IBUs vs Actual Bitterness

I have been making a few black IPAs recently and have found that the the IBUs I get out of my calculations don't match the actual bitterness of the beer. I understand that a stronger beer could appear less bitter even with the same IBUs but then why do these IBU calculators figure in the original gravity.

Also I've heard your pallet taste over 120 IBUs or some where close to that. My black IPA is around 107 IBUs and has and O.G. of 1.061 F.G 1.016 and is not extremely bitter.

Last of all could the fact that home brewed beer aren't filtered effect the bitterness, seeing as how they are not as crisp as a filtered beer.

I really feel like for the strength of the beer and the IBUs it should be more bitter than it is. If you have any suggestions for why this might happen I'd love to hear them.

Thanks,
Dan

IBUs are a measurement of the amount of bitterness in a beer based on hazy algorithms based on AAU%, time spent in the boil and other factors. A calculated IBU may or may not be accurate due to those factors, plus storage and other factors. In addition, residual sweetness (from low attenuation) or just strong malt character will render some of those IBUs essentially irrelevant. This is rather like using a balance of lemon juice and sugar mixed with water to have a lemonade that satisfies your taste. A beer with very strong malt character will need a larger amount of IBU just to balance the malt. I hope that helps.

Thanks, that makes sense. Do think with it having a final gravity of only 1.016 and ABV of 5.9% that that would be enough to effect it that much? Although its a darker beer its not extremely malty, dark, or high gravity. Thanks Alot

The problem with approximating IBUs with formulas is that there is a utilization factor that is largely unknown. It depends on a whole host of factors, and varies depends upon the system.

For all of the discussion on Rager vs. Tinseth vs. ?....at that end of the day all of them are nothing more than best guesses...

Not that I have means to use some thing like a brewery but out of pure curiosity does any one know how the breweries get theirs so accurate?... I'm assuming they are accurate.

fromhereon said:

Not that I have means to use some thing like a brewery but out of pure curiosity does any one know how the breweries get theirs so accurate?... I'm assuming they are accurate.

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They use laboratory instruments to measure them. Like spectromometers, for example.

Thanks for all your help. Its all very helpful. Unfortunately I am still a little confused how the bitterness could be as low as it is. I've tried submerging the hops better, boiling harder using different IBU calculators, different batches of hops to make sure the weren't old. Either way these will help.
Thanks

fromhereon said:

Thanks for all your help. Its all very helpful. Unfortunately I am still a little confused how the bitterness could be as low as it is. I've tried submerging the hops better, boiling harder using different IBU calculators, different batches of hops to make sure the weren't old. Either way these will help.
Thanks

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Can you post a typical recipe, along with technique, for a batch that you're disappointed in? Maybe we could point out what we see. For an idea, I always use Tinseth IBU scale. It may not be what some breweries use, but I know what "60 IBUS" tastes like to me with the scale I use.

Ok I'm not sure if you wanted the same batch but this is the black IPA:

15 lb American 2 row
1 lb Chocolate
1 lb Caramel
.5 lb Black (Debittered)

1 oz Simicoe 12.7 aa for 90 min (total)
1 oz Amarillo 11.2 aa for 90 min (total)
1 oz Simicoe 12.7 aa for 10 min (total)
1 oz Amarillo 11.2 aa for 10 min (total)
2 oz Amarillo (Dry Hopped)

White Labs California Ale Yeast

O.G: 1.061
F.G: 1.016
ABV 5.91%
IBUs: 107.1

We mashed using a single infusion mash for 60 minutes. Boiled with a decent rolling boil and completely submerged the hops.

The beer tasted great but just wasn't very bitter.

Ok, a couple more questions! With that grain bill, I would have got 1.090. Did you really get 1.061, or was this a 10 gallon batch?

If it's a 10 gallon batch, I come up with 43 IBUs. For a 5 gallon batch, I come up with 62. I didn't count the 10 minute hops at all, but maybe they contribute a bit of IBUs, but nothing signicant.

No that's a 5 gallon batch, we collected 6.5... 1.090? Really? I didn't think the efficiency was that bad. Although now that I look at it for 15 lbs that' not very high. Although I just bought an auto sparge that really made a difference, uping it to 1.075 but pre boil it was 1.04 which seems to be 42% so yea thats not great. The rest temperature seems to be around 150 to 148. How could I be off that bad?

Yeah, something is off. I just brewed a beer with a similar grain bill (17.5lbs) and hit 1.083.

How are you adding the hops? You say you submerged them, but they are thrown in loose or contained somehow?

In my first IPA, I used muslin bags and crammed too many pellet hops into them. I got terrible utilization and it didn't even taste like an IPA. Once I built a hop spider, those hops were free to swim around in the wort...big change.

I'm using the muslin bags, but 2 oz of leaf hops in one of those bags doesn't seem like a tight fit.

I'm wondering if my calculations for the IBUs could be off if my gravity calculations are off. How could I only be getting 42% efficiency when the mash temperature seems great. Unless my ph was way off, which I haven't checked, but I'm using bottled spring water. And I tested my hydrometer in water and got a 1.000 or 1.001

http://www.realbeer.com/spencer/hop-analysis.html

That's how to know for sure. Some breweries might send their beer off once and then rely on that as a benchmark measurement. That way based on their AA% contentof different hops they can adjust hops accordingly.

In addition to what everyone else has said, it is important to note that IBUs are a measurement of isomerized alpha acids (and some beta acids), not perceived bitterness. This is related to, but not the same as, how bitter a beer tastes. The OG parameter in most of the formulas is an attempt to compensate for lower hop utilization in big beers, though it is not clear how exactly that works.

Those little muslin bags will cramp your hop utilization significantly, too.

Is there a better way than just throwing the hops in and letting them float around freely to get a better extraction rate

fromhereon said:

Is there a better way than just throwing the hops in and letting them float around freely to get a better extraction rate

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Some people use big paint strainer bags; others just use more hops. I've always just let them float around, so I can't really comment on either method.

Main thing is, as others have said, don't count on those formulas for much except to compare variants of the same recipe. 100 IBU in a RIS is manageable, but would be completely undrinkable in a 1.030 light lager.

A good way to estimate the bitterness of a brew is the BU:GU ratio. But, as this article points out, that is a little misleading. As MalFet points out, the OG and FG of your brew are just as important in estimating the bitterness as IBU's.

What are you using to get these IBUs.

Yooper said:

For a 5 gallon batch, I come up with 62. I didn't count the 10 minute hops at all, but maybe they contribute a bit of IBUs, but nothing signicant.

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What are you using to get these IBUs.

fromhereon said:

Is there a better way than just throwing the hops in and letting them float around freely to get a better extraction rate

Click to expand...

There's really no reason to use a hop bag, especially if you are trying to get one of those crazy hoppy beers. (107 IBUs? Really? Are you mad at your tongue or something?) Better extraction will come from finer particle size and better convection. If you are using T9 pellets you probably can't do much better than dumping them straight into the boil. Whole hops might be improved by grinding or something like that.

I just ran the same recipe through Beer Tools Pro..
Without the 10 minute hops I'm pretty close to what Yooper states, although I adjusted my final volume to match the 6.5 you say you collected.
With the 10 minute hops it goes up quite a bit to 96 IBU.
It doesn't look like you're too far off in your calculations.