Problems with custom Mash Profile

[Theo24]

Hello everyone, I am happy to be part of this community!
I recently bought BeerSmith 3 Gold and I have setup a custom mash profile for a Hefeweizen recipe. \
The mash profile is attached here as a .bsmx file.
I need to point out that I have checked the "BIAB Mash with full Boil" because i decided that i will not do any sparge at all.
My equipment is the VEVOR 30lt all-in-one.
The problem is that whenever i select this mash profile in my recipe, the estimated final gravity is way too low for no apparent reason.
So, if i select the default "Single Infusion, Medium Body" mash profile, the estimated FG is 1.009 while with my own mash profile FG is only 1.004!
I have also attached a screenshot of the Design page of this recipe, just in case.
Thank you for your time and i hope there is someone here who can help me on this!

 

[GigaFemto]

I believe the culprits are the acid rests. There is no reason to do an acid rest with modern malts and proper water modification. The extended time at low temperature will give you a highly fermentable wort that results in low FG. If you just do the last 3 steps for saccharification and mashout you should get good results.

--GF

 

[Theo24]

I believe the culprits are the acid rests. There is no reason to do an acid rest with modern malts and proper water modification. The extended time at low temperature will give you a highly fermentable wort that results in low FG. If you just do the last 3 steps for saccharification and mashout you should get good results.

--GF

I removed the 2 acid rests, although i believe the ferulic acid rest is still "necessary" to achieve something close to the original beer profile.
But even without the 2 rests, the FG stayed the same.
It seems the problem was the double saccharification step, when i deleted the 1st one, the FG went to normal values, something like 1.011.

But is that a bug in BeerSmith? Doesn't make any sense at all...
If i delete the 2nd sac. step (alpha) then the FG is again too low.
It seems the problem happens only because of the beta saccharification step at 63degC. Weird...

 

[GigaFemto]

Hmm, OK. I guess the acid rests are outside the range of temperatures for BeerSmith to consider them for saccharification. The beta rest is pretty low, though. 148 F is more typical. If you go into Options -> Advanced you will see a section titled "Adjust Final Gravity Based on Mash Temperature". There is a formula there (that you can change if you wish) for the effect of the mash temperature. The default is to adjust the attenuation by -1.25 %/deg-F, with a center point of 153.5. The apparent attenuation is ((OG-1)-(FG-1))/(OG-1). That means that a mash temperature of 145.4 F would have attenuation of (153.5-145.4)*(1.25) = 10% higher than 153.5 F and 3.25% higher than 148 F, and 13.5% higher than the other rest at 156.2. "Single Infusion, Medium Body" mash profile uses a temperature of 152 F, which should give an estimated attenuation that is 8.25% lower than a single rest at 145.4 F. For your OG of 1.050 and an estimated FG of 1.009 from the single infusion, the attenuation would be 82%, so an attenuation 8.25% higher would be 90.2%, giving an FG estimate of 1.0049, close to the 1.004 you listed (there are probably a lot of rounding errors in my calculations). You can uncheck the box and not use that formula at all, if you want. The point is that lower temperature mashes cause BeerSmith to estimate a lower FG. This is only true for temperatures within some range that BeerSmith considers saccharification. I don't know the bounds of that range, but it seems your acid rests are outside.

--GF