Picking up "Extra" bitterness from late additions and then long whirlpool/knockout

[Ajchocholousek]

Hi All,

TL;DR version: Calculating in Beersmith, do I need to worry about large amounts of late addition hops continuing to isomerize and produce bitterness during our whirlpool/knockout which happens over about 90 minutes at 200F+? 1.056 OG, 17 bbl knockout. I don't want the perceived bitterness to get out of hand.

I've done a LOT of searching around on here, and I have mostly found old posts with shaky at best information. So, here's my attempt to find out more...

I'm a new brewer at a decent-sized (1100-1200bbl/yr) brewpub, and I have been tasked with completely re-designing our old APA recipe, which was forgettable at best. I'm super excited at this prospect, and I really want to nail it. I want to focus on cascade aroma and flavor with restrained bitterness, so I'm considering a "hop-bursting" technique. We haven't done this on our system here before (late additions, sure, but not a larger series of additions at the end), so I'm trying to nail it down on paper as much as possible before we brew (no pilot system. I will be trying it as homebrew, but it's hard to replicate the conditions that are creating the questions I have here.)

I'm mostly concerned about the late additions getting out of hand with bitterness as they sit for 90+ minutes above 200F while whirlpooling, settling, knocking out, etc. Is there any good way to calculate about how much more IBU I'll pick up from the <20 minute additions? Would those IBUs ever come across as straight bitterness? I know this sounds rudimentary (obviously I know that late additions favor aroma and flavor, that's why I'm doing them), but I'm slightly worried about overwhelming this ~6% pale.

Preliminary Recipe:

Malt:
57.3% US 2-Row Pale
26% US Pilsener
5.2% Munich 10
5.2% Munich 20
3.6% C-40
2.6% Carapils

Mash 60 min. at 153F, mash out to 170F

Hops (IBU from Beersmith)
60 minutes: ~20 IBU (Warrior)
20 minutes: ~8 IBU (Cascade)
10 minutes: ~4.7 IBU (C)
5 minutes: ~2.6 IBU (C)
Flame Out: ~7 IBU (C)
Big Dry Hop - details TBD

Conan Yeast - 67F

Thanks in advance for any guidance.

[NS_Nano]

Depending on how you chill, you could get around the issue (and maybe improve your beer) by adopting the approach of adding your whirlpool addition after your temp has dropped substantially, as suggested by James Altweis of Gorst Valley Hops. He suggests adding whirlpool additions at 120 F, to preserve the most volatile hop compounds. The whole discussion is really good, but I have linked to the beginning of the relevant part of the discussion here: <https://youtu.be/7qD17ZeTSsE?t=2055>.

[lhall]

Why exactly does the knockout take so long? 90 min is too long. You are risking a lot of DMS production.

[mmussen]

As long as your beer is over about 170 you will get some isomerization of alpha acids. That being said 90 min after the boil is a very long time. Even with a 10 min whirlpool and a rest I've got the entire batch of beer through the hx in about 50 min.

[briangaylor]

Does anyone go from the kettle to the heat exchanger to the whirlpool to get the temp down lower (140-170) before tossing in their whirlpool hops? The thought being you keep more of the flavors/aromas that may get 'flashed' out at higher temps without having to let it sit for 90+ minutes.

[TonyT]

TL;DR reply, yes you'll pick up bitterness in the whirlpool.

It's not always easy to calculate how much. I have relied on trials and taste comparison to dial in amounts of whirlpool bitterness. Also, not to be nitpicky, but hops at 60, 20, 10, 5, and whirlpool isn't really hop bursting. Hop bursting, as I understand it, is 100% (or close to it) in the whirlpool, picking up all your bitterness, flavor and aroma there. Our american pale ale is whirlpool and dry hop only, and its quite bitter with big hop character.

[Swags]

Whirlpool addition IBUs in Beersmith

In my version of Beersmith, you can set the input for whirlpool additions as "steeping hops". I use 25 min. As my Beersmith input to approximate the IBUs gained from 15 min. Whirlpool, 10 min, rest and a 60 min. Knockout, Which is longer than i'd like b/c my HX is undersized. Using 25 min. As the steeping time seems to give me about the right bitterness level when combined with the IBUs from the 90 min. Addition.

[Ajchocholousek]

Why exactly does the knockout take so long? 90 min is too long. You are risking a lot of DMS production.

Well, I am figuring basically somewhere 90 minutes post-boil to fermenter total. So...

15-20 minute whirlpool, depending on hop quantity
15-20 minute rest
+55-65 minute knockout for hop-heavy beers
----------------------------------
85-105 minutes total post-boil, and the kettle rarely drops below 200F after all this. Hops are in there the whole time, albeit in a cone for part of it.

So far no noticeable DMS, except in one batch of pilsner that took 90 minutes for knockout alone (damn 1.5% AA Hersbrucker)

[Ajchocholousek]

Does anyone go from the kettle to the heat exchanger to the whirlpool to get the temp down lower (140-170) before tossing in their whirlpool hops? The thought being you keep more of the flavors/aromas that may get 'flashed' out at higher temps without having to let it sit for 90+ minutes.

This has definitely crossed my mind, and it's actually the approach I'd like to take, but our head brewer is less excited about it.

I'm thinking: short whirlpool, short rest, run through heatX back to kettle to get temp down to 170, hop stand, whirlpool, rest, KO...?

[Ajchocholousek]

Sorry, just figured out how to multi-quote!

In my version of Beersmith, you can set the input for whirlpool additions as "steeping hops". I use 25 min. As my Beersmith input to approximate the IBUs gained from 15 min. Whirlpool, 10 min, rest and a 60 min. Knockout, Which is longer than i'd like b/c my HX is undersized. Using 25 min. As the steeping time seems to give me about the right bitterness level when combined with the IBUs from the 90 min. Addition.

This is sort of what I'm doing now, as well. Have you had any IBU lab analysis done to see how close it is? I still feel like I'm shooting in the dark a bit...

TL;DR reply, yes you'll pick up bitterness in the whirlpool.

It's not always easy to calculate how much. I have relied on trials and taste comparison to dial in amounts of whirlpool bitterness. Also, not to be nitpicky, but hops at 60, 20, 10, 5, and whirlpool isn't really hop bursting. Hop bursting, as I understand it, is 100% (or close to it) in the whirlpool, picking up all your bitterness, flavor and aroma there. Our american pale ale is whirlpool and dry hop only, and its quite bitter with big hop character.

I guess I just used the term since I've found it to be fairly broadly and vaguely defined. As I understand it, it just refers to a series of small additions after say ~20 minutes in lieu, for example, of traditional ~30 minute "flavor" additions or whatever. All in an effort to keep perceived bitterness low, while maximizing aroma and flavor. Semantics, I suppose.

[barleyfreak]

In my version of Beersmith, you can set the input for whirlpool additions as "steeping hops". I use 25 min. As my Beersmith input to approximate the IBUs gained from 15 min. Whirlpool, 10 min, rest and a 60 min. Knockout, Which is longer than i'd like b/c my HX is undersized. Using 25 min. As the steeping time seems to give me about the right bitterness level when combined with the IBUs from the 90 min. Addition.

This is very close to what I am doing. 5 minute whirlpool, 20 minute rest = 25 minutes "steep/whirlpool" in beersmith. It amounts to about 60% of the calculated bitterness from the WP and the rest from my 90 minute addition. I have yet to send any to a lab -- but the taste test seems consistent at this point. I do note that my knockouts in the summer w/ 74 degree incoming water through a pre-chiller run about 60-70 minutes. IN the winter, about half that much. I thought I'd extract more bitterness in the summer due to the longer knock out times, but I honestly can't tell much difference.

[Ajchocholousek]

This is very close to what I am doing. 5 minute whirlpool, 20 minute rest = 25 minutes "steep/whirlpool" in beersmith. It amounts to about 60% of the calculated bitterness from the WP and the rest from my 90 minute addition. I have yet to send any to a lab -- but the taste test seems consistent at this point. I do note that my knockouts in the summer w/ 74 degree incoming water through a pre-chiller run about 60-70 minutes. IN the winter, about half that much. I thought I'd extract more bitterness in the summer due to the longer knock out times, but I honestly can't tell much difference.

Cool. Thanks for the info. Just to confirm, let's say we're shooting for 40 IBUs in an APA. You're saying that your late additions in Beersmith, when set to "steep" for 25 min. come to about 24 IBUs (60%), your early addition makes up the remaining 26 (40%), and you're about right on for perceived bitterness? Is this with just one early addition and one big late addition?

[barleyfreak]

Cool. Thanks for the info. Just to confirm, let's say we're shooting for 40 IBUs in an APA. You're saying that your late additions in Beersmith, when set to "steep" for 25 min. come to about 24 IBUs (60%), your early addition makes up the remaining 26 (40%), and you're about right on for perceived bitterness? Is this with just one early addition and one big late addition?

Pretty much. In our IPA we get 23 IBU's (calculated via Beersmith) from a 1lb 90 minute first wort addition, and another 42 IBUs from the 12lbs whirlpool/rested for 25 minutes. For a 7 bbl batch.

[Ajchocholousek]

Cool. Thanks for the info, folks. I'm feeling more confident on this one.

Shooting for about 41 IBUs on a 1.056 APA:

~20 IBU coming from First Wort, 75 minute addition
~11 IBU coming from 15 and 10 minute additions
~10 IBU coming from WP addition (30 minute steep calculated from Beersmith)

Does this sound reasonable?

Cheers,

Alex

[Ajchocholousek]

Pretty much. In our IPA we get 23 IBU's (calculated via Beersmith) from a 1lb 90 minute first wort addition, and another 42 IBUs from the 12lbs whirlpool/rested for 25 minutes. For a 7 bbl batch.

Also, I'm assuming you mean to say your last addition gets you up to 42 IBU total? I doesn't add a full 42, correct?