25+.55= 7.55 gallons.. I rounded it down to 7.5 gallons. Once you know your boil off rate and have a general idea on trub loss the rest is just basic math..

Thanks! That's exactly what I was looking for - and my next batch actually has an identical grain weight to your example.

My CB20 boil off was 0.75gal/hr, but I retrofitted a new 9gal kettle with two elements and have not checked the new boil off. I am going to estimate it at 1gal/hr for now. Still have to figure out what % to set the PID to get a good boil without going overboard. I appreciate all the replies.