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Step Mashing final gravity

Davehenry

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Hello all. I have a question about step mashing. I have a bunch of Firestone Walker clone recipes that I've been brewing and they have turned out great. However, I'd like to use all of the same brewing techniques that are used in the orginals including their step mash.They mash at 145 for 60 minutes and then raise to 155 for 30 before mashing out(I have been using a light bodied batch sparge in a cooler). I modified a beersmith step mash profile to include the appropriate temperatures but when I apply it to my recipes the estimated final gravity goes up quite a bit. The whole idea behind Firestones mash schedule is to make the wort more fermentable not less. For a stout it actually went up by 10 points! Am I doing it wrong?
 
What beersmith is telling you is that you're utilizing the enzymes better, allowing you to convert more starch to sugar with the step mash than you were capable of with a single infusion mash.  So, it stands to reason, that if you're converting more starch to sugar with the same grain bill, then your original gravity is going to go up with the step mash.

Just adjust your grain bill back a little bit for the step mash, so that you end up with the same original gravity that your single infusion mash had.

Your step mash should slightly alter the types of sugars created and make a small difference in the beer.  Whether it will be more like the commercial example or less like it can only be determined by actually making it.  Also, whether or not you prefer the single infusion version or the step mash version can only be determined by actually making it.
 
Davehenry said:
I modified a beersmith step mash profile to include the appropriate temperatures but when I apply it to my recipes the estimated final gravity goes up quite a bit.

I hadn't noticed this bug before. I created a mash profile like you described and indeed saw the rise in FG.

The wort is more fermentable, so as long as there are nutrients available, the yeast should consume it all. By raising the yeast maximum attenuation, you can effect the final gravity. I raised the yeasts' max attenuation to 78% to get the same FG as was seen with just the lower temp step.
 
Scott Ickes said:
What beersmith is telling you is that you're utilizing the enzymes better, allowing you to convert more starch to sugar with the step mash than you were capable of with a single infusion mash.  So, it stands to reason, that if you're converting more starch to sugar with the same grain bill, then your original gravity is going to go up with the step mash.

I understand that part Scott. It's the FINAL gravity that is going up. Not the Original gravity. I'm now assuming it's a glitch as I can't think of any reason this would happen.
 
Davehenry said:
Scott Ickes said:
What beersmith is telling you is that you're utilizing the enzymes better, allowing you to convert more starch to sugar with the step mash than you were capable of with a single infusion mash.  So, it stands to reason, that if you're converting more starch to sugar with the same grain bill, then your original gravity is going to go up with the step mash.

I understand that part Scott. It's the FINAL gravity that is going up. Not the Original gravity. I'm now assuming it's a glitch as I can't think of any reason this would happen.

My bad...  I had mash and original gravity in my head, because they are so connected to each other.
 
old post i know but this happens to me also which is frustrating. without knowing the science behind it, why doesn't beersmith calculate the steps during the sach rest phases; or does it? how does and why do all multiple step mash beers have their FG increased?
 
I've been trying to create custom 2-step temp mash profiles for my HERMS system. Beersmith seems to calculate the ADF (and therefore FG and ABV) solely from the temp of the second rest - no matter how long it is and no matter what the temp of the first rest is.
ANY TIPS PLEASE?
 
The final gravity goes up because you have created more long chain sugars which do not completely ferment / convert into alcohol/co2. There are residual sugars that wont convert to alcohol .They remain in the beer, and add sweetness and body to the finished beer.  You have a higher Final gravity which means you end up with a sweeter but lower alcohol beer just because of different temperatures used in mash steps. You can make the same identical beer with high and low mash temps  and get both beer with the same starting gravity; the lower temp mash will end lower than the higher one. There is such an experiment on the web.  Remember M.A.L.T. - More-Alcohol- Lower- Temperature.  A lower mash temperature ( or single infusion) would leave you with a lower final gravity, higher alcohol, drier beer. 
Performing a step mash gives you a different beer than single infusion saccarification. There are many articles on step mashing, I studied them  and created my own 4 step at one point, now I use 113f, 140f, 150f, 168f. I use this for all lagers and trappist quad ale .
 
My question is not about why lower mash temps yield higher attenuation. Its about how Beersmith deals with the effect of several rests and the temp & duration of each. I've played with simulating a simplistic SMaSH beer w custom multi-rest mash profiles in Beersmith and it appears to simply react to the temp of the second step while ignoring it's duration and the other steps. Results seem unrealistic :(
I think this is much more likely to be due to something numpty I'm doing than the software - and wonder if anyone can set me straight?
 
The problem is that mashing model that BeerSmith uses gives you a lower fermentability for short mashes at 145F.  As such, a stop at 145F does not impact the fermentability of the wort and it defaults to the fermentability calculated off the higher mash temperature.  It is not unreasonable that the software cannot handle multiple step mashes well, considering that most fermentability of wort models that I could find when researching are based upon single infusion mashes. 

I've done process control and process modeling on much more complex systems (pulp mills and paper machines) and sometimes there are just situations that cannot be accurately predicted by the models available.  Your options are to spend a lot of time and money doing a lot of testing to make a new model or a correction to the old one, or to live with the minority of times when the model may be off.  The choice usually depends upon the risk of the error introduced.  In the case of BeerSmith, the program focuses on predicting the OG, SRM, and IBU as accurately as the models allow, but less so on the FG, since that is also dependent upon a number of variables external to the mash.

Correction on the impact of the 145F temperature:  that was based upon my experience with the last version of BeerSmith and has since been fixed for single infusion points.  With multiple steps within the saccharification range, it only seems to respond when the first temperature reaches 149F or higher.  Initial temps between 145F and 148F the model defaults to the higher rest temperature for fermentability estimates.
 
I think I understand how Beersmith calculates the FG.
For my equipment setup with 75% brewhouse efficiency, the following equation predicts what Beersmith will estimate for the FG within 1%.  Inputs are OG, mash Temp and Yeast attenuation...
This is derived from Beersmith using the standard Single Infusion, No Mash Out with Full, Medium and Light body options.  I think it also applies to multi-step mash profiles, but based on the second (or highest?) step temp if first step is below 62C, although I haven't tested many permutations. (see Correction in Oginme's previous post)

FG = OG x (1-ADF)
where
ADF = 1.04 Y - 2.22 T + 146
and
FG, OG in gravity points (eg. 1.043 = 43)
ADF = Apparent Degree of Fermentation, eg. 0.79 or 79%
Y = average attenuation of yeast (eg. US-05 has min 73% max 80%, so Y = 76.5%)
T = Mash temp in CELSIUS.  Eg. for a medium mody mash, Beersmith uses 66.7C. I suspect the range should be kept within 61.9 < T < 71.1.

Using the above values:
ADF = 1.04 x 76.5 - 2.22 x 66.7 + 146 = 77.5%
Therefore
FG = OG x (1-ADF) = 43 x (1-0.775) = 9.7 ---> 10 = 1.010

I'm not sure how this will work for other people's equipment setups - and I'm sorry I'm totally metric - but for me this equation matches anything I plug into Beersmith every time.

What stands out to me is how dependent the ADF is on the mash temperature - (and therefore also FG and ABV) .
Has anyone done any experiments to measure FG for two or more identical beers where ONLY the mash temp was varied?  Or can anyone point me to any papers on this?

One other question, given the significance of mash temp, relates to measuring it.  I run a 3 vessel electric HERMS system and measure the temp of the recirculating water as it comes out of the heat exchanger coil and onto the mash.  I figure during a rest when the temp is stable there is probably not much variance in the temp through the grain BUT as soon as I'm trying to step up to a higher temp it probably matters where the temperature is measured.  Is there a generally accepted best practice for this?
 
http://brulosophy.com/2015/10/12/the-mash-high-vs-low-temperature-exbeeriment-results/ CHEERS

PS. I would want to measure the mash temperature in the kettle;  or  outlet of your kettle,  before the heat source/herms coils.
 
Many thanks twhitaker, Marshall Schott's Brulosophy xBmt is GOLD! (as is all his work).
Marshall brewed a Blonde Ale with the only difference being the nash temperatures;  one at 147F/63.9C and the other at 161F/71.7C.  He got an OG of 1.049 for both and used Wyeast American Ale Yeast #1056 in each.
So of course I've plugged these number straight into my model (derived from Beersmith) with the following results...

Beersmith gives Wyeast 1056's attenuation as 3-77%, so I used 75%...
OG 49, T 63.9, Y 75 --> ADF 82.1, FG 9  (1.009)
OG 49, T 71.7, Y 75 --> ADF 64.8, FG 17 (1.017).
Now although not the same, the difference in OG almost matches Marshall's findings.
Given both results were high, it appears the model is underestimating attenuation - so I played with the Yeast Attenuation.  When I plugged in 82% for both mash temps the results were...  1.005 and 1.014 = exactly what the xBmt found.

CONCLUSIONS:
Firstly, this experiment knocks my doubts about the significance of mash temp on FG (and therefore ADF and ABV) - MASH TEMP MATTERS (to FG) !
Secondly, the attenuation figure needs further investigation.
Thirdly, Marshall's xBmt raises a v interesting question about our ability to perceive the difference in FG (and thus how or how much MASH TEMP DOES MATTER ?)
 
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