Originally Posted by thehopbandit
Interesting. I wonder why there is the difference in treatment by Jamil in BCS and by BeerSmith? Beersmith accounts for very nominal increases in OG due to steeping grain, while Jamil assumes that the steeping grain will (roughly) yield similar results to mashing (70%). Which is closer to reality?
In the past, I have entered in extract recipes from kits I have purchased using the extract (not partial mash) setting and they seem to be spot on with the OG. Using BCS logic, I should have seen a much higher OG as a result of the steeping grains. That's why I am a little bit leery to go with the fact the BCS recipe assumes a MUCH higher yield from the steeping grains.
I understand the logic behind each, but it seems like to me that the way BeerSmith handles the calculation makes more sense than assuming the high steeping yield that BCS does.
I appreciate your help.
To understand where the discrepancy comes from, it is necessary to understand how brewing software such as Beersmith and Promash estimates the OG, and how the OG estimates were derived in BCS.
When doing all grain recipes, you need to specify a conversion efficiency percentage, which indicates what percentage of the potential sugars can be extracted from the grains during the mash/lauter process. The software multiplies the maximum theoretical extraction from the grains by this percentage to estimate the pre-boil gravity.
The conversion factor is only used for grains. If you add extract or sugar, they are treated as 100% convertible as all conversion (if any) has already been performed.
Using Beersmith or Promash, you can make a recipe using only extract and optionally sugar, and the predicted OG will not change if you select extract, partial mash, or all grain; even if you specify different conversion efficiencies for partial mash and all grain. (You cannot specify an efficiency for extract.)
If you use either program to make a recipe using only grains (either base grains or specialty grains) and specify partial mash or all grain, then the predicted OG will change in proportion to the efficiency. This is not completely correct, as if you make a recipe using only specialty grains, there will be no enzymes to convert the starches to sugars, but the software assumes that you know what you are doing, and you have specified the conversion efficiency.
If you make a recipe that contains both extract and specialty grains, and specify a conversion efficiency, then the software will convert the extract at 100% and the grains at the specified efficiency. Although most homebrewers would consider this to be an extract brew, the software considers it to be a partial mash, as with extract there is no way to specify the efficiency.
The help system in Promash has an entry under the heading "Extract Recipies with steeped grain". It explains that you should select Partial Mash as the brew type and goes on to say that you need to change the efficiency rating to account for steeping grains as opposed to mashing. It suggests that 30% is a good average number for this.
My version of Beersmith (version 1.4) does not give any help on this topic, but you can do this. It will give different results to using Beersmith to develop an extract recipe. If, using Beersmith, you develop the recipe as extract, then it automatically sets the efficiency rating to 15%. (Promash leaves the efficiency rating at whatever it was set to for all grain.)
BCS. explains that the recipes assumes an efficiency rating of 70%, which I know is unreasonable for steeping grains, although it is acceptable for an all grain recipe.
I must admit that I don't know whether the Promash suggestion of 30% or the Beersmith assumption of 15% is more reasonable, but 70% is way out of range.
Hope this helps