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Whirlpool hops / IBU calculations

jclayton

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Later this week I will be attempting my first recipe utilizing whirlpool hops. I notice that as expected, BS 2.0 attributes no IBU's to flameout hop additions, however, my 10 min whirlpool additions are contributing several IBUS. I am not clear on exactly how whirlpool hops work in terms of IBU addition.

I plan to leave my flameout hops in the kettle during whirlpool, will that not also add additional IBUs since they will effectively be whirlpool hops at that point? The recipe is calling for 10 min whirlpool, am I correct that i need to keep the wort temp above 170 during those 10 mins?

This is a super hoppy wheat beer, but it is all flameout and whirlpool hops minus some hop extract at 60min. I usually don't obsess this much with IBU, but would like to try to better understand my software as well as protect the balance of this brew.

Thanks




 
jclayton said:
This is a super hoppy wheat beer.

IBUs hit plateaus on many levels. "It depends" has as 10x as many possibilities as you and I can think of together ...with beer.

Here's just a couple of basics and a reality check.

IBUs do not estimate aromatics.

Reality Check: If the recipe has over 50 IBU, then most of what you're adding is usually flavor, regardless of when hops are added.

The models for whirlpool additions are evolving. According to most models and a recent homebrewer experiment, they are pretty much the same as 20 minute additions, which is what the current model emulates. Scholarly research has only begun to emerge in the last two or three years. Nothing is definite.

If you're whirlpooling and settling for more then 10 minutes before chilling, then shift everything less than 5 minutes to a WP addition. The current BeerSmith (2.2) does segregate IBU contributions between boil and whirlpool but a future update may remedy that.

 
I know this is an old thread, but I'm just putting together a NEIPA recipe and noticing that the calculated IBUs are higher than I expect for the whirlpool additions. Rather than starting a new thread I figured I'd search for my issue and this thread seems to nail it.

I am curious what temperature BS thinks the hops are steeping at for this calculation. Is it assuming the wort is just below boiling for all "steep" additions, or does it take into account that below 180?F very little alpha acid is isomerized into perceived bitterness...? I am using a counterflow chiller in my whirlpool loop and expect the wort to cool to below 180? fairly rapidly after flame-out...so most of my whirlpool additions should be below 180?...
 
Generally, this first attempt at modeling the IBU contribution assumes a utilization % which can be set in your 'options' settings for expected isomerization of the hop acids.  This is based on papers which claim that the bitterness attained during whirlpool hopping is equivalent to about 1/2 the utilization for same amount of time if those hops were added during the boil.  The present version does NOT take into account the temperatures of the hop additions.  I am pretty sure that Brad has stated that will come with the next release/update but at present I cannot find that response from him.
 
I just found this article: https://byo.com/article/hop-stands/

I'll have to play around with Beersmith some more this evening...sounds like I might need to adjust my steeping times in the recipe to reflect the IBUs that I expect, and then compensate on brew day with the correct times...would be nice to have a setting in the ingredient options that configures either temperature or estimated utilization for a particular contribution...
 
Ok, it looks like the best way to handle this may be to modify the AA% of each hop addition in the whirlpool, weighted by when it is added...

I'm just making some estimates here based on the research I've seen...but I'm doing a 20 minute whirlpool and 20 minute trub settle, so for Flame-out hops (40 minutes before racking), Beersmith is already adding a 50% hop utilization correction, which is probably about right, so I'm leaving the AA alone for those hops.

For my next hop addition with 30 minutes left, the wort should be well under 180F, so I've reduced the AA for those hops by 50%. For my last addition when I shut off the pump at 20 mins, the wort will be at pitching temp, and I reduced the AA by another 50% (or 25% of the original AA value).

I guess short of having the beer tested for iso-alpha acids after brewing there really isn't any way to know for sure if those are reasonable assumptions...

Thoughts?
 
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