Hop Recalculations

[oakbarn]

I have made reciopes and have always recalculated the ounces based upon the bought hops versus the recipe AAU valves,

I have done it for any hops regardless of the timing.

Should I be doing this for Flavors Hops (15 minutes or less) or just go with the ounces in the Recipe for Flavor and Aroma Hops?

 

[slurms]

To get the correct IBUs, you'd want to use the actual AAs of the hops you're using. If it's off by a little, my guess is it's likely not noticeable.

Though, why not just change the AAs of the hops you're using instead of the weight you're tossing in?

 

[oakbarn]

I would love to buy hops with the same AAU as the recipe, but that is basically impossible. I have to take what is available.

 

[slurms]

Sorry, I misunderstood you. You have a recipe you're working with that specifies the hops IBU/AAU.

I'd recommend downloading the BrewCipher spreadsheet. Google it and you'll find a homebrew talk post for it. You can can put your recipe in there but play with the amount (weight) and AAs of the hops to get each addition to the correct IBU according to the original recipe. It's a pretty slick program/spreadsheet.

 

[RM-MN]

I have made reciopes and have always recalculated the ounces based upon the bought hops versus the recipe AAU valves,

I have done it for any hops regardless of the timing.

Should I be doing this for Flavors Hops (15 minutes or less) or just go with the ounces in the Recipe for Flavor and Aroma Hops?

When adding the bittering hops you always want to account for the difference in the recipe AAU and the AAU values of the hops you have as this can make quite a difference in the bittering as hop alpha changes due to differences in growing conditions. The 15 minute boil for flavoring also adds bittering so if your hops alpha acid is considerably different from the recipe you would want to account for that added bittering but in most cases it could be ignored. If you use less flavoring hops to account for bitterness, think of how that would affect the flavor too. You might think about adding the flavor hops a little later in the boil instead of using less hops to get the same bittering.

 

[oakbarn]

What got me thinking is that I added a formula to calculate IBUs. Basicalily, flavor and aroma hops contribute 0 IBUs
According to the calculation I found

 

[mac_1103]

Basicalily, flavor and aroma hops contribute 0 IBUs

I don't think that's necessarily true. It depends on when you add them and at what temperatures. There are plenty of IBU calculators around that let you input the AA% and timing of the additions.

 

[tracer bullet]

I use the Brewer's Friend calculator. I kind of work the hops backwards, the latest hops (-15min, whirlpool, whatever) I go with the weight called out. I figure the IBU;s from that and then adjust the boil hops as needed, a little more or less.

Yeah, hops are never the same. Even somethign like just Cascade can vary a percent or two from brew to brew when you go to the store and get a new batch from a different farm.

I follow BF's calculations for anything regarding boiling. I figure whirlpool hops as contributing about 1/4 what I'd get from a boil, so if I whirlpool 20 minutes I put 5 minutes into the calculator for them, if that makes sense. It's not exact but it seems to be working.

 

[RM-MN]

What got me thinking is that I added a formula to calculate IBUs. Basicalily, flavor and aroma hops contribute 0 IBUs
According to the calculation I found

Hops added during the boil or even after the wort has begun to cool continue to add bittering until the temperature falls below about 170F. Hops boiled for half an hour give up about 90% of their calculated bittering.

 

[oakbarn]

I forgot the formula I used by I think it was a combination of different ones, I will try to find again, After looking at it it seemed that a 15 minute hop does effect the bitterness but not the Flame Out hop. I am wondering now if I should wait to add the aroma hops at 169 degrees?

Also, by the formula I used. 60 min vs 30 min was 76% of the bitterness (5.9 to 4.5)
at 15 min it was 2.9 so 49%. so I guess I made a misstatement in the premise. Aroma hops are the ones that do not add significantly to the bitterness.


While searching for the article that provided the formula I came across this article :

https://byo.com/article/ibu/

 

[VikeMan]

I forgot the formula I used by I think it was a combination of different ones, I will try to find again, After looking at it it seemed that a 15 minute hop does effect the bitterness but not the Flame Out hop.

Sounds like the standard Tinseth (or maybe Rager) formula. They don't count hops added at "0" minutes, because the data they used to derive the formulae didn't include flameout additions, and they ignored (from a theoretical standpoint) the fact that isomerization still happens (but slower) below boiling temps.

But there are some extended formulae available today that are more realistic.

 

[oakbarn]

Sounds like the standard Tinseth (or maybe Rager) formula. They don't count hops added at "0" minutes, because the data they used to derive the formulae didn't include flameout additions, and they ignored (from a theoretical standpoint) the fact that isomerization still happens (but slower) below boiling temps.

But there are some extended formulae available today that are more realistic.

What formulae does the Vikeman (creator of Brewcipher use)? The spread sheet is a great tool.

 

[VikeMan]

What formulae does the Vikeman (creator of Brewcipher use)? The spread sheet is a great tool.

Brewcipher uses a modified and extended Tinseth formula. So it's Tinseth, plus...

- adds IBUs for post boil hops, using my interpretation of data from a study by Mark Malowicki.
- first wort hopping
- splices a new utilization curve to the Tinseth curve above 65 IBUs, to more closely agree with measured vs. Tinseth predicted IBUs. (Above about 65 IBUs, real life utilization curves start to flatten out pretty quickly. The authors of the Tinseth and Rager formulae didn't test beers in that range.)
- enforces a cosmic speed limit of 110 IBUs.

BrewCipher also supports the Rager formula. But whichever formula is selected (Tinseth or Rager), the results show both the standard and the modified answers.

 

[CascadesBrewer]

I kind of work the hops backwards, the latest hops (-15min, whirlpool, whatever) I go with the weight called out. I figure the IBU;s from that and then adjust the boil hops as needed, a little more or less.

I do the same. I tend to think that additions at 15 minutes or less are more about the volume to get the flavors and aroma needed. I will then adjust my start of the boil addition as needed to hit my target overall IBUs.

Yes, flameout hops add some bitterness. If you are just adding 1 oz of Cascade hops and starting to cool fairly fast, you can probably just ignore this. If instead you are adding 4+ oz of a higher aa% hop like Citra, then you probably want to estimate some IBUs. I use BeerSmith and you can click a few options to carry over boil hops into the "whirlpool". I find it takes me about 3 minutes from the time I turn off the flame to when my immersion chiller is setup and starting to drop the wort temps, so I add in 3 minutes of whirlpool time.

 

[tracer bullet]

I tend to think that additions at 15 minutes or less are more about the volume to get the flavors and aroma needed. I will then adjust my start of the boil addition as needed to hit my target overall IBUs.

Exactly. Good way to describe why.