I believe I see the same issue, but can give a different view of it that might be a little more descriptive of the problem (hopefully). The thread exists on HBT (
http://www.homebrewtalk.com/f36/steeping-grains-adding-gravity-294583/#post3663000), but I'll cut / paste it below.
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mmonacel 01-13-2012 09:56 PM
Steeping grains adding gravity?
I'm looking to do an all-grain Janet's Brown from JZ's BCS book (page 143). Below is the grist. Everything but the 2-row and Wheat Malt are listed as "steeping grains". I plan to mash them like I always do. The books lists the OG as 1.066, but BeerSmith and my own calcs show 1.074. Now if I exclude the steeping grains from the gravity contribution calculation it comes to 61, which is closer, but still a bit off. All ppp/gal figures are from BeerSmith. Where am I going wrong here?
Code:
Grain ppp/gal pounds Gravity Contribution
2-row 37 12 56.51
Wheat Malt 40 1 5.09
Cara-Pils 33 1.25 5.25
Caramel 40 34 1.25 5.41
Chocolate 420 35 0.5 2.23
gallons 5.5
efficiency 0.7
Total Gravity Points 74.49
mmonacel 01-13-2012 10:00 PM
sorry - above was the best table-like formatting I could do
jdrowell15 01-13-2012 10:06 PM
Does your efficiency in Beersmith match the recipe?
mmonacel 01-13-2012 10:29 PM
Yes - all the BCS recipes are set to 70% and BeerSmith is also set to 70%. Since my calcs and BeerSmith's calcs come out the same I think the entry is good.
jdrowell15 01-13-2012 10:34 PM
I remember BCS does extract first and then tells you what grains to replace the extract with. Maybe they give the gravity for if it was brewed extract and not all grain. When you brew extract you are not converting the specialty grains to sugar where as you are in all grain. That could account for the little difference you are seeing.
jdrowell15 01-13-2012 10:36 PM
Steeping grains and specialty grains are typically one in the same. Though not always.
mmonacel 01-13-2012 11:27 PM
I think I found it... It appears to be an issue with batch size.
My "batch size" figure in BeerSmith is set to 5.5 gallons. This is because BS defines "batch size" as what goes into the fermenter. You can see this in the Classic Recipe view where it shows "Batch Size (fermenter)" as well as the help files. In BCS all recipes are 6 gallon recipes and assumes .5 gal loss to trub and chiller (ie. 5.5 into fermenter for 6 gallon recipe) and .5 gal fermenter loss (which equates to 5 gallon bottling). This is also how my equipment profile is set up.
Unfortunately if you enter in a 5.5 gallon batch size for the recipe, all the volumes work out (volume into fermenter and bottling volume) but the gravity contributions do not. If I put 6 gallons in for a batch size, my gravity contributions work out (in this case they come to 68 which is almost spot on) but the fermenter and bottling volumes are .5 gallons off.
Hmmmm... is this a bug in BeerSmith or am I thinking about this the wrong way?
mmonacel 01-13-2012 11:29 PM
Maybe the "bug" is simply the display of "Batch Size (fermenter)" in the classic view not taking into account the chiller / trub loss...