Promash vs Beersmith IBU calculations

[corkybstewart]

Here's the deal. I brewed a saison (10 gallon)this weekend and entered the data in both programs. The hops used were 3 oz BKG(5.4 AA) for 60 minutes, and 2 oz Saaz 3.5 for 20 minutes. Beersmith calculates IBU's at 25, Promash at 39.5. Beersmith doesn't add any IBU for the Saaz at 20 minutes, Promash does but not much. Anybody know why the calculations are so different.

[denver brewhoo]

I use beertools--I'm one of the few I gather--and they give you a choice between about 6 algorhythms for IBU calculation. One of these days I'm gonna run the same recipe through all six....I use their own proprietary one, and I've made some bitter bitter beers that only came in around 80, making me think that these might have been around 100 on somebody else's algorythm

[denver brewhoo]

hmmm--shows what I know--just ran your hops additions on a 1.065 saison recipe of mine and got the following results on all the options beertools gives you--

Beertools---40.6
Basic---------35.6
Rager--------41.8
Garetz-------29.0
Mosher------32.5
Tinseth------34.0
Daniels------42.0

I don't know which ones Beersmith and Promash use-- Garetz and Rager, respectively, maybe?

Note--beertools for some reason gives you IBUs based on 1.054 gravity wort. So it didn't make any changes even though my recipe was for 1.065 wort....maybe Promash does?

[corkybstewart]

My OG was 1.092, maybe Promash accounts for that, Beersmith doesn't. But Beersmith also didn't add any IBU for the 20 minute addition. I know it doesn't add much, but a little bit at least.

[denver brewhoo]

yeah that's weird...when I ran the beertools one it was like 36.2 for the 60 min addition and 3.62 for the 20 min addition...wait a minute, that doesn't add up to 40.6....well, something like 10% of the total IBU were in the 20 minute addition.

I wouldn't think much of the accuracy of a program that gave you NO bitterness for a 20 minute additon of even low AA hops like those Saaz.....

[danno]

Originally posted by denver brewhoo
Note--beertools for some reason gives you IBUs based on 1.054 gravity wort. So it didn't make any changes even though my recipe was for 1.065 wort....maybe Promash does? hop utilization definitely changes in relation to gravity, so that's a reason right there to skip beertools, unless all your batches are going to be 1.054...

when I plug this into ProMash, at 1.092 I get 34.3 IBU's, and at 1.053 I get 41.0 IBU's.

dunno Corky, maybe your settings are hosed up?

[denver brewhoo]

"so that's a reason right there to skip beertools, unless all your batches are going to be 1.054..."


well, hard to argue with that, except I think that what the discussion so far establishes is that differences in formula make all of this speculative and I find beertools quicker and intuitive to use...the times I demo'ed Promash it seemed to demand answers I wanted to skip over.....no doubt I'm just too stupid but I read a long dialogue on Northern Brewer the other day where somebody apparently affiliated with Promash was explaining some of the workings....and the explanation and the ongoing Q & A seemed to support my original impression, that for me at least it's a little unwieldy...

[dparsons]

Promash also offers a choice of calculation model
Rager
Garetz
Tinseth
Generic

I notice there is quite a spread between the different models. Anybody have an idea if these have been checked? Whichi is accurate?

[dparsons]

Ask and you shall receive. A short article on 3 of the hop IBU models for anyone who is interested.

http://www.valhallabrewing.com/dboard/dbnewsla/Dn1809a.PDF

[Mad Scientist]

I know that beersmith IBU calculations change with gravity, I use beersmith, and it does adjust. I have not looked to see if it gives a choice of IBU formula, but I will, if someone does not beat me to it.

[daveh]

I have beersmith as well, and it gives you three different options for calculating IBU:

1. Tinseth (default)
2. Rager
3. Garetz

So which should we be using?

-dave

[danno]

Originally posted by denver brewhoo
"so that's a reason right there to skip beertools, unless all your batches are going to be 1.054..."


well, hard to argue with that, except I think that what the discussion so far establishes is that differences in formula make all of this speculative and I find beertools quicker and intuitive to use...the times I demo'ed Promash it seemed to demand answers I wanted to skip over.....no doubt I'm just too stupid but I read a long dialogue on Northern Brewer the other day where somebody apparently affiliated with Promash was explaining some of the workings....and the explanation and the ongoing Q & A seemed to support my original impression, that for me at least it's a little unwieldy... i too thought it was unwieldly when I first demo'd it, but the more you play around with it, and see what the variations do for your brewing, the more impressive it becomes.

I really shouldn't be ragging on beertools since i've never used it, but if the quote I initially quoted proves to be true, that would seem to be a rather major software failing. promash will scale your IBU's (and everything else, for that matter) as you adjust your ingredients...

[corkybstewart]

I'm sure I haven't entered all the data requested or the questions don't seem to apply to my situation, and I could easily see a fe points difference between any of them. For instance, my mash on this batch was continuously heating from around 90F to 150F over 1.5 hours. Neither program had that as an option, as far as I could find, so I just picked a 3 step mash. It's not what I did but it's the closest.
I noticed this on my Imperial stout also. The IBU's on Promash were 83, but only 56 on Beersmith. I just finished a glass of it and I'd say it tastes more like a 56 than an 83, but it really just tastes like alcohol this afternoon. My RIS had 11 oz of hops, 5 for 60 minutes so I can't imagine only getting 56 IBU's.

[Mad Scientist]

yes, but the incredible gravity of the stout will seriously affect the utilization.

[corkybstewart]

That may be true, but I would hope that the software would compensate for it. I'm not one of these brewers who lives and dies by the numbers. I want a beer I can drink and enjoy. As I posted on another thread, I develop my recipe in the garage based on what I have on hand, then after brewing I enter the data into Beersmith and Promash to see what kind of numbers they come up with, instead of putting numbers into the software and then adjusting my recipe accordingly. Seat of the pants, brothers, it's the only way to homebrew.

[danno]

Originally posted by corkybstewart
Seat of the pants, brothers, it's the only way to homebrew. I know we've beaten this horse to death before, but as the resident judge, I can tell you that stylistically accurate beers beat better tasting, but inaccurate beers in contests all the time. so, if you're a wanna-be contest whore, like me, you need to pay attention to the numbers... :cool:

[corkybstewart]

I have no desire to compete, I brew for myself, my wife and my friends. That attitude goes for my whole lifestyle. I hate having to conform to somebody else's rules and regulations just because they think they're right. I wear shorts and aloha shirts year round, and I work in a very conservative industry. Now that I work in an office I do wear shoes instead of sandals, but that's my only concession. Maybe that's why I love the Belgian brewing spirit-no rules.
We've had this discussion before Danno, but if I had ever thought that the goal of homebrewing was to please judges I never would have bothered.
I am my own personal judge and there is none harsher. But I brew only for pleasure, mine and my beer drinking compadres, and I only use the software to record what I've brewed, not to conform to someone else's guidlines.
The whole point of the thread was to see if one program is more "correct"than the other.

[Mad Scientist]

Corky, you forgot the long hair....something else that does not hold well in our (I am in it on the far side of things) industry.

I agree with you that I am not a contest whore,, and have never enetered a beer in one, but I do my recipes ahead of time, so that I know what I am making and the goal I am shooting for....

[corkybstewart]

I know what I want each batch to taste like, and I have a pretty good feel for how bitter my beer will be, I use pretty simple and consistent hopping schedules. And I do look at my recipes before I brew to see if I should adjust something I didn't like about the last batch. That's one reason I enter them into the software, but I don't let the software dictate. I see these recipes that call for 1.23 oz hops A and you know the author was letting the software adjust his hops for a certain target number. That's just silly.

[denver brewhoo]

Originally posted by corkybstewart
I see these recipes that call for 1.23 oz hops A and you know the author was letting the software adjust his hops for a certain target number. That's just silly.

man, truer words were never spoke. Sometimes I rib these dudes---"I think I put .06 oz too many of them magnums in the 60 min addition, f***ed the whole thing up..."

I am definitely a whole numbers guy when it comes to our hobby.

I do run a beertools sheet before I head to the store though. But it takes less than a minute, and then I always seat-of-the-pants it when I get there anyway.

The beers I like tend to be stylistically fairly wide open--there's a lot of freedom, for example, in BJCP Section 8, "English Pale Ales and Bitter"--so my stuff can be free association AND within guidelines, usually...

[daveh]

Slightly back on topic,

I fired up promash and it seems that it's default hops algorithm is Rager....so, that appears to be an obvious reason why the two programs come out differently.

It would be interesting to redo the recipe calculations but first make sure they are both set to the same algorithm. I suppose it could be done with any recipe. If no one beats me to it, I'll give it a try if I have the time later...

-dave

[BitterRat]

The whole point of the thread was to see if one program is more "correct"than the other.
Thats it right there! IMO, we can't say this software or that software is more correct, unless someone takes the beer to a lab and tests it to find out exactly how many IBU it has, then we could tell which is more correct.
With that said, I have seen on another forum( I can't remember which one though) that Tinseth setting in Promash is more accurate for All Grain brewing than the others. Not sure why though, anyway, I think daveh is correct that the Rager setting is the default.

[daveh]

But then, does Tinseth (Promash) = Tinseth (Beersmith)??

-dave

[dparsons]

Yes, Rager is the default in Promash. The document I reference earlier experessed the opinion that Tinseth is probably a better model, using some qualitative arguments that made sense - no stair stepping of IBU contributions, not maxing out at 90 minutes. Rager is the oldest model and apparently people have thought it overpredicts some. None of this is as good as comparing to actual IBU measurements for differing conditions, but I don't think that exists. Probably the best thing these models do is help us predict how a beer is going to taste. To that end being familiar with a model is more important than its accuracy.