IBU calculations.....John Palmer vs. Ray Daniels. Round 1 :)

[Elysium]

Hey everyone

You might have seen some of my questions related to IBU calculation....
I have decided to ask a final one in order to determine which one of the tools/calculations I could use to effectively calculate how much hops I need to get to the IBU level I need in my beer.

There are 2 options I can go with...
1, John Palmer's calculation
2, Ray Daniels' calculation from the book “Designing Great Beers”



I will use this hypothetical recipe for the calculation.
9.08 preboil size
8 gallon after-boil size
15 lbs of pale ale malt (36.72 ppg)
1.0576 after-boil gravity
NOTE: I list the preboil size, but I only use the after-boil size in these calculations

/---------------------------------John Palmer----------------------------/
Hop additions:

Using John Palmer''s equiation (IBU = AAU x U x 75 / Vrecipe)...this is what I get:
0.4 oz citra (12%) @ 55= 11 IBU
0.4 oz citra (12%) @ 35= 8.6 IBU
0.25 oz cascade (5.6%) @ 20= 1.9 IBU
0.25 oz cascade (5.6%) @ 5= 0.6 IBU

total IBU: 22.34



/---------------------------------Ray Daniels----------------------------/
Using Ray Daniel''s equiation (IBU=(Woz*U%*A%*7.489)/(Vgal*Cgravity))...this is what I get:
0.4 oz citra (12%) @ 55= 13.96 IBU
0.4 oz citra (12%) @ 35= 12.41 IBU
0.25 oz cascade (5.6%) @ 20= 2.87 IBU
0.25 oz cascade (5.6%) @ 5= 0.9 IBU

total IBU: 30.14





Which one of these calculations gives me the most accurate IBU? Does anyone know?

I actually think that I might have made a mistake somewhere with one of the calculations because of the difference between the 2 IBUs (it is not a lot, but significant)

 

[stpug]

If there are no errors in the calculations then you're best bet is to brew a beer and send a bottle in to a lab to have tested. I think the cost of testing is around $10-15. But, IMO, hop usage varies so much based on process, harvest year, storage, that it's not worth the effort, and instead develop a "feel" for your hops (or rule of thumb) that works for you and your process.

 

[hannibalmdq]

Using this IBU calculator (claims to be from Daniel equations). I get 19.69 for your hop bill and batch info.

http://www.npacc.net/~raw925/tools/IBU.html

 

[Calichusetts]

I think its more personal than anything. Stick with one system and get to the bitterness you like (take note where the IBUs come from, 60 minute additions are very different from late additions.) I have done this and sometimes the IBU ratings are ridiculous, but I know what I will get

 

[Elysium]

I think its more personal than anything. Stick with one system and get to the bitterness you like (take note where the IBUs come from, 60 minute additions are very different from late additions.) I have done this and sometimes the IBU ratings are ridiculous, but I know what I will get

I hear you. I didnt start brewing yesterday though.......but I am a perfectionist. So...I need to find a system, a calculation (or whatever we wanna call it), that is standard and understood by everyone.

I dont know if this makes sense....but this is the idea that made me look into IBU calculations.

 

[Oginme]

There are various IBU calculation methods/models out there. Probably some of the most popular are the Tinseth, Ragar, and Garetz models. As long as you use the calculation and specify which model is used, people can duplicate the recipe. I try to remember to list the IBU calculations in the recipes I publish as using the Tinseth model.

In the end, the models cannot account for your process utilization of the hop oils, so any model is really just an educated guess. As Calichusetts has said, if you select a model and stick with it, balance out the bitterness to your perceived tastes and adjust your target accordingly, you should be OK.

 

[zakleeright]

This discussion all points to something I read a while back, on the topic of "precision" vs. "accuracy".
There are so many variables in what the label on the bag of hops tells you the AA's are, and how many IBU's you can suck out of that bag during your process.
You are using calculations that are very precise (down to 2-4 decimal points maybe), with no way to tell how accurate the result is. At least, none more effective than what is the bottom line anyway, which is "do you like how it tastes".
So, it seems that the best suggestions above point to "pick any method and stick with it", and adjust future batches based on current results. A better way to "get your OCD on" is to track your brew session and process, (ingredients, volumes, temps, timing, SG, pH, etc) so that you continuously learn how certain actions yield certain results. as a bonus, everything you do becomes more accurate, which means that any precision you use has more meaning.

 

[Elysium]

This discussion all points to something I read a while back, on the topic of "precision" vs. "accuracy".
There are so many variables in what the label on the bag of hops tells you the AA's are, and how many IBU's you can suck out of that bag during your process.
You are using calculations that are very precise (down to 2-4 decimal points maybe), with no way to tell how accurate the result is. At least, none more effective than what is the bottom line anyway, which is "do you like how it tastes".
So, it seems that the best suggestions above point to "pick any method and stick with it", and adjust future batches based on current results. A better way to "get your OCD on" is to track your brew session and process, (ingredients, volumes, temps, timing, SG, pH, etc) so that you continuously learn how certain actions yield certain results. as a bonus, everything you do becomes more accurate, which means that any precision you use has more meaning.

I totally agree with you and would do so gladly....but not when one calculation gives me a close to 20 IBU and another one gives me 30 something.
It means that my calculation is totally incorrect (one of them at least)....meaning it is pointless to worry about anything unless I have control over all the aspects of my brewing.

I understand that no matter what I do, I get beer......but that is not my goal here. I'd like to brew really good beer and I think I need to reach the end of the learning curve to do so.

 

[hannibalmdq]

I totally agree with you and would do so gladly....but not when one calculation gives me a close to 20 IBU and another one gives me 30 something.
It means that my calculation is totally incorrect (one of them at least)....meaning it is pointless to worry about anything unless I have control over all the aspects of my brewing.

Umm. I could've punched in the numbers wrong...but I don't think the Daneils is actually 30.

Using this IBU calculator (claims to be from Daniel equations). I get 19.69 for your hop bill and batch info.

http://www.npacc.net/~raw925/tools/IBU.html

 

[WayFrae]

Has anyone ever used this lab to test IBU?

 

[VikingChrisColby]

There isn't one best hop utilization curve (slash way to calculate IBUs), only the method that will give you the best results given your brewery, water, techniques, etc. Pick a method that seems reasonable and stick with it. Alternately, get a couple of your beers tested and see which method give results closest to your actual results.

http://beerandwinejournal.com/most-accurate-curve/



Chris Colby
Editor
http://beerandwinejournal.com

 

[zakleeright]

right on Elysium...if it helps I've used both Daniels and Beersmith (currently beersmith...easier) and the results have always been as expected. and especially agree with your sentiment of "great beer...not good beer"...thus the other metrics suggested as having far greater effect on the path toward your goal. meanwhile, here's to enjoying the journey!

 

[Oginme]

Having an absolutely accurate calculated number does not make a beer become a great beer. Regardless of the estimated IBU number, your consistency in process, type and quality of raw materials, and attention to details will enable you to produce the same recipe time after time. The calculation of IBU is only a guide to help you steer your recipe towards consistency in the design, the rest is up to you. A calculated figure cannot predict your process, your handling and storage of the hops, or a vast number of variables involved in the brewing.

In the end, the amount of bitterness is a perception of the drinker. Pick a model, design your recipe around it, make adjustments in your recipe to get the amount of bitterness you want by taste and flavor. Then adjust your targets during design to match your observations. If you design to target an IBU of 40 and you feel it is not bitter enough, target 50 next time. Repeat until you are happy with your outcome and then use that offset to make future recipes.

Your alternative is to have your hops tested for alpha acids every time you brew and with each batch you buy, run a series of hop addition brews based upon amount of addition and time of addition, under different starting and finishing gravities, and have each one sent out to a lab for IBU testing and build your own specific model.

As an engineer, I understand the passion for being accurate, but really your goal should be a passion for being consistent and then you should find an improvement in your outcome.

 

[Elysium]

Having an absolutely accurate calculated number does not make a beer become a great beer.

I am here because I have been reading/planning/asking/documenting everything that is related to my brewing process for more than a year.

This (IBU) is just one bit of the puzzle I have been working on.
All what you have mentioned above form a part of the plan too and I must say they have been ticked off the list.

Then again....this is something that I wanna look into and make sure I know it 100% well and right too.