Hops added to mash does not affect IBU

[Kjetil Volden]

When adding hops and selecting "Mash" in the "Use" column, the utilization is 0%. It adds 0 IBU to the total, regardless of the amount and alpha %, which is obviously not correct. BeerSmith on the other hand, uses 20% of the utilization you would have by boiling the hops the equivalent time.

http://www.beersmith.com/Help/estimating_bitterness_tech.htm

(Using Brewtarget 2.1.0 on Windows 7.)

[Mik Firestone (mikfire)]

I have actually done a lot of reading on this. According to the papers I can find online, mash hopping offers no significant change to IBU. Mash temps are not hot enough to start isomerization and it appears that most of the oils stay with the spent grains. A few of the terpenes that do make it through have an effect on the perceived character of the hops, but there is no significant impact to the measured IBU.

I am happy to change my mind if you can dig up the research that says otherwise, but until then I am unwilling to change this.

[Kjetil Volden (kvolden)]

OK, I just trusted BeerSmith on this (ref. link in bug description). Also, I just found out -- to my embarrassment -- that one can adjust this utilization in Options -> Formulas.