Author Topic: ABV prediction way off  (Read 7500 times)

Offline Samo

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ABV prediction way off
« on: June 19, 2018, 09:48:28 PM »
Hey. There's a big difference at the "Est ABV" field amongst BS2 and BS3. It's almost 1% off. The BS2 for me hits the exact ABV at the end of brew, laboratory tested a few times. Why does BS3 calculation fall so far off the previous version?
Reciepe was imported from BS2.
Please assist.

Offline Ck27

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Re: ABV prediction way off
« Reply #1 on: June 19, 2018, 11:20:29 PM »
Hey. There's a big difference at the "Est ABV" field amongst BS2 and BS3. It's almost 1% off. The BS2 for me hits the exact ABV at the end of brew, laboratory tested a few times. Why does BS3 calculation fall so far off the previous version?
Reciepe was imported from BS2.
Please assist.

I noticed that while testing the software, still pissed I didn't get a free upgrade but I may or may not buy BS3 I like 2 more. The only thing 3 offers new that I care about is wine making.


Offline frettfreak

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Re: ABV prediction way off
« Reply #2 on: June 20, 2018, 12:50:02 AM »
Hey. There's a big difference at the "Est ABV" field amongst BS2 and BS3. It's almost 1% off. The BS2 for me hits the exact ABV at the end of brew, laboratory tested a few times. Why does BS3 calculation fall so far off the previous version?
Reciepe was imported from BS2.
Please assist.

I noticed that while testing the software, still pissed I didn't get a free upgrade but I may or may not buy BS3 I like 2 more. The only thing 3 offers new that I care about is wine making.

I have the same thing and was about to post but figured I would tag along in here.  the recipe i have is 2% off. Estimated FG is WAY off. BS2 predicts 1.029 and BS3 is predicting 1.047. Its a huge imperial stout and the difference in FG takes it from a 12% beer to a 10% beer.  Brewed it yesterday so We will see if BS2 is suddenly inaccurate. lol

That being said, BS2 have always been VERY accurate for me, and I brew quite a bit.  Kinda Strange.  Hopefully Brad will see this and respond.  Liking the update for sure though.  Lots of little improvements all over. 

Offline joepjanvh

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Re: ABV prediction way off
« Reply #3 on: June 20, 2018, 03:29:50 AM »
I noticed the same thing.

I've a recipe that I've brewed with Beersmith 2, and exactly hit all the numbers.

Beersmith 2:
OG: 1.077
EFG: 1.013
ABV: 8.5%

Beersmith 3:
OG: 1.077
EFG: 1.002
ABV: 10%

I noticed that Beersmith 3 is taking alcohol tolerance into account.
The yeast used in this recipe is the Fermentis BE-256 with an alcohol tolerence of 10%.
When I adjust the tolerance to a lower value, beersmith 3 is changing the EFG and the ABV accordingly.

Offline Oginme

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Re: ABV prediction way off
« Reply #4 on: June 20, 2018, 05:25:23 AM »
Can one of you export the recipes from both versions of BS as .bsmx files and post them?  I have been running both side by side for some time now and am not seeing the difference in ABV estimate between the two over a whole bunch of recipes covering a range of 3.7% up to 8.9%.   
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Offline Kevin58

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Re: ABV prediction way off
« Reply #5 on: June 20, 2018, 10:47:34 AM »
Make sure your equipment and mash profiles are the same in both. Don't just assume that BS3 imported all of your settings exactly as you had them in BS2.
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Offline BeerSmith

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Re: ABV prediction way off
« Reply #6 on: June 20, 2018, 02:11:29 PM »
Can you send me a few recipes so I can compare them.  Send to beersmith at beersmith.com

Brad
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Offline joepjanvh

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Re: ABV prediction way off
« Reply #7 on: June 22, 2018, 09:30:30 AM »
I've just e-mailed 3 recipes. Exports from beersmith 2 and 3.

ABV per recipe:
              BS2        BS3
Blonde    6.3%      7.8%
Saison    6.4%      7.4%
Tripel      9.6%      10%

Offline joepjanvh

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Re: ABV prediction way off
« Reply #8 on: June 27, 2018, 07:18:17 AM »
I've attached the recipe's to this post, for those interrested in taking a look at the differences.

I've checked possible differences in ingredients, (yeast, malt etc) but this seems to be the same in both versions of BS.
 

Offline needbeer

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Re: ABV prediction way off
« Reply #9 on: July 04, 2018, 04:06:17 AM »
I have had similar trouble when designing a Russian Imperial Stout. I only just realised the problem on brew day. The maximum I can get out of BeerSmith 3 is 10% ABV. I ended up exporting into BeerSmith 2 to finalise the recipe. Anyway, I have made a test recipe that shows 32.3% in BeerSmith 2, but max's out at 10.0% in BeerSmith 3. Here is a screenshot of it maxed out at 10%.



Offline needbeer

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Re: ABV prediction way off
« Reply #10 on: July 04, 2018, 04:11:36 AM »
As a comparison, here is the same recipe in BeerSmith 2.



Offline frettfreak

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Re: ABV prediction way off
« Reply #11 on: July 09, 2018, 10:17:05 AM »
So has there been any work on this issue?  There are several other threads now with what i believe to be the same problem (abv capping out at 10%).  Wonder if @beersmith Brad can give us an update??

Offline Oginme

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Re: ABV prediction way off
« Reply #12 on: July 09, 2018, 11:04:59 AM »
The capping of ABV based upon the maximum alcohol tolerance of the yeast used has been discussed already. (and this was also listed in the release notes for BS3.)

In looked at one of the recipes that joepjanvh posted above (really, if you want help, post the recipes in .bsmx format; screen shots tell us very little about how your process works). 

In his Blonde recipe, he is using step mash with temperature rests at 140F and 158F.  BS2 only counted the first temperature rest within the prime amylase rest zone from 147F to 160F and ignored the other rest temperatures used.  Per Brad's release notes: "Corrected bug in FG estimation that underestimated attenuation of yeast when working with a mash profile that incorporated steps at both low and high mash temps." 

While not perfect, compared to the results estimated versus actual for the Blonde, BS3 was much closer to the actual measured values for its predictions.  Note that the other recipes included also show the same issue:  Multiple rests in the fermentability range yields different results than a model that ignores the multiple rests.

Since this feature has been requested many times in the past, it should not be a surprise that it is included in the latest version.  And listed in the release notes for users to see.
« Last Edit: July 09, 2018, 01:27:39 PM by Oginme »
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Offline sloppybones

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Re: ABV prediction way off
« Reply #13 on: February 13, 2019, 02:55:46 PM »
So, just out of curiosity, why does BeerSmith cap the ABV at 10% WITHOUT a yeast strain in the recipe? I get the tolerance of each strain part. That makes sense. But if I am adding just ingredients before adding yeast, shouldn't I be able to see the potential ABV still?

Offline Oginme

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Re: ABV prediction way off
« Reply #14 on: February 13, 2019, 04:30:35 PM »
It is the default in the software.  Until you specify a yeast, the number is basically meaningless anyway.

The alternative might be to show no attenuation until you enter a yeast. 
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