I have tried searching for the answer to my question, but haven't come up with anything concrete, so I apologize in advance if this has been covered extensively already or is stickied or something.
I am looking for some help with equations for calculating the expected IBU contributions from hop additions--or perhaps more specifically, an explanation on how to use the Tinseth formula to accomplish what I want which is to use a "known" utilization percentage to calculate IBU contributions from late/whirlpool additions and subsequent hop stands. From my research, it seems that the larger-scale (relative to normal homebrew batch sizes anyway) brewers get somewhere around 15-16% utilization from their whirpool hop additions, but a reasonable estimate for homebrew-scale might be around 10% due to lesser thermal mass, lack of pump-circulated whirlpool, etc. How could one use the IBU = AAU x U x 75 / Vrecipe equation to account for IBU calculation in the aforementioned manner? I am hopeful there is some relatively easy way to convert utilization percentage into a utilization factor value comparable to those found in Tinseth's table so that I am still able to use that same equation. Hopefully that makes sense.
I have looked at the following equations as well:
IBU = weight of hops in ounces x alpha acid % x utilization % volume of final batch in gallons x 1.34*
Ounces x Alpha Acid x Percentage Utilization(boil time) divided by 7.25
While these equations give me the ability to easily input a utilization percentage, I don't like that they don't really account for factors like gravity or volume in the case of the second equation. Plus, in some cases, I get a 10 IBU or more difference when plugging the same AAU value into the Tinseth equation compared to one of the simpler ones listed above.
I am well aware there are calculators out there and tools like Beersmith to help with this kind of thing, but I am an analytical person and I like understanding the math and calculating values for myself sometimes rather than just plugging data into a calculator. I did see there is a Brewer's Friend calculator listed above the Brewing Science stickies that seemingly does what I want, so perhaps someone here is familiar with the equation(s) used there? I followed the link on that calculator to the FAQ page where it explained IBUs, but I didn't see where it got into the math side of it much.
Thanks in advance for any help and insight you can provide!
I am looking for some help with equations for calculating the expected IBU contributions from hop additions--or perhaps more specifically, an explanation on how to use the Tinseth formula to accomplish what I want which is to use a "known" utilization percentage to calculate IBU contributions from late/whirlpool additions and subsequent hop stands. From my research, it seems that the larger-scale (relative to normal homebrew batch sizes anyway) brewers get somewhere around 15-16% utilization from their whirpool hop additions, but a reasonable estimate for homebrew-scale might be around 10% due to lesser thermal mass, lack of pump-circulated whirlpool, etc. How could one use the IBU = AAU x U x 75 / Vrecipe equation to account for IBU calculation in the aforementioned manner? I am hopeful there is some relatively easy way to convert utilization percentage into a utilization factor value comparable to those found in Tinseth's table so that I am still able to use that same equation. Hopefully that makes sense.
I have looked at the following equations as well:
IBU = weight of hops in ounces x alpha acid % x utilization % volume of final batch in gallons x 1.34*
Ounces x Alpha Acid x Percentage Utilization(boil time) divided by 7.25
While these equations give me the ability to easily input a utilization percentage, I don't like that they don't really account for factors like gravity or volume in the case of the second equation. Plus, in some cases, I get a 10 IBU or more difference when plugging the same AAU value into the Tinseth equation compared to one of the simpler ones listed above.
I am well aware there are calculators out there and tools like Beersmith to help with this kind of thing, but I am an analytical person and I like understanding the math and calculating values for myself sometimes rather than just plugging data into a calculator. I did see there is a Brewer's Friend calculator listed above the Brewing Science stickies that seemingly does what I want, so perhaps someone here is familiar with the equation(s) used there? I followed the link on that calculator to the FAQ page where it explained IBUs, but I didn't see where it got into the math side of it much.
Thanks in advance for any help and insight you can provide!