Why does the recipe builder give reduced IBU for FWH'ing

[OkanaganMike]

Doing some research about FWH'ing to understand why the recipe builder shows a reduced IBU when FWH is selected over 60 minute boil.

Unless I'm misunderstanding this article ( https://www.homebrewersassociation.org/how-to-brew/what-is-first-wort-hopping/ ), I think there is a problem with the calculator as the IBU should be increased not decreased.

Thoughts?

 

[Ozarks Mountain Brewery]

I think this has already been discussed in another thread, I would suggest you try it first to see if you can tell the difference, I have many times and my beers are not more bitter tasting as a matter of fact their less

 

[OkanaganMike]

Just trying to get my head around the science of it. Didn't make sense to me since the hops remained in the boil and want to know how the oils are affected with time allowed for isomerization.

 

[Ozarks Mountain Brewery]

without getting into specifics if your forward hopping they are not boiling yet

 

[Yooper]

We are in the process of fixing it. It should give you higher IBUs than the bittering addition, but some say it's a smoother bitterness. I go with the IBUs of the 60 minute addition + 10% in my own brewing, and that is what we are changing it to be.

 

[GFHomebrew]

I've done two consecutive FWH brews there mike actually one of them was in a 90 minute boil and I thought the bitterness is going to be overwhelming but it turned out quite smooth so I can attest to the smooth bitterness theory.

My last brew I started Bittering at 60 min no FWH it's a little sharper but as for aroma or flavour from FWH I'm yet to be convinced if anything it's just a smoother bitterness. I think it's something about the hop oils being isomerised at lower mash out temperatures before the wort is heated to boiling similar to 80c whirlpool hops as they are added around same temperature. I mash out at 74 ish centigrade for ten minutes then sparge at 74c for probably 10minutes so they are sitting in this warm wort temperature for at least 30minutes before the boil begins.

As for me I biab so I've been thinking maybe some of the hops may have got stuck to the outside of my brew bag.

 

[OkanaganMike]

I'd sure like to try a side by side test of FWH and 60min addtn to see for myself. Prolly will never get around to it though. Thanks Yooper, seems to me it should give a higher IBU too but at the end of the day, I'm not taking it to a lab to check. Just like to pretend I understand how the processes work.