I have been playing around trying to make my own recipe on beer calculus... when I use a larger boil volume the bitterness goes through the roof.. why do ou get so much more bitterness with the same batch size but a larger boil? Meaning if I boil 3 gallons then top up to 5 gallons I get like 32 IBU...same recipe but a 6.5 gallon boil is over twice the UBU's?
Hops utilization question
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More water gets greater hops utilization. The amount of water you used was all exposed to the hops during the boil... to get your volume up you added water that was not hopped so less IBU's. The cool thing is if you get a bigger kettle you can do full boils and spend less money on hops
Less on hops, but more on boiling.The cool thing is if you get a bigger kettle you can do full boils and spend less money on hops
You could also save hops by starting the boil with only about 25% of the extract, and adding the other 75% with about 15 minutes left in the boil
-a.
a larger boil means lower wort OG, and hop utilization is mainly a factor of wort OG (not batch OG) and time.
edit: if you want to know more details, you can read this: http://www.howtobrew.com/section1/chapter5-5.html
edit: if you want to know more details, you can read this: http://www.howtobrew.com/section1/chapter5-5.html
wyzazz
Well-Known Member
Yep, full volume boils or late extract addition will greatly affect your hop utilization.
Arkador
Well-Known Member
it isn't really a matter of volume of water, but maltiness.
a 1.10 boil will get lower utilization than a 1.050 boil if all other factors are the same.
If you want to get more exact numbers, get a brew software like Brewsmith. It will calculate everything out to get you the exact number of IBUs you are looking for.
a 1.10 boil will get lower utilization than a 1.050 boil if all other factors are the same.
If you want to get more exact numbers, get a brew software like Brewsmith. It will calculate everything out to get you the exact number of IBUs you are looking for.
jkarp
Well-Known Member
Looks like lots of you are behind on your hop science. Wort gravity has no direct correlation with hop utilization. Isomerization happens just as well in a high-gravity wort as a low one. What does impact utilization is precipitates like hot break and yeast which can carry iso-alpha acids out of solution.
wyzazz
Well-Known Member
@jkarp, have any sources you could quote for that? You've piqued my interest...
jkarp
Well-Known Member
Do some searches here - there's been tons of discussion on it. First mention I'm aware of was from John Palmer on Basic Brewing's March 20th, 2008 episode. I believe someone here recently posted a link to the research paper from the same conference.
Beersmith increases the IBU's of the same batch if you decrease the amount of grist.
1. 10# maris otter, 1 oz cascade 5.5% yields (@70% Eff.) OG=1.053 IBU 20.1
2. 5# maris otter, 1 oz cascade 5.5% yields (@70% Eff.) OG=1.027 IBU 24.4
3. 2.5# maris otter, 1 oz cascade 5.5% yields(@70% Eff.) OG=1.013 IBU 26.9
Now the question is: is this an example of hop utilization changing with wort gravity or is that just a wrong conclusion. It seems with each reduction of grain and OG of wort more water is available for hop utilization and therefore higher IBU's result. So it seems true that the wort concentration would have a direct relationship to the hop utilization.
1. 10# maris otter, 1 oz cascade 5.5% yields (@70% Eff.) OG=1.053 IBU 20.1
2. 5# maris otter, 1 oz cascade 5.5% yields (@70% Eff.) OG=1.027 IBU 24.4
3. 2.5# maris otter, 1 oz cascade 5.5% yields(@70% Eff.) OG=1.013 IBU 26.9
Now the question is: is this an example of hop utilization changing with wort gravity or is that just a wrong conclusion. It seems with each reduction of grain and OG of wort more water is available for hop utilization and therefore higher IBU's result. So it seems true that the wort concentration would have a direct relationship to the hop utilization.
jkarp
Well-Known Member
Neither. It's an example of a program using the best data available at the time it was written. There are so many variables involved in hop utilization in wort, it's unlikely anyone will ever tackle researching a new formula. Palmer himself said even though the current formula we use is wrong based on this new understanding, it's still "good enough". He's of course right as there's no human perceptible difference in your examples. A 20.1 IBU beer will taste just like a 26.9 one.
homebrewer_99
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This is totally against everything I've ever read on the subject. In this case wort gravity and density mean the same.
A wort's high density results in a lower hop bitterness extraction...it's in Papazian's TCJOHB.
I like to picture it as higher density leaves less water for the hops to utilize. Lower density more water to utilize -> higher IBU ...
jkarp
Well-Known Member
Which was written when? Brewing science evolves. Can't deny the research and published papers. Palmer admitted he was wrong, right down to his very definition of what an IBU is.
Yes, but how do we know that he was right to be wrong? Maybe he's wrong and was right all along.
D'ohhhh!!... every time I learn something new, it pushes some old stuff out of my brain!!
mparmer
Well-Known Member
I'll be willing to taste test any beers you guy's want to send me with different IBU's, and I promise I will give you the most scientific replies I can... ;-]
Wow that podcast was way too long to listen to all of, but good to know they changed the calculations of it. However, our tastes are already associated to the IBUs we have been using, so does it really matter if the actual values were off?
