Hop utilisation

The Homebrew Forum

Help Support The Homebrew Forum:

Braufather

Landlord.
Joined
Aug 23, 2016
Messages
1,571
Reaction score
545
Location
NULL
Hop utilisation.

Not sure what I’m doing wrong but getting some crazy numbers from brewers friend.

I’ve been advised that you get about 50% hop utilisation at 90c. so I assume this means you can add double the hops if its for the same time period and get same ibu but more flavour.

However Instead of adding more hops I was looking extending the hop stand. So given 50% utilisation, would 20 mins at 90c give same ibus as 10 mins at 100c? or is the extraction not linear time wise?



Brewers friend must be miles out it gives over a 100 ibus for a 50% utilisation hop stand at 90c for 10 mins?



Help appreciated chaps






1643305166000.png
 
Joined
Aug 26, 2019
Messages
4,806
Reaction score
4,686
Location
Warrington
You are not reading it correctly I think the 50% is half the utilisation you would get at 100C for the same time period. So how I work it is if you want 30m hop stand at 90C, then firstly for your hops put in 30m at boil and this gives you a utilisation of say 25%. Then switch to whirlpool and enter 12.5% in the utilisation box.
 

the baron

Moderator
Staff member
Moderator
Joined
Oct 13, 2013
Messages
4,574
Reaction score
3,054
Location
castleford
You would get 3.9% utilisation @90c with my calc on brewers friend unfortunately I can not see your screen shot as I am having to use ny old glasses while awaiting new ones :laugh8:
As CC said are you sure that whirlpool has been selected or reset it all and re input the recipe
 

Braufather

Landlord.
Joined
Aug 23, 2016
Messages
1,571
Reaction score
545
Location
NULL
Cheers chaps, although I’m still not sure I’m following how it works. I’m going to read this again in the morning!
 

Braufather

Landlord.
Joined
Aug 23, 2016
Messages
1,571
Reaction score
545
Location
NULL
You are not reading it correctly I think the 50% is half the utilisation you would get at 100C for the same time period. So how I work it is if you want 30m hop stand at 90C, then firstly for your hops put in 30m at boil and this gives you a utilisation of say 25%. Then switch to whirlpool and enter 12.5% in the utilisation box.

ok it looks like I misunderstood what hop utilisation is. I assumed it would be 100 per cent at 100c and start from there. So it looks like it’s never above 25 percent even at a 60 mins in the boil. So I can work it out from the boil calculter.

still don’t see the point of of the hop stand calculator though, you’ll know the figures already, As you’ve had to use the boil calculator to get them! its the IBUs you are after anyway and I’ll just half the results from the boil input ( based on 50% efficiency at 90c)
 

dmtaylor

Well-Known Member
Joined
Jul 16, 2021
Messages
120
Reaction score
88
Location
Two Rivers, WI, USA
The 50% utilization is totally wrong, it never gets that high, max is closer to 35%, and utilization is definitely not linear with time or temperature either. It isn’t far from a square root relationship vs. time, however. I’ve developed the following equation which takes all these things into consideration in a very simplified format. This is an approximation that will come within 5-10 IBUs of Tinseth. Try it out and see.

IBU = oz * AA% * [sqrt(5*Boiltime)/V + sqrt(2*HStime)/V]

where
V is post-boil volume (in gallons),
Boiltime is in minutes, and
HStime is post-boil hop stand time in minutes where it hangs around between about 150-190 F (65-90C).

(Sorry for my Yankeeism, my equation uses ounces and gallons. If you like grams, then divide by 28.35. Liters, multiply by 3.79.)

For multiple hop additions, put each one in separately, run the calc, then add up the total IBUs. It's not perfect, but it's pretty darn close for standard gravity worts of 1.050-1.060. At higher gravity (e.g., >1.080), change the sqrt 5 to 4 instead, and sqrt 2 to 1.5. At low gravity (e.g., 1.035-1.040), change the 5 to a 6, and the 2 to 2.5. Pretty close, and not too hard to memorize.

Keep in mind also, that regardless of amount of hops used, you'll never get more than 90 to 100 IBUs by conventional methods. It is simply a fact of physical chemistry. If you use more hops than you need for that IBU level, you just waste hops and beer (the extra hops permanently soak up extra wort or beer).
 
Last edited:

Braufather

Landlord.
Joined
Aug 23, 2016
Messages
1,571
Reaction score
545
Location
NULL
HStime is post-boil hop stand time in minutes where it hangs around between about 150-190 F (65-90C).

Interesting, as i understand it at 90C you would get half the utilisation than you would at 100C but at below 78 it would be closer to zero in terms of ibus? so big differences in this range?
 
Joined
Feb 7, 2021
Messages
297
Reaction score
588
Location
Leamington Spa
ok it looks like I misunderstood what hop utilisation is. I assumed it would be 100 per cent at 100c and start from there. So it looks like it’s never above 25 percent even at a 60 mins in the boil. So I can work it out from the boil calculter.

still don’t see the point of of the hop stand calculator though, you’ll know the figures already, As you’ve had to use the boil calculator to get them! its the IBUs you are after anyway and I’ll just half the results from the boil input ( based on 50% efficiency at 90c)

I've heard of people using hops for multiple brews as the utilisation is sufficiently low that even on the second or third time through there are still oils being extracted so I'd say 25-30% is probably a reasonable number.
 
Joined
Feb 7, 2021
Messages
297
Reaction score
588
Location
Leamington Spa
Interesting, as i understand it at 90C you would get half the utilisation than you would at 100C but at below 78 it would be closer to zero in terms of ibus? so big differences in this range?

Be careful not to confuse hop utilisation (the amount of oils being extracted from the hops) to alpha acid isomerization (the conversion of alpha acids into bitterness).
 

dmtaylor

Well-Known Member
Joined
Jul 16, 2021
Messages
120
Reaction score
88
Location
Two Rivers, WI, USA
Interesting, as i understand it at 90C you would get half the utilisation than you would at 100C but at below 78 it would be closer to zero in terms of ibus? so big differences in this range?

Ah... I think we may be talking apples and oranges in some respects. The term "utilization" is a very specific term when calculating IBUs. You are using the same term for two totally different uses. You cannot enter 50% utilization in the software in the manner you did above, that's not what the software intended. On the other hand, with respect to hop stands, you are also kind of on the right track, in that a longer hop stand can give you about the same IBUs as if boiled for half the time. However, this is only a very rough approximation and not exact, and varies considerably with temperature (like if the temp slowly were to fall from 90 to 80 to 75C). Also, isomerization (this is also a key term) doesn't just go away below say 78C or whatever. It's a curve that continues way down to closer to 50-55C before it really drops off. Temperature is indeed a big factor for hop stands. In short, as long as you keep the hop stand hot without boiling (80-90C or whatever), then it will add IBUs in a manner similar to what you have imagined. It's just... difficult to calculate accurately. Try my formula if you like and see where it takes you, versus software which I don't think you were using quite right. Don't enter any "utilization" numbers. Just leave it to the defaults.
 
Top