TINSETH v. RAGER

Ok planning a simple SMaSH pale ale with Maris or 2-row and Azacca hops wanted to try a shortened boil @45min maybe less and all late hopping like this:
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Problem is according to Brewer's Friend I get this: (see the IBU's part)
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On normal 60min bittered batches these are usually pretty close but I guess they vary greatly on the ibus from late hopping just wondering what everyone uses especially in this case for late hopping. While 42 IBUS is pushing the high end of what I want 28 is definitely too low hoping I'm somewhere in the middle as far as perception anyway. Probably been discussed/answered/beaten like a dead horse somewhere but didn't see it.

Tinsith, Rager, Mosher, Noonan, Daniels, Garetz, etc... are merely empirical math models, and none of them are going to be correct in modeling your particular brewing methods as to IBU's. Your actual IBU's may vary away from these models by as much as 33% to perhaps in extreme cases 50%, or they may be close. Variance (to whatever degree) to the down side appears to be well more common than to the upside.

The best you can do (this side of actual lab analysis) is find the empirical model you can feel most comforted by, and stick with it.

Do you really know the age and storage history of your hops (particularly before they fell into your hands), and their actual lab measured alpha acids concentration? And on top of this, Tinsith never once tested hop pellets (and likely neither did any of the rest), so that merely tosses yet another unknown into the mix. All of the speculation that pellets add 10% or more IBU's is merely that, speculation.

In a recent test whereby several people brewed identical batches using their home equipment and then lab analysis was used to actually measure their IBU's, the guy who had the most abysmal cooling efficiency (and it was awful) was the guy who actually came closest to hitting the initially expected IBU's based upon the Tinsith model. Some of the others were quite low.

https://www.experimentalbrew.com/podcast/episode-32-ibu-lie

https://www.experimentalbrew.com/podcast/episode-33-bitter-truth

Silver_Is_Money said:

Tinsith, Rager, Mosher, Noonan, Daniels, Garetz, etc... are merely empirical math models, and none of them are going to be correct in modeling your particular brewing methods as to IBU's. Your actual IBU's may vary away from these models by as much as 33% to perhaps in extreme cases 50%, or they may be close. Variance (to whatever degree) to the down side appears to be well more common than to the upside.

The best you can do (this side of actual lab analysis) is find the empirical model you can feel most comforted by, and stick with it.

Do you really know the age and storage history of your hops (particularly before they fell into your hands), and their actual lab measured alpha acids concentration? And on top of this, Tinsith never once tested hop pellets (and likely neither did any of the rest), so that merely tosses yet another unknown into the mix. All of the speculation that pellets add 10% or more IBU's is merely that, speculation.

In a recent test whereby several people brewed identical batches using their home equipment and then lab analysis was used to actually measure their IBU's, the guy who had the most abysmal cooling efficiency (and it was awful) was the guy who actually came closest to hitting the lab results. Some of the others were quite low.

https://www.experimentalbrew.com/podcast/episode-32-ibu-lie

https://www.experimentalbrew.com/podcast/episode-33-bitter-truth

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How this all so true. All IBU calculations are a SWAG (Scientific Wild Arsed Guess). I developed a custom Excel spreadsheet to supplement BeerSmith and was playing around with IBU calculation methods last month. While trying to understand the underlying math of brewing and learn more about the actual process, I was stunned at how hard it was to calculate IBUs.

I have a tab for hops and attempt calculate the actual IBUs based on their age, storage and initial reported Alpha %. The number of factors influencing IBUs was also surprising. It took me a few days of research and number crunching to come up with something reasonable. I ran a three different use cases against the IBU tools in BeerSmith, Brewer's Friend and another site that let you select different models. My numbers came out fairly close, but YMMV.

After looking at numerous IBU formulas, I distilled it down to this:
= (1.65*0.000125^(EstOG-1))*((1-2.72^(-0.04*F27))/4.5)
Where EstOG is the estimated Original Gravity and F27 happens to be the cell used for the time in minutes that the wort temp is over 180 F and has hops in it. If using pellets, multiply the result by 1.1.

As the Tinseth model has a couple of parameters the scientifically inclined is tempted to take a bunch of measured beers, put their data into the model and find the values of the parameters that minimizes the rmse between the measured and predicted values over this ensemble. I've done that and the variances are still all over the place.

If the guy in the test who came the closest to matching the Tinseth math model results had the worst wort cooling time of the bunch (by far), then perhaps Tinseth likewise had very poor wort cooling efficiency if measured by today's standards? His results (leading to the creation of his math model) could only be as good as his equipment....

But then a small handful of people brewing ostensibly the identical batch, sans for using their own equipment and methods, does not a good scientific study make. This procedure (or rather procedure variance) would need to be replicated many times over to gain any level of statistical significance.

But I'm willing to accept that the variance is going to be great regardless of the level of control.

Using other analytical methods, I've found that the Tinseth method is more accurate at predicting iso-alpha concentration in post-boiled wort. So that should direct you to prefer that method. The problem I find is that many brewers use the Rager method to predict their bittering and IBU level reported in their recipes. If you target those Rager-derived IBU levels and use the Tinseth method to determine the hop additions for your brew, I've found that you likely have a more bitter than intended result. For that reason, I just stick with the Rager method for calculating my hop additions.

I recall Jamil Z recommending that you should just pick a bittering method and learn to live with it.

Yep, pick a method. Learn what "20 IBUs" taste like on your system. Learn what "40 IBUs" tastes like. Etc. And live with. Repeatability and being able to identify what your recipe is going to give the final beer is what you're after.

I just listened to an interview with Tinseth on Experimental Brewing Podcast, where he stated that his formula was written only for whole cone hops and any use of his formula with pellets would probably be way off. Denny and Drew had the same recommendation as Jamil Z.

Is there any lab verified proof that (weight for weight, variety for variety) pellets deliver on average more IBU's than leaf?

I'm sure there is analytical proof that pellets deliver more IBUs per weight than whole hops, but I don't have that handy. When you think about it, pellet hops are well macerated (chewed up) and more of their lupulin glands are ruptured and contributing than they are in whole hops.

If an analogy can be made between hops and most other spices, most would likely agree that fresh spices lend a more profound flavor impact than do dried out ground spices.

Silver_Is_Money said:

If an analogy can be made between hops and most other spices, most would likely agree that fresh spices lend a more profound flavor impact than do dried out ground spices.

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Agreed. The problem is that whole hops do age more rapidly since they have higher surface area and have higher potential for oxygen contact. Pellet hops do age more slowly and can be expected to retain more of their freshness for a longer time.

Cool thanks for the replies I've been pretty happy with Tinseth for the regular 60 min bittering just wasn't sure if rager was more accurate for late bittering guess I'll just brew as is and have to adjust from there. Guess that's the point of trying something new anyway.

The interesting thing in that experiment was that the deviation from the calculated IBUs increased as the IBUs and gravity increased (from PA, to IPA, to IIPA).

I hope there is a chance for us to do that experiment again, especially since I think we have found some potential impact variables like boil vigor, chilling times, whirlpool temp, etc.

Tinseth's formula is as close as anything gets... and it's plus or minus about 30-40%. Still, I recommend Tinseth, because it's as close as anything gets.

What do you guys use for flameout/hopstand/whirlpool/>175°F additions? I use a spreadsheet anymore instead of software. I treat "flameout" hops as 5 minute boils for calculating IBUs.

Weezy said:

What do you guys use for flameout/hopstand/whirlpool/>175°F additions? I use a spreadsheet anymore instead of software. I treat "flameout" hops as 5 minute boils for calculating IBUs.

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Determine the time the hops are above about 120 F. Treat the flameout/hopstand/whirlpool hop additions as if they had been boiled for half the time. For instance, a 30-minute whirlpool will give you approximately the same IBUs as if you had boiled the same hops for 15 minutes. This can be very significant depending on how long the hops stay warm, or not very significant at all if you chill down immediately.

This leads me to ask: At what juncture (as a percentage) can one typically notice a change in the IBU's?

Can you readily and reliably notice the difference between 20 IBU's and 30 IBU's (50% more)?
Can you readily and reliably notice the difference between 30 IBU's and 40 IBU's (33% more)?
Can you readily and reliably notice the difference between 60 IBU's and 70 IBU's (16.7% more)?

My first guess is that the first would be relatively easy, the second would be tough, and the last would be unlikely.

dmtaylor said:

Determine the time the hops are above about 120 F. Treat the flameout/hopstand/whirlpool hop additions as if they had been boiled for half the time. For instance, a 30-minute whirlpool will give you approximately the same IBUs as if you had boiled the same hops for 15 minutes. This can be very significant depending on how long the hops stay warm, or not very significant at all if you chill down immediately.

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I thought isomerization was limited to 175+?

Silver_Is_Money said:

This leads me to ask: At what juncture (as a percentage) can one typically notice a change in the IBU's?

Can you readily and reliably notice the difference between 20 IBU's and 30 IBU's (50% more)?
Can you readily and reliably notice the difference between 30 IBU's and 40 IBU's (33% more)?
Can you readily and reliably notice the difference between 60 IBU's and 70 IBU's (16.7% more)?

My first guess is that the first would be relatively easy, the second would be tough, and the last would be unlikely.

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I agree 100% based on my taste buds.

Weezy said:

I thought isomerization was limited to 175+?

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False. Isomerization continues into the low 100s F but just at a very much slower pace. I'm not sure the exact cutoff, but I believe it may be between about 110 to 130 F, in that ballpark. At like 140-175 F, it's still kicking pretty fast.

Silver_Is_Money said:

This leads me to ask: At what juncture (as a percentage) can one typically notice a change in the IBU's?

Can you readily and reliably notice the difference between 20 IBU's and 30 IBU's (50% more)?
Can you readily and reliably notice the difference between 30 IBU's and 40 IBU's (33% more)?
Can you readily and reliably notice the difference between 60 IBU's and 70 IBU's (16.7% more)?

My first guess is that the first would be relatively easy, the second would be tough, and the last would be unlikely.

Click to expand...

I've heard it said that the human palate detects IBUs in packets of 3-4 IBUs each. So, you can tell the difference between like 20 & 25 IBUs, or 65 & 70 IBUs, but not 20 & 22 IBUs or 65 & 67 IBUs. This may require careful side-by-side comparison training and experience, but it is certainly possible -- there are professional tasters out there who can do this, and it does not require the individual to be a "supertaster" either -- the average palate can be trained to do this.

dmtaylor said:

False. Isomerization continues into the low 100s F but just at a very much slower pace.

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Dave, that is not what the laboratory data from Shellhammer and Malewicki found. The activation energy needed to isomerize alpha acids is equivalent to a wort temperature of 185F. Therefore in the typical post-boil whirlpool, the wort will continue to become more bitter since the wort temp is still above 185F during that stand.

mabrungard said:

Dave, that is not what the laboratory data from Shellhammer and Malewicki found. The activation energy needed to isomerize alpha acids is equivalent to a wort temperature of 185F. Therefore in the typical post-boil whirlpool, the wort will continue to become more bitter since the wort temp is still above 185F during that stand.

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Seriously? Thanks -- I might be ignorant (seriously) but this is the first I've heard of this. I'm pretty dang sure I've heard someplace of experiments run with lower temperatures that did in fact find higher IBUs from lower whirlpools -- could have sworn this was from Denny & Drew's IGORs or someplace like that, where they get actual lab results. Guess I'll have to listen to some more podcasts or look into this some more. Hmm.

Sorry if I'm wrong. I try to be right. If anyone wants to look this up for me, I'm all ears & eyes. Thanks.

dmtaylor said:

Seriously?

Sorry if I'm wrong. I try to be right. If anyone wants to look this up for me, I'm all ears & eyes. Thanks.

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You should look it up before you post.

ClaudiusB said:

You should look it up before you post.

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Nah, I'm very lazy. I memorize and express conclusions, but forget supporting details. It's a fault of mine, and for this I do apologize. But since we are now exchanging advice:

All info on the interwebs should be taken with grains of salt, as there are always exceptions to every absolute statement.

I shall add this as a permanent disclaimer to my .sig so that I won't need to apologize anymore.

Cheers.

mabrungard said:

Dave, that is not what the laboratory data from Shellhammer and Malewicki found. The activation energy needed to isomerize alpha acids is equivalent to a wort temperature of 185F. Therefore in the typical post-boil whirlpool, the wort will continue to become more bitter since the wort temp is still above 185F during that stand.

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Remember that temperature is a measure of the MS velocity (average kinnetic energy) of particles. thus at 185 °F some will have energy greater than that corresponding to exacty 185 and some less. At a temperature below 185 there will still be lots of molecules/particles with kinnetic energy greater than the activation energy.

dmtaylor said:

I've heard it said that the human palate detects IBUs in packets of 3-4 IBUs each. So, you can tell the difference between like 20 & 25 IBUs, or 65 & 70 IBUs, but not 20 & 22 IBUs or 65 & 67 IBUs.

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You may in fact be entirely correct but the human body tends to respond, above threshold, to the log of the stimulus. Thus for sound or light you can detect a change of about 25%. It is reasonable to suppose, therefore, that one would be able to detect a 25% change in bitterness but I don't have any data that says that this is, in fact, the case.

dmtaylor said:

Nah, I'm very lazy. I memorize and express conclusions, but forget supporting details. It's a fault of mine, and for this I do apologize. But since we are now exchanging advice:

All info on the interwebs should be taken with grains of salt, as there are always exceptions to every absolute statement.

I shall add this as a permanent disclaimer to my .sig so that I won't need to apologize anymore.

Cheers.

Click to expand...

I already have that in my sig.