Full Boil vs. Partial boil Hops utilization

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Grinder12000

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I'm surprised at how much extra hops you have to add when doing a partial boil.

I was playing with Beer Smith and when I flipped to a partial boil my hops utilization plummeted. So I increased the bitterness to the desired IBU and it was ABOUT 50% more hops needed.

YIKES - no wonder my brews always tasted a little more malty then I thought.
 
Yes, 'tis sad with the cost of hops nowadays.

Therefore, I shall charge you with a crusade. You must seek out the Holy Turky Fryer. :p
 
If you are using extract, or PM brewing, you also want to take into account that the late addition method does add some IBUs back.
 
I was calculating about a 38% gain in IBU by using a 'full boil' gravity when doing extract batches. This is an important money saving tip in today's times. With hops going for $32/pound this is worth paying attention to.
 
I'm surprised at how much extra hops you have to add when doing a partial boil.

I was playing with Beer Smith and when I flipped to a partial boil my hops utilization plummeted. So I increased the bitterness to the desired IBU and it was ABOUT 50% more hops needed.

YIKES - no wonder my brews always tasted a little more malty then I thought.

That's not entirely true. Based upon my brewing technique, using 1 gal of water to 1 lb of malt I actually use fewer hops. Rarely do I ever use over 4AAs in a 5 gal batch with 6 lbs of malt. My Hefe Weizens only use 3AAs.

If you do a small boil and add all of the malt then, yes, you get very lousy utilization. :mad:
 
I've been doing 2.5g boils with 1lb for 60 min and the rest at 15min. Normally I'll have 3.5 to 4lbs of grain in a mini mash.
 
if you are doing partial mash with a partial boil, you can simply wait until the end of your boil to add your extract, then you will get better utilization from your hops ;)
 
Yes, 'tis sad with the cost of hops nowadays.

Therefore, I shall charge you with a crusade. You must seek out the Holy Turky Fryer. :p

And so the lad said:

"Seek ye the holy fowl cooker, so that it may be brewed.
Two cubits across and three high, no less shall ye seek.
Appoint it with the ball valve of mercy, so that ye may drain it well.
Let not the oil contaminate it, nor let it runneth over."
 
"Seek ye the holy fowl cooker, so that it may be brewed.
Two cubits across and three high, no less shall ye seek.
Appoint it with the ball valve of mercy, so that ye may drain it well.
Let not the oil contaminate it, nor let it runneth over.

BRAVO!!! THAT is blog worthy
 
As BarleyWater informed me.

When doing a partial-boil and late extract method, you can't rely on beersmith, or similar program to calculate the IBU's, because it doesn't take into account the water you will be topping off with.

So, if you are using Beersmith, or similar program when creating a recipe, and say for example your aiming at 30 IBU's, you actually will want to aim for 60, because if you aim for 30, after top off you will only get 15.
 
Here is an easy rule of thumb if your not doing a full-boil.

You can assume 50% of the total amount of IBU's calculated using a program like beersmith. So, if you end up topping off with 2.5 gallons of water, you will end up with 50% of what the program orginally calculated. Also, you must always go by 100 IBU as a limit. You can't calculate 50% of say 150 IBU's and expect 100 total IBU's, because 100 IBU's is the total limit regardless of brewing methods.
 
I just want to make sure i'm understanding. Beer Alchemy, (which most people don't use since they don't have mac) does take into account the amount of h20 in the pre boil, post boil, transfer and water used to top off. Changing any of those numbers does change the number of IBUs projected.

Are you saying that the numbers can't be trusted because of a flaw in the brewing softwares? I just want to make sure i understand. I mean i understand you are diluting down a partial boil and that changes how hops are utilized and the concentration of the IBUs, but i don't understand where the softwares start to tell you the wrong information if it takes into account how much water you top off with.
 
I agree. Beer tools does have a button that calculates IBU's and when I go from a full boil to a partial boil it takes an appropriate number of IBU's away!

But you guys are saying it's wrong?
 
I agree. Beer tools does have a button that calculates IBU's and when I go from a full boil to a partial boil it takes an appropriate number of IBU's away!

But you guys are saying it's wrong?

Yes. So is the one in Beer Smith. It lowers the IBU, but only as a result of the increased gravity of a partial boil, none of the equations are set up to take in dillution of the wort. You really can count on getting about half of what it tells you. Read the link I posted earlier, its all in there.
 
This is interesting... I never thought of this before. Is there a way to set up your recipe in BeerSmith to correctly calculate IBUs in a partial boil?

If not, I don't think I am following the solution. Is it as easy as formulating the recipe in BS to have double the IBUs I want? (reading other link now...)
 
This is interesting... I never thought of this before. Is there a way to set up your recipe in BeerSmith to correctly calculate IBUs in a partial boil?

If not, I don't think I am following the solution. Is it as easy as formulating the recipe in BS to have double the IBUs I want? (reading other link now...)

How much water will you be topping off with?

If 2.5 g, then assume 50% of the calculated IBU's, with 100 IBU's as the limit.
 
Thanks, I am topping off with 2.5.

One more question: In BeerSmith for my recipe I am brewing on Saturday I have the batch size set to 5 gal., and the boil volume set to 3 gal. In this setup my recipe shows 27.1 IBUs. If I set the boil volume to a full boil, it shows 41 IBUs.

The 41 IBUs is what I am looking for in the finished wort, so... which way should I configure the boil volume and then add hops to double my IBUs?
 
First off, are you doing a late extract addition? If so, as long as you are adding about half of the extract at the end, you can then set it to full boil and get it to 82 IBUs. Since half of the liquid into the fermenter will be water, you are getting half those IBUs, so 41. Keep the flavor and aroma additions the same, and add hops to the bittering addition to make up the difference and it won't affect the hop profile that much.

The first way you had it, showing 27, takes into account an very high wort gravity in the boil kettle, so it brings your IBUs down to 27 IN THE BOIL KETTLE, once you add 50% plain water to dilute, that would bring you down to 13.5 IBUs.

Partial boils suck, turkey fryers are cheap right now too.
 
This is an interesting conversation, so I thought I might ask a question or two. From what I understand in these posts, partial boils and partial mash are the same? If not what are the differences? I think your IBUs increase the longer you boil (correct me if I'm wrong), so is the reason you are losing IBUs because you don't boil your wort as long? Why wouldn't you do a full length boil all the time to get the most out of your hops?
 
This is an interesting conversation, so I thought I might ask a question or two. From what I understand in these posts, partial boils and partial mash are the same? If not what are the differences? I think your IBUs increase the longer you boil (correct me if I'm wrong), so is the reason you are losing IBUs because you don't boil your wort as long? Why wouldn't you do a full length boil all the time to get the most out of your hops?

No, you boil for 60 minutes during a partial-boil. A partial-boil is when your not boiling the full 5 g of wort.
 
This is an interesting conversation, so I thought I might ask a question or two. From what I understand in these posts, partial boils and partial mash are the same? If not what are the differences? I think your IBUs increase the longer you boil (correct me if I'm wrong), so is the reason you are losing IBUs because you don't boil your wort as long? Why wouldn't you do a full length boil all the time to get the most out of your hops?

Partial boil = not boiling the entire volume of wort, thus having to top off with plain water.

Partial mash = using some base grains, and some extract to achieve your desired gravity.

Late extract addition = adding half of your extract at the end of the boil to aid in hop utilization. (you didn't ask, but I thought I would throw it in anyway)

You do get more IBUs the longer you boil to am extent. After about 60 minutes you are getting little to nothing else out by boiling longer. In any of the methods listed above, all of which can be used indepedently or collectively, you would still boil for a full hour. The reason for losing the IBUs is adding 50% water that contains no IBUs, and having an inceased wort gravity due to the concetrated sugars in the partial boil (although this second point point is of some contention).
 
So - I'm confused now - how is the best way to figure out IBU's in a partial boil.

Did I read that you CAN'T have greater then 100IBU's??

Walk me though this.

Beersmith says I have 40IBU in a FULL boil - yet I do 2.5g partial boil with a late addition of Extract at 15 min. How do I make up for the loss of IBUs
 
I've been struggling with this too, but I think I can answer your questions.

You cannot have greater than 100 IBUs in any amount of wort you boil. When you max out at 100 in a partial and top off with plain water, you are diluting the IBU concentration, and the number goes down accordingly.

I am trying to correct a recipe that is in a similar situation to what you are describing, and all I did was modify my hop schedule to produce 82 calculated IBUs in BeerSmith instead of the 41 I want in the finished beer (based on a 2.5 gal. top off). If I followed this thread right, and the discussion is correct, this should be all that is necessary.
 
This is all just a bit confusing for me too... So, if you do a partial (2.5g) boil with 1/2 late extract addition, the IBU's would be roughly equivalent (not taking in to account any boil time for the extract added late) to a full boil with no late extract addition right?
 
Would someone mind explaining why late extract addition increases your hops utilization?

...I actually thought it was the other way around.
 
Would someone mind explaining why late extract addition increases your hops utilization?

...I actually thought it was the other way around.
Hop bitterness extraction actually depends on the density of the wort.

If you do a partial boil with all your malt then the desity (gravity) is too high resulting in low extraction. Too much water/low malt will result is more bitterness.

There's a chart in Papazians TCJOHB that recommends a mean/average wort gravity of 1.040 for 1 gal of water and 1 lb of DME with a recommended hop amount.

BYO uses a gravity of 1.045 for the same 1 g water and 1 lb DME.
 
SO - if I take a gravity reading preboil (after mash and extract additions) and it is 1.040ish - I'm good to go! otherwise tweak. thanks
 
The answer!!! The Texas two Step!!

Podcast about 1/2 way through.

Brew 1/2 of you batch with 1/2 of your ingredients - cool it and pitch the yeast. THEN - brew the 2nd half of you batch, col it and combine it with the 1st batch.

Another way is as mentioned - brew 1/2 the batch but use only 1/2 the extract - as mentioned try to get the OG at 1.040. Hop utilization wiltt be perfect - the PROBLEM is that then you dilute it and your hops will be cut in half.

It is not mentioned what happens of you use twice the amount of hops in the 1/2 boil.

This is why IPA's are very hard to make in a partial batch.
 
It is not mentioned what happens of you use twice the amount of hops in the 1/2 boil.

This is why IPA's are very hard to make in a partial batch.

You will get twice the IBUs up to 100, after that it's just adding vegetable matter to your boil pot. Determine how much flavor and aroma additions there should be, and add to your bittering addition to achieve the desired IBUs.

This is why I got a turkey fryer and a big kettle, my IPAs sucked..
 
Anybody know if Beer Calculus is any good for this calculation? It takes into account the boil size, and when I just dropped a recipe from 3g boil to 2.5g boil it dropped the IBU a few points. I also entered the hops first, then the malt. It showed the IBU dropping as I added malt. All of this makes me think that maybe it is a good toil for those concerned about this. ANy thoughts?
 
If it is ANY help - I partial boil and will do the late extract addition. What this does is give me a GOOD hops utilization for that 2.5g boil. PROBLEM is then dilution which cuts it in half. So - I'm upping the hops from 1oz to 1.5oz oo my stout today. I think the more hops you are using the bigger problem is it.
 
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