Author Topic: Hop Utilization in Whirlpool  (Read 15775 times)

Offline largeselection

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Hop Utilization in Whirlpool
« on: March 31, 2014, 09:43:05 AM »
I love that the recent update to BeerSmith includes the option to add whirlpool hops and calculates IBUs which result from those additions.  The question I have is whether I need to add late boil additions to the whirlpool also for calculating correct IBUs.  Lately some of my beers have been coming out overhopped compared to the recipe (and yes I adjusted the utilization factor up). 

The reason why I have this question is because I noticed that if I add
0.5 kg of 7%AA hops at 1 minute in the boil it says it contributes 0.1 IBUs

If I add
0.5 kg of 7%AA hops for the last 15 minutes of the whirlpool it says it contributes 0.5 IBUs. 

Now the reason that strikes me as somewhat odd is that the 0.5 kg of hops that I add in the last minute of the boil all gets transferred into the whirlpool anyway, but it seems that the assumption is that once it transfers to the whirlpool then it stops contributing? 

So I guess my question is - would it be more accurate to input this in the recipe (assuming whirlpooling takes 30 minutes)

0.5 kg of 7% AA hops at 1 minute in the boil
0.5 kg of 7% AA hops for 40 minutes in the whirlpool (These is the same addition as the 1 minute boil addition, but now transferred into the whirlpool)
0.5 kg of 7% AA hops for 15 minutes in the whirlpool (we add more hops directly into the whirlpool)

Logically it would seem that makes more sense because that should reflect the fact that there are still IBUs being contributed by the late boil hop additions?

What do you all think?  Is there something I'm not understanding correctly?

Thanks in advance for the help!

Offline RiverBrewer

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Re: Hop Utilization in Whirlpool
« Reply #1 on: March 31, 2014, 04:39:28 PM »
If your whirlpooling, what is the point of a 1 or 10 minute addition.?????? Your 1 minute addition will continue to add bitterness until your wort hits 170 degrees F. Increasing the bitterness. So if you whirlpool for 45 minutes more to get to 170 F. You have 46 minutes of isomerization. Just compensate with your bittering, first wort hopping additions, or whirlpool additions.

I am sure the software when it sees a late addition is calculating the IBU's to flameout followed by quick cooling by a chiller.
There isn't much research available of whirpooling. How you do it, try to be consistent, I focus more on the temp. It takes about 45 minutes for my wort to drop to 170 degrees F. So I pump my whirlpool for 45 minutes, if I want to add a second addition, I add it then, < 170 degress F.
Pump another 10 minutes, and let settle for 20 minutes, then its chiller time.

I like first wort hopping with whirlpooling, just my preference, smoother bittering.
Woops! Sorry I didn't notice this was a "Pro" post. My boil pot is only 30 gallons.
I hope there is something useful in this post for you.
« Last Edit: April 01, 2014, 01:49:58 PM by RiverBrewer »
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Offline brewfun

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Re: Hop Utilization in Whirlpool
« Reply #2 on: April 01, 2014, 05:53:47 PM »
If I add 0.5 kg of 7%AA hops for the last 15 minutes of the whirlpool it says it contributes 0.5 IBUs. 

Now the reason that strikes me as somewhat odd is that the 0.5 kg of hops that I add in the last minute of the boil all gets transferred into the whirlpool anyway, but it seems that the assumption is that once it transfers to the whirlpool then it stops contributing? 

BeerSmith is not currently set up to do timed whirlpool additions. It assumes whirlpool hops are in at the beginning.

In my case, the recipe whirlpool time tells the shift brewer how long the whirlpool is expected to run. Our whirlpools are minimum 20 minutes and go to 45 for more aromatic beers.

 As a matter of brewhouse practice, whirlpool hops are all added at the last minute of the boil so they hydrate and immerse instead of matting on top. But they show on the recipe as whirlpool additions.

To the best of my knowledge, whirlpool utilization is anecdotal at best. Papers coming from the ASBC are showing whirlpool utilization is driven mostly by CoHumulone content because that isomerizes faster than Humulone and Adhumulone. It also takes less vigor to fix CoH as an isomer. The papers showing continued isomerization are only going to 50 IBU and in just 12-14 P wort.

I don't think there is consensus on whirlpool utilization that would help with hop saturated worts. The flavors you're describing affect my 12 P wheat and 14 P Pilsner, but are seemingly absent in my Pale Ale, IPA and DIPA that are well over 70 IBU in the boil.

Recently, we retrofitted the brewhouse pump for a number of improvements. Among them is that the whirlpool velocity has been reduced. It used to recirculate close to 100% of the wort in 20 minutes, creating a lot of shearing. Now it's about 30%, and less shearing occurs, the hotbreak stays bigger and we've noticed a reduced coarseness to some beers. This may mean fewer isomers are created or less CoH is being isomerized or more AA is captured by trub. I really can't say. We haven't lab measured a sample, yet.
« Last Edit: April 01, 2014, 05:56:20 PM by brewfun »
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Offline RiverBrewer

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Re: Hop Utilization in Whirlpool
« Reply #3 on: April 01, 2014, 07:24:22 PM »
Brewfun: I have heard the term shearing before when it comes to pumping wort. Am I correct that liquid part of the wort moves faster than the hot break and trub and that causes the trub and protein to be broken or ground into smaller particles. What are the effects of shearing on the finished product? Haze? Flocculation?
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Offline brewfun

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Re: Hop Utilization in Whirlpool
« Reply #4 on: April 02, 2014, 01:52:06 AM »
Shearing is a pro term that gets thrown around a lot and encompasses issues in the mash, pump overs and whirlpool. Your assumption is correct that it all means mechanically tearing larger particles into smaller ones.

Sometimes you want a little of it, but more often, you want to avoid it. Kinda depends on equipment design.

Without getting too detailed, in whirlpool hopping you want enough motion to scrub off and dissolve aromatic oils, but not so much that it tears up the plant matter. Heavier pieces settle better and don't get sucked into the heat exchanger as easily. Plus little bits of hot break end up in the fermenter and reducing that would be good.

The pump can momentarily super heat the wort in the impeller chamber. Since isomerization requires both heat and movement to speed the process, the impeller chamber seems to be a perfect environment. Add the movement of a faster than needed whirlpool speed and this *may* enhance or speed some isomerization in the whirlpool.

At full throttle, my pump moves about 35 to 40 gpm, which is enough to fully recirculate 100% of 19 bbl of wort in just 15 minutes. I recirculate IPA and DIPA for 45 minutes to enhance aroma. So, shearing can become a factor that I have to deal with in other ways.

The retrofit added a valve that cuts the flow by 75% (breweries are hard steel piped in custom increments. Retrofitting is no easy process). So now, about 200 gallons pass through the pump on 20 minutes which seems to cut way back on the shearing. It also seems to cut back on isomerization, or at least the perception of it.
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Offline brewfun

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Re: Hop Utilization in Whirlpool
« Reply #5 on: April 02, 2014, 02:03:18 AM »
It also takes less vigor to fix CoH as an isomer. The papers showing continued isomerization are only going to 50 IBU and in just 12-14 P wort.

I phrased this poorly.

The paper I'm describing only tested to 50 IBU. There is no data about how much more isomerization is possible. They stated that CoH was the most abundant isomer, but not the only one.

The wort represented mass lager !00% pale grist.

My take is that this is an important consideration in lighter and less bitter beer styles. I am not the slightest convinced that it's a consideration for hop saturated wort. I believe whirlpool hopping tilts far more towards aroma and flavor in those scenarios. Whirlpool Isomers created only replace the same quantity that is destroyed past 90 minute boil cycles.

Then there's the yeast to consider.... A whole other topic.
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Offline brewfun

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Re: Hop Utilization in Whirlpool
« Reply #6 on: April 12, 2014, 05:14:57 PM »
Topic Update:

In a hops seminar by Tom Shellhammer of Oregon State Univ, I had the chance to ask him about whirlpool contributions to finished IBU levels. Other than the study I cited before, he doesn't know of any published research on whirlpool IBU levels in worts that start at >50 IBU going in. He did think it'd be a good research topic. So, maybe next year....

He presented some very compelling data about what constitute Bittering Units. The amount of polyphenol contributed by large amounts of flavor and aroma hops is measured in an IBU reading.

It's substantial. As much as 30% of the measured IBUs in a highly hopped beer can be polyphenol driven. Since polyphenols have a long, slow reaction with malt proteins and oxygen, they reduce in both measured and perceived bitterness as haziness increases. Long, cold storage makes the haze drop out of suspension, so a drinker may still have a reasonably clear beer, but far less hop character.

Moreover, there is a very low point at which perceived bitterness diverges from measured BUs. This measurement requires tasters to use nose clips to eliminate cues from aroma. We've long known that significant aromatics drive consumer perceptions about "hoppiness" far more than mere bitterness.

This slide makes a compelling case that mere hop isomers are a minor factor in perceptions of "hoppy" in the taste of beer. The green dots represent the taster's rating for 0 (no hoppiness) to 15 (aggressively hoppy), while the yellow dots represent purely isomerized alpha acid (IAA) IBUs. No group said 15 on this scale.



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Offline grathan

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Re: Hop Utilization in Whirlpool
« Reply #7 on: April 12, 2014, 09:03:12 PM »
Quote
It's substantial. As much as 30% of the measured IBUs in a highly hopped beer can be polyphenol driven. Since polyphenols have a long, slow reaction with malt proteins and oxygen, they reduce in both measured and perceived bitterness as haziness increases. Long, cold storage makes the haze drop out of suspension, so a drinker may still have a reasonably clear beer, but far less hop character.

by hop character you mean the perceived bitterness from the polyphenols?