Beersmith mash schedule issue?

[Steampunk]

Never seen this before and could use some input.

Making a festbier with Mash schedule set for

131
146
158

What's odd is I am getting an expected final og of 1.017. But if I move the beta rest to 147 it drops to 1.010. That seems extreme.

Thoughts, input or advice on this would be much appreciated.

 

[Oginme]

BeerSmith models the fermentability of you wort based upon the activity of both alpha- and beta-amylase enzymes.

As you decrease the mash temperature below 147 F, the activity of alpha amylase is very low, so you get a lot of chain splitting but not a lot of maltose generation. The model the software uses is quite abrupt in curtailing the fermentability results below this point. This holds for a single infusion profile and I am not sure how accurate it is for a step profile such as you are trying to use.

Depending upon how much time you spend at 146 F before increasing the temperature to 158 F, your actual results may be much lower than the 1.017 BeerSmith is predicting. If this is the case, you can adjust the slope and center point of the fermentability out of mashing in the software under advanced options. Since this is a universal setting, it will affect you other mash profiles as well, so be careful how you adjust it.

 

[Gavin C]

That's really surprising. I think the predictive power of the BS algorithm in FG is imprecise at best. Usually it overestimates FG slightly IME.

I did a similar brew to yourself today. A Vienna Lager.

Step Mash Used


Predicted FG


I'm seeing the dramatic changes you describe when I up the Beta rest to 148F
Predicted FG drops to 1.010. It is clear conversion occurs at 140F. The wort was crystal clear before adding the infusion to raise it to 156F

Adjusted Beta Rest to 148F


New Predicted FG


I guess time will tell how accurate it is.

 

[Steampunk]

Lol great now I have a gamble on my hands.

 

[Oginme]

Lol great now I have a gamble on my hands.

LOL, I consider it a learning experience anytime I make a major adjustment in my mash or equipment profiles. While BeerSmith is pretty good for the majority of times, every once in a while it just cannot duplicate reality.

 

[Gavin C]

Just an update to the thread

My Vienna lager finished at 1.009

Beersmith was predicting 1.015

FG 1.009

 

[weirdboy]

Personally, I have never trusted Beersmith's predictions on FG. However, I generally come up with a mash profile to match my goals before I enter it into Beersmith anyway.

 

[Steampunk]

Thanks for the update. I will post mine as well.

 

[Qhrumphf]

I've found BeerSmith to be pretty good about FG with all malt higher temp single infusions (154-158), overestimate slightly (say, predict 1.012 and get 1.010) in the midrange (150-154), and more significantly below 150 (say, predict 1.010 and get 1.006). Throwing adjuncts (be it grain or sugar) throws a wild card where it's all over the board, and step mashes do the same.

 

[Gavin C]

With single infusions I too usually see the predicted and actual FG to be within a point or so. No issues there whatsoever.