I need a little clarification. The terms flameout, whirlpool and hopstand, get thrown around a lot. I always assumed they were interchangeable terms but I’ll bet I’m wrong. What’s the consensus?
Flameout- add hops to wort as you turn off your heat source and immediately begin chilling
Hop stand- chill to a specific temperature, add hops to wort, and hold at or near that temperature for a specific time
Whirlpool- I’ve never done that one. I’ll let someone else answer.
I’d say that whirlpool is either of the first two, but adding a (re)circulation to the kettle, whether by pump or stirring, then letting the debris settle to the middle of the kettle before racking to primary.
Whirlpool refers to a craft brewers practice of adding hops to a whirlpool to drop out hot break before the wort is cooled in a heat exchanger. Whirlpooling is a continuous process - hot wort is introduced into the whirlpool while whirlpooled wort is drawn off. In homebrew speak, whirlpooling can be the same as hop stand AFAIK.
I find this post quite informative. I will be attempting a NEIPA in January and the recipe I’m looking at calls for hop additions at two of these points - whirlpool and hopstand. However, when I enter this schedule into BS3, the IBU increase is very minimal.
So, I guess my question is: at what temperature do hops no longer give up bitterness? Other than adding dry hops into the secondary, I’ve never added hops past the flameout stage. So any additional information and knowledge on this subject would be appreciated. Thanks!!! 
This article has lots of info about hop utilization at varying temperatures: An Analysis of Sub-Boiling Hop Utilization | alchemyoverlord
This article sure does have a lot of info!! Ill check it out! Thanks for sharing it!
One of the reasons that I use the Grainfather recipe software is because it implements the mIBU formula from that site. It takes into account whirlpool and even dry hop additions.
First off, “flameout” is not a real brewing term (I challenge anyone to find a reference to that term pre-craft beer movement). It was coined by some home brewer post-2000 because it was not in general use for the first decade that I brewed. The traditional term is “knockout” or in old school home brewing terms “time 0” hops. It is like the use home brewer term “dough-in” instead of the professional brewer and distiller term “mash-in.” It is the opposite of “mash-out.” A dough-in is a specific type of mash-in that uses a very low hot liquor to grist ratio. Greg Noonan covered it in his book on lager brewing. There is a lot of stupid in home brewing that one cannot fix and in my humble opinion “flameout” and “dough-in” are prime examples, so is the use of Erlenmeyer flasks and stir plates for yeast propagation, but I digress.
With that said, as other have mentioned hop stands and whirlpool hopping are specialize forms of knock-out additions.
Simply because a term is coined by a homebrewer doesn’t mean it’s not “real” brewing terminology.
I have to disagree with you, Denny. We should not be fragmenting the brewing lexicon. There is a difference between creating a new term for a new process and renaming an existing process because one’s level of literacy in a discipline is lacking. Discipline lexicons exist for a reason. They exist to give practitioners a common language with which to exchange information. Both “dough-in” and “flameout” are prime examples of brewing lexicon fragmentation. These terms were created out of brewing illiteracy and all they do is add confusion to an already often confusing discipline. Case in point, the non-brewing term “flameout” has become so ubiquitous that even John Palmer has been forced to use it. However, if one read’s his book, one quickly discovers that he used the term “knockout.” The term “knockout” has been used in brewing for hundreds of years. Flameout is little more than an red-headed stepchild born from brewing illiteracy. It is an example of Mr. Ron White means when he says, “you cannot fix stupid.”
You are free to disagree. I see it as augmenting, not fragmenting. I’m a homebrewer…things are often different for me than for a commercial brewer.
With electric brewing becoming so much more common, the term “flameout” is already becoming an anachronism even within the homebrewing community. Perhaps we electric brewers should say “sparkout”. Or maybe “knockout” covers it, although it is not clear to me what was being knocked up to that point.
Yep. Kinda like when people say they’re “taping” something when they record it.
Frankly, I always thought the term “knockout” was slang….
After reading this article, I have come to the conclusion that IBU contribution below boil temperature, while present, is minimal and highly dependent on hop freshness and packaging. I have also concluded that the subject has given me a headache! ;) That said, it was a very informative article with links to supportive documentation that will also be very useful. Thanks again for sharing!
You’re welcome - I’m glad you found it useful. I use the chart in Figure 2 to estimate the IBU contributed by the hop stand hops, and when using fairly high alpha hops, it’s substantial. Naturally, it’s highly dependent on temperature and other factors. I’ve found that the chart matches my perception of the bitterness.