Author Topic: Estimate Boil Hop Util in Whirlpool  (Read 3790 times)

Offline 1HW

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Estimate Boil Hop Util in Whirlpool
« on: September 02, 2020, 02:47:35 PM »
Hi all,

I have a question about how to use "Estimate Boil Hop Util in Whirlpool" switch in the Equipment Profile. It is recommended to use it if steeping/whirlpooling. 



If I understand the point of this switch, it makes an assumption that the hops added during the boil continue to contribute IBUs during the steep/whirlpool.

Here are examples of hop additions at 30 mins, 15 mins, 1 min, and 0 min, as well as a 15 minute steep at 180 degrees:

Switch On.



Switch Off.



Note that there is a small, extra IBU contribution from the 30 min addition with the switch on (+3 IBU).  The effects are more pronounced at 15 mins (+6), and are considerably different at 1 and 0 mins (+13-14 IBUs).  This would make sense of course if the 30 min addition was mostly "finished" in terms of contributing IBUs by the time the hop stand begins whereas the later additions effectively have more to give.

My question is how to interpret the 1 min and 0 min additions. Specifically, when the switch is "off", their IBU contributions are effectively nil; when the switch "on", the IBU contributions are significant. Indeed, for a NEIPA-style beer where most/all of the hop additions come late or ass zero minute additions, the distinction can effectively double the IBUs for the recipe.

One interpretation would be that there is disagreement in the field as to whether late addition hops actually contribute IBUs.  If you believe they do, turn the switch on.  If you're a non-believer, leave the switch off.  Perhaps one day we'll know who's right.

An alternative interpretation is that it is well-established that boil additions will continue to add IBUs throughout a hopstand, and the purpose of the switch is to distinguish that situation from one where boil hops are removed at the end of the boil and therefore can not contribute additional IBUs.  Another way of thinking about this scenario would be adding an ounce of hops at the 0 min mark and then immediately removing them a second later.  In this example, the IBUs would literally be 0, and this is consistent with what BeerSmith shows for a 0 min addition with the switch off.

Thanks in advance for any insight/feedback you might offer.

-Bill


Offline Oginme

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Re: Estimate Boil Hop Util in Whirlpool
« Reply #1 on: September 02, 2020, 05:21:43 PM »
When you try to interpret the 1 minute or 0 minute hop additions, it helps to know how hop utilization works.  First, the rate at which hop acids isomerize is not linear with time.  I have attached the chart of isomerization from which the Tinseth model for predicting IBU was derived.  Next, while we like to think that once the heat is off, isomerization stops, but the isomerization (and also oxidation) of alpha and beta acids continues down to around 170F (77C), albeit at a much slower rate.  This is why a brewer can make a beer with all steep/whirlpool hop additions and still end up with a reasonably bitter beer.  I made a pretty nice pale ale that way a couple of years back.

Even if you were to dunk the hops in a zero minutes and remove then a minute later, the liberated alpha acids will still continue to isomerize until the temperature of the wort is dropped low enough to stop the reaction.

« Last Edit: September 02, 2020, 05:50:12 PM by Oginme »
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Offline 1HW

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Re: Estimate Boil Hop Util in Whirlpool
« Reply #2 on: September 03, 2020, 06:01:43 AM »
Many thanks for that explanation.  And so if hop isomerization continues (nonlinearly) through 170 F, then it begs the question of why a 0 minute hop addition would show 0 IBUs with the "Estimate Boil Hop Util in Whirlpool" switch turned off?  The wort is obviously oblivious to software settings and is presumably doing what the graph shows...

I guess what I am trying to understand is under what circumstance should the switch ever be "off".  I can think of two, and perhaps this is the purpose of the switch:

1.  If you added a 0 min addition and immediately removed it.  This would be pointless, of course, and no one would waste hops in that manner.  That said, if someone did this, then the 0 min addition would not isomerize as the wort chilled to 170.

2.  If you added a late hop addition, and at the end of the boil, you very rapidly chilled the wort below 170.  In this case, the isomerization of hop oils would continue briefly during the rapid cooling period but would not contribute significant IBUs in the way they otherwise would if you held temp above 170 for a hopstand or whirlpool. 

Am I understanding the functionality correctly? This seems like a tricky thing to estimate accurately because the software does not know how long the wort remains above 170 F at boil end.  The software could, in theory, estimate by using hop stand temps and lengths inputed into recipes to better estimate IBUs, but it doesn't seem to be doing this.  If I change the length of the hopstand, or if I lower the temp of the hopstand to 160 or some such, the IBUs do not adjust accordingly.

In short, the software doesn't seem to care how quickly the wort is chilled to a point where isomerization stops, and this seems to really matter according to your reply.  If the switch is off, it assumes hop contributions to IBUs magically end at the end of the boil.  If the switch is on, it assumes there is a fixed contribution of late addition hops to IBUs regardless of how long the wort holds above 170. 




Offline 1HW

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Re: Estimate Boil Hop Util in Whirlpool
« Reply #3 on: September 03, 2020, 06:09:07 AM »
Quote
In short, the software doesn't seem to care how quickly the wort is chilled to a point where isomerization stops, and this seems to really matter according to your reply.  If the switch is off, it assumes hop contributions to IBUs magically end at the end of the boil.  If the switch is on, it assumes there is a fixed contribution of late addition hops to IBUs regardless of how long the wort holds above 170.

I (hop)stand corrected.  The software does try to estimate chill time by using the setting specified in the equipment profile above the checkbox as answered by Oginme in this post:

http://www.beersmith.com/forum/index.php/topic,21521.0.html




So to be most accurate, we need to estimate time above 170/160 and set that value in the equipment profile as the software does not use any recipe-entered hopstand/temp to compute the estimates.

« Last Edit: September 03, 2020, 06:21:09 AM by 1HW »

Offline Oginme

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Re: Estimate Boil Hop Util in Whirlpool
« Reply #4 on: September 03, 2020, 06:43:05 AM »
The premise of the 0 minute addition of hops is that the user is chilling down the wort quickly after the boil is over to preserve the aromatics over any gain of bitterness.  For all practical purposes, the gain of IBU with a flame out addition of hops is so low if the wort is cooled quickly that the bitterness realized disappears in the variability of the calculation versus the actual process realization.  If you have any amount of delay, then it is really a steeping addition added at near boiling temperature which should actually be added as a whirlpool/steep addition. 

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Offline FunkedOut

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Re: Estimate Boil Hop Util in Whirlpool
« Reply #5 on: April 09, 2021, 09:26:23 AM »
Another look at this same setting to help flush out the understanding.

I have been brewing with an immersion chiller and managed to get the wort to below 170*F within a couple of minutes, so I have never checked the box to estimate hop utilization in whirlpool.
I have recently upsized my batches from 5 gallons to 15 gallons. 
Along with this upsize, came a counterflow chiller.
I am now chilling on the way to the fermenter.
I bag my hops in the kettle, and they remain in contact with the wort for about 10 minutes, as it is pumped out.
It takes a total of 20 minutes to pump the wort out completely.

My first thought is to check the box on and set the whirlpool time to 10 minutes:


With no actual whirlpool hops added, what temperature is used by the software to calculate isomerization rate for the boil hops carry over?
Is there a target temp to use for setting the "whirlpool time" in the equipment profile?

In the same recipe, with the Hop Utilization and Whirlpool Options set as above, it seems a 10 minute whirlpool at 207*F results in the same IBU's as a 0 min boil addition:


Thanks in advance for your thoughts.


Offline Oginme

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Re: Estimate Boil Hop Util in Whirlpool
« Reply #6 on: April 09, 2021, 11:25:13 AM »
0 minute hop additions in BeerSmith have always assumed that the wort is chilled down immediately following flame out so there is no IBU generation of note using this method.  I switched my 0 minute additions to be a whirlpool addition at boiling temperature (99C/210F at my elevation) and set the whirlpool time to 10 minutes (assuming no other whirlpool hop additions.)  This time period accounts for my typical end of boil process of turning heat off, removing hop basket/bags, measuring and recording volume, measuring Brix, taking a hydrometer sample (when I bother to measure by hydrometer), and putting my chiller in, which takes me 10 minutes until I turn the cold water on to start chilling. 

Being too lazy to actually measure IBU (I have access to the equipment, just never bothered to get the solvent for the procedure), I have done sensory testing of late boil hops (5 minutes) vs same hops added at 82C/180F for 20 minutes with no boil hops added and from my senses (questionable to be sure) I get an equivalent bitterness.  Saying that, this is what I get in my process, at my elevation, and with my equipment.  Your mileage may vary.

When it comes to actual IBU numbers, I really don't pay that much attention to them as much as what my sensory evaluation tells me.  Good notes go a long way.  Once I lock down the recipe development in terms of additions and times, then the IBU for each addition becomes my target -- for that addition and in that recipe!
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Offline FunkedOut

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Re: Estimate Boil Hop Util in Whirlpool
« Reply #7 on: April 09, 2021, 11:36:05 AM »
0 minute hop additions in BeerSmith have always assumed that the wort is chilled down immediately following flame out so there is no IBU generation of note using this method....

This is not true with the settings I have outlined above.
Not sure why my pics are so small, but click on them to see what I am talking about.
My 0min boil addition is calculated to contribute 3.5 IBU; the same 3.5 IBU as the the 10 minute whirlpool addition at 207*F.
Equipment settings have a 10 minutes whirlpool and the box checked.

Offline Oginme

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Re: Estimate Boil Hop Util in Whirlpool
« Reply #8 on: April 09, 2021, 11:57:02 AM »
Sorry, I guess I was not clear.  The original expectation of the 0 minute hop addition in BeerSmith was without the whirlpool time in the equipment profile.  The estimation of IBU from whirlpool and post boil steep is purely a guess and, from all the research I have found to date, not backed up by the IBU models which are presently being used.  The most accurate I have seen is from a commercial system where their tests estimated the utilization of boil hops was approximately the same value a boil hop addition made at half the steep/whirlpool time (i.e. 10 minutes of hop steep was equivalent to approximately 5 minute boil hop addition with regard to measured IBU).  Since this is purely a guess, I use my sensory testing done with over a dozen brews varying a single hop boil addition times as compared to a single whirlpool hop addition at several temperatures and steep times.  As I said before, too lazy to actually buy the solvent to test it out exactly.  Since the value of calculated IBU is reasonably close to actual (+/- 5 to 10 IBU for most brews) but definitely unique to the process parameters as boil off rate, boil vigor, etc., I use them for benchmarking while the recipe is being developed over a series of brews and when I have finished messing around with the recipe.
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Offline FunkedOut

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Re: Estimate Boil Hop Util in Whirlpool
« Reply #9 on: April 10, 2021, 10:18:31 AM »
Appreciate the discussion and data points.

I totally agree with you on the point about sensory analysis being more valuable than IBU measurements.
However, I like to draw a correlation between calculated IBU's and sensory analysis to enable future tweaks or recipes to be close enough based on the calculations.

Looks like I might be able to set my whirlpool time in the equipment profile to 5 minutes, based on my process and get in the ballpark.
I have my first brew in the fermentor now, and can start to build that calculation/correlation back up with this new process.

I think I'll keep my 2 minute additions as boil additions and see if the whirlpool settings in the equipment profile line up with what my beer tastes like.

Thanks again.