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Old 02-23-2011, 12:31 PM   #1
xxHelderxx
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Default IBU Theory

Hi Everyone,

I've done a search but can't find any threads dedicated to IBU theory. I know it can get a bit technical and dense but I'd like to learn some things regarding how many IBUs I can actually get into a beer (I've heard the max is ~100) and what any additional hops contribute to the flavor profile of a beer. I'm formulating a recipe and want to know at which point I'm just wasting money by adding hops. Here is a sample hops schedule for reference:

.5oz Columbus (FWH) @14.5%
1oz Columbus 60 min @14.5%
1oz Nuggest 60 min @ 12.2%
.5oz Columbus 45 min @ 14.5%
1 oz Nuggest 45 min @12.2%
1oz Centennial 30 min @9.7%
1oz Williamette 10 min @ 4.8%
.5oz Centennial 10 min @9.7%
1oz Williamette 13 days dry hop @4.8%
.5oz Centennial 13 days dry hop @9.7%

My BrewPal app tells me that should be 164 IBUs but I know there are several caveats to that.

Can anyone help me to understand what's actually going on here in terms of IBUs?

Also, I've read about additions longer than 20 mins contributing little to no flavor, so is there also room in this schedule for some movement in order to be more efficient?

Thanks!!


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Old 02-23-2011, 12:42 PM   #2
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For really bitter beers I tend to aim for ~150 IBUs, even though the measured value rarely if ever goes over 100. You are probably pretty close to saturating the beer with bitterness, but you could add plenty more aromatics. I would shift the 30/45 min additions up to 60 and down to 0 to get the most out of them. I'd also double the dry hop if you want an agressive hop nose.


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Old 02-23-2011, 12:45 PM   #3
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For bitterness, there are several formulas out there but Tinseth is generally considered to be best of breed. That said, it is several years old and a lot of the thinking has changed since then. The formula is described here. I think the general consensus is that you start getting sharply declining returns past 100 IBU, but I don't know of any real research on the matter.

As far as flavor goes, this idea of "early=bitterness, late=flavor/aroma" is sometimes overstated. It is certainly true that longer boil hops will contribute more bitterness and shorter boil hops will tend to be more aromatic, but it isn't really accurate to say that additions longer than 20 minutes add no flavor. For starters, bitter is a flavor, right? But even if you mean something more specific by "flavor" (i.e., variety-specific character), different types of bittering hops will lend different characteristics to the beer.

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Old 02-23-2011, 01:48 PM   #4
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Thanks OldSock and Malfet.

Having read what you both posted, I'm still a little curious about my hop schedule above. Is there any way for me to look at this and understand if I'm essentially using more than need be for the resulting IBUs?
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Old 02-23-2011, 02:02 PM   #5
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I guess I'm not sure I understand your question. None of your hops is going to "waste" if that is what you mean. When trying to brew a beer of very high IBU, it ends up being a bit inefficient just because of the diminishing return factor. If you take any of those hops out, you'll end up with a different, less bitter profile. It is not as though you get full extraction of hops up to 100 IBU and then a complete stop past that, at least not according to my understanding of isomerization and diffusion.

If you want more bitterness from the same amount of hops, you can do what oldsock suggests and push some of your middle additions earlier. If you want more hop nose, you can push some of your late additions to whirlpool (or even add more then).
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Old 02-23-2011, 02:08 PM   #6
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Some reading material on the subject, much of which is beyond my scant chemistry knowledge.

http://www.hopresearchcouncil.org/re...chemistry.html
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Old 02-23-2011, 02:41 PM   #7
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Thanks again Malfet- you answered my question which was more regarding hop timing to achieve more bitterness.

Samc thanks for that link! I'm really curious about this subject.

Thanks to all!
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Old 02-23-2011, 03:08 PM   #8
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I wondered about a similar thing when I started thinking about formulating some IIPAs. I looked at a bunch of recipes and pretty much came to the conclusion that so long as you have about 2oz of high alpha hops (like 14% and up) at the beginning of your boil, you'll approach maximum bitterness. Couple that with some hefty late additions and you'll almost certainly hit it.

I've definitely found that I get more bitterness (or apparent bitterness if that's a thing) when I do some sort of continuous hopping. For a barleywine I intended to age a long time, I did one 60 min addition, and then a bunch of half oz additions every 5 minutes from 30 minutes onward.

So I'd say that anything more than 2-3oz for your bittering addition is waste. Extra hops should be used for late additions.
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Old 02-23-2011, 04:09 PM   #9
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Thanks Kanzimonson- this is basically the anectodtal info I was looking for. I just wasn't sure if there were any hard and fast kind of formulations for understanding the IBU or as you said "perceived" bitterness drop off of hops that would bring you in excess of 100 IBU.

I think it will end up being more of a trial and error exercise.
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Old 02-23-2011, 05:18 PM   #10
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The human palate supposedly can't detect any past 100 IBU, but those hops still add flavor and changing the additions will affect the profile of the beer--even if it stays above 100 IBU.



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