Confused about Rager and Tinseth Forumlas - Please Help

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ultravista

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I am working on an all grain recipe that calls for 60 IBU. Using Beersmith 1.4, if calculated with Rager, the recipe calls for 3.6 oz of hops. If calculated with Tinseth, the recipe shifts to 4.5 oz of hops - nearly 1 additional ounce.

That 4.5 oz in Tinseth changed back to Rager results in 85.5 IBU.

I am confused as to which calculation I should use. The bottom line is that I need 60 IBU.

Am I missing something?

Doesn't the bittering calculation make or break the recipe and taste?
 
Maybe you should find out which formula the original recipe used for their IBU calculations and go with that. I know that brewing classic styles (Jamil and John's book) calculates all IBU levels using Rager.
 
The only way to assure you have 60 IBU in your finished beer is to brew it and then send it to a lab for analysis, unless you have your own spectrophotometer. That is the only way the pros are able to put an IBU number on their labels.

The various forms of calculations are estimates of a very complicated process that involves far more variables than wort volume, density, hop mass, and duration of boil.

I don't know much about the source or exact usage of each calculation, but IMO the best approach is to pick one and stick with it. Brew a recipe that BeerSmith tells you is XX IBU and compare it to a commercial beer of known IBU somewhere in the range of the recipe to see if you agree with the calculation. Or just tweak the recipe until you get the balance you are looking for.

The beer will certainly be different with 1 oz more hops, but if you stick with one method of calculation, you will be able to adjust in future recipes, and get to know what the IBU value BeerSmith tells you really means in terms of the bitterness you taste.

So give it a shot, HAHB, and maybe relax a bit. I know when I like a beer or don't, but I don't think I can tell the difference between a 60 or 70 IBU beer...:mug:
 
I agree, just pick one and stick with it. Learn what 40 vs 60 IBU's etc. tastes like as calculated by the one you pick. Then let your taste buds guide you in formulating new recipes. Does it really matter what the actual value is? What matters is how it tastes.
 
Doesn't the bittering calculation make or break the recipe and taste?

Not necessarily. Perceived bitterness is much more important than the iso-alpha acid concentration in the beer. Lots of other compounds contribute to actual and perceived bitterness that are not part of the IBU calculation (or measurement in the lab). For example, adding dry hops and sulphates to a beer can make it taste more bitter than it really is.

As for the formulas, recipes often indicate how the IBU estimate was derived. If not, use your best guess based on experience. Using one formula and sticking with it will help you develop a better sense of what certain levels of IBUs taste like on that formula's scale, especially when you also calculate the IBU/OG and IBU/FG ratios.
 
The only problem with just picking one and sticking with it is when you get a recipe from someone else. I've not ventured into recipe building and just use recipes here. They mostly don't share the formula used. You can always PM the OP though. :mug:
 
The only problem with just picking one and sticking with it is when you get a recipe from someone else. I've not ventured into recipe building and just use recipes here. They mostly don't share the formula used. You can always PM the OP though. :mug:

Yeah, but most of those recipes include the grams or ounces for each addition and sometimes even the AA% of the hops that were used. You can enter that into any brewing software and get the IBUs based on your formula that way.
 
Follow the recipe. Be content that IBU calculations are simply approximate and do not necessarily reflect reality.

If you share the recipe you're using, we can lend a bit more help.

When formulating a recipe from scratch, I use Tinseth because it's what I've always done, so I know what to expect. My water profile leads to an increase perceived bitterness. Also, I have a bit of a sweet tooth and usually prefer malty beers. So, I shoot for the lower end of the BJCP recommendation for any given style.
 
I also drive myself crazy with Tinseth vs. Rager, and trying to get into the attitude of saying "F*ck it" and just go with whatever.

I will tell you that I've noticed that the difference between Tinseth and Rager gets bigger when you brew a higher OG wort (say 1.030 vs 1.060) and there is also some difference with higher AA hops.

I like Jamil's book, but he does go by Rager. I'm under the impression that for full-wort boils Tinseth is more accurate, which means converting when doing Jamil's recipes.

I think my new plan to to calculate IBU according to the formulas in Ray Daniels book, pick an utilization efficiency and not even deal with either Rager or Tinseth. Ball-park it as much as I can when doing Jamil's recipes, see where the the perceived bitterness falls and adjust if necessary.
 
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