Beersmith fermentable/unfermentable calculations

[kontrol]

I was wondering if you guys know if Beersmith Estimated OG and Estimated FG calculation consider the unfermentable sugar from crystal? Is it the dry yield?

I'm playing with a recipe that might have too much crystal but I'd like to know if the estimated FG is really what it should be.

 

[Yooper]

No, I don't think Beersmith accounts for the fermentability or lack of fermentability of ingredients very much.

The OG should be right on, but the FG might not be.

Crystal malt does have fermentables, though! It's not unfermentable.

 

[kontrol]

No, I don't think Beersmith accounts for the fermentability or lack of fermentability of ingredients very much.

The OG should be right on, but the FG might not be.

Crystal malt does have fermentables, though! It's not unfermentable.

Yeah I know it's not all unfermentable. I also remember from John Palmer that the higher the Crystal Lovibond the higher portions of unfermentables.

I'm asking because I saw the "Dry yield" or just "Yield" in the ingredient profile. Honey and crystal have lower Yield than Sucrose, dextrose or LME and DME. So it made my think it was to calculate the OG and FG accouting unfermentable.

 

[tgmartin000]

I've heard the opposite of yooper, that beersmith does take the fermentability into consideration. But the fg calc has never been too close for me anyways.

 

[JeepDiver]

It does take them into account on FG, as well as the mash profile. My FG is usually close.

 

[kontrol]

Different opinions here. My experience is pretty low (1 batch) but I did hit the OG and FG pretty close. I should try to find on their website maybe it's said somewhere.

 

[Yooper]

My FG is never all that close to predicted. But I predict it myself, based on my mash temp, the ingredients, the yeast strain's attenuation, etc.

Beersmith 2 is better than 1.4 (100% corn sugar was the same FG as 100% malt in the FG) but it's not all that good in my opinion. It will often tell me my stout "should" finish at 1.012, but in my experience it always finishes at 1.019-1.022. Quite a bit of difference.

Edit- for fun just now I put only corn sugar in the fermentables in Beersmith. Og was 1.065, which would be correct. Fg predicted is .985 (not possible). .990 IS possible. Not a huge difference, but not really all that close either. For all base malt, OG of 1.065 with WLP001, and a 156 mash temp, a FG of 1.017. Same grainbill with a mash temp of 148, the predicted FG is 1.010. Not too bad, but I'd get lower than that for sure mashing at 148- more like 1.005.
Adding 1 pound of crystal malt 40L did not change the FG predictions at all.

 

[chickypad]

I've seen Brad Smith confirm this as an issue before on the Beersmith boards in relation to how it treats lactose as fermentable. I just put in 10 lbs of crystal 60 as the entire grainbill on a 5 gallon batch mash at 150* and it estimates it'll go from 1.049 to 1.009. So it's clearly not taking into account individual grain fermentability.

I think the reason overall FG estimates aren't that far off is that crystal malt is usually a small percentage of most grainbills. Also, as nilo showed in his thread, mashing with a base grain does increase the fermentability of crystal malt. I do find that Beersmith underestimates the FG by a fair amount on most of my beers with a high percentage of roasted grains.