Author Topic: Beersmith Hop ulilisation calculation and boil volume  (Read 17110 times)

BeerMonster

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Beersmith Hop ulilisation calculation and boil volume
« on: June 03, 2009, 02:08:20 AM »
Im having trouble making sense of the IBUs calculated by Beersmith for a given boil volume versus recipes from outside of beersmith.

Im making Port O’ Palmer Porter from page 136 of How to Brew 3rd edition, using the extract method plus steeping grain (as per the recipe).

It calls for :

14g Horizon 12% 60 mins 21 IBU
21g Willamette 5% 40 mins 12 IBU
14g Willamette 5% 20 mins 5 IBU.

Total IBU 38.

Putting this into Beersmith with a batch size of 19L and a boil volume of 19L gives 38 IBU. All is well.

But I only have a 10L stockpot. So I change the boil volume to 9L. Beersmith recalculates the IBU to be 21.

I initially think this is realistic as there will be poorer hop utilization with less boil volume. Im just about to up the hop weights by around 100% to get BeerSmith to calculate the final IBU to be 38.

But then I notice the recipe uses a boil volume of 11.4Litres and not 19L. This implies the recipe would give 21 IBU (or thereabouts) despite the book saying it is 38IBU.

So how can Beersmith calculate an IBU of 21 with a boil volume of 9L, yet the recipe calculates 38IBU with a boil volume of 11.4L and gets 38IBU ? Clearly I have entered the initial data correctly since Beersmith agrees with the recipe for the hop quantities used when the boil volume is the same as the batch volume.

One of them has to be wrong, or else Im missing something. 38IBU versus 21IBU is significant in my opinion. Although clearly Im just learning and haven’t really used Beersmith in anger yet – so there’s plenty of scope for a decent explanation and education here.

Colin
« Last Edit: June 08, 2009, 04:51:13 PM by BeerMonster »

dhaenerbrewer

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Re: Beersmith Hop ulilisation calculation and boil volume
« Reply #1 on: June 03, 2009, 06:32:27 PM »
That all sounds very odd. Typically with a smaller wort volume you should get better utilization, as you would normally have a more vigorous boil. I don't see how decreasing the boil volume would decrease the IBU's. For all intents and purposes it should increase the IBU's, as you will have a higher mg alpha acid/liter ratio.

Putting that recipe into beersmith, I get 38 IBU's with a 19L batch size. When I drop it down to a 9L batch size, I get 49 IBU's. Not sure what's going on there.

Darin


BeerMonster

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Re: Beersmith Hop ulilisation calculation and boil volume
« Reply #2 on: June 04, 2009, 05:16:54 AM »
Well I dont understand that ! I havent, that I know, altered anything to do with hop calculations in Beersmith. But something is different between your setup and mine then.

Would you try uploading my recipe (attached) and see if its the same ? Ignore everything but the ingredients, that's just a cut and paste from a random recipe. As it is it gives 37.5IBU with a 20L boil and 21.2IBU with 9L boil. Well, it does for me anyway !

Offline UselessBrewing

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Re: Beersmith Hop ulilisation calculation and boil volume
« Reply #3 on: June 04, 2009, 07:40:58 AM »
There must be something in your setup that is causing this. I opened your recipe and played with the volumes, and I get an increase in IBU when Decreasing the volume also. I will play with it to see if I can find the issue.

Cheers
Preston
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BeerMonster

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Re: Beersmith Hop ulilisation calculation and boil volume
« Reply #4 on: June 04, 2009, 04:22:25 PM »
OK, thankyou very much. At least that narrows it down somewhat.

Im no expert brewer, far from it. But I thought a higher gravity gave lower hop utilisation ?  In layman's terms, less water to suck out the hop flavour ! And to my tiny mind boiling in 20L of water instead of 9L should give a lower gravity boil, ie much more diluted, less dense, less gravity etc etc. and therefore HIGHER hop utilisation at the higher boil volume since there's more (clean) water with which to extract the hop goodies ? So I hadnt thought anything strange about my setup until I started questing it against the recipe - and now others' setups.

Also as far as I know, everything is set to defaults in beersmith excepting I added my own equipment to reflect the 10L pot.

Anyway - the point of this post - here's the exact same recipe with a boil volume of 9L giving an IBU of 21.2 in my setup. Just in case it helps locate the issue.

Offline MaltLicker

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Re: Beersmith Hop ulilisation calculation and boil volume
« Reply #5 on: June 04, 2009, 06:30:44 PM »
Is there a typo somewhere in the initial post?  Your equipment setup has the mash-tun volume at 2.64 gallons, or about 10L.  If your only pot is 10L, then you cannot physically have a boil volume of 19L, right?  Even with a 19L pot, your boil volume will be less than the pot's maximum. 

The batch size can be 5 gallons due to the added top-off water poured in the fermentor (post boil), but your boil volume in a 10L pot might be something like 7L?  At least until the hot break is safely over, then you could add some water back to maximize the boiled amount, which may help hops utilization a little. 

Lots of brewers do 5 gallon batches in 19L pots, adding about 2 gallons of clean water post-boil.  So do you typically add about 3.5 gallons of water post-boil?  If so, that's a very concentrated boil, and I could see BeerSmith having trouble with the math unless your get your equipment setup figures exactly down. 

Hope that helps.  Re-post if I read that entirely wrong.

dhaenerbrewer

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Re: Beersmith Hop ulilisation calculation and boil volume
« Reply #6 on: June 04, 2009, 09:27:21 PM »
The amount of water in your wort really has nothing to do with utilization. Hops are not very soluble in water, and it takes a lot of heat for isomerization to occur. The presence of sugars and lipids makes it more difficult to isomerize the alpha acids, so therefore a higher gravity wort will result in lower utilization. You were right about the gravity, but not the reason for the lower utilization with higher gravity. Conversely, while researching this topic I learned that the presence of Magnesium ions acts as a catalyst for isomerization. So therefore, you can attain a higher utilization % with higher Mg++ levels. Though you don't want to excedd 65 ppm, as it can become harmful to yeast in those concentrations. I have not tested this, and have not seen any empirical data to back it up; but I did find it from several different sources.

Darin

BeerMonster

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Re: Beersmith Hop ulilisation calculation and boil volume
« Reply #7 on: June 05, 2009, 03:44:34 AM »
If your only pot is 10L, then you cannot physically have a boil volume of 19L, right?  Even with a 19L pot, your boil volume will be less than the pot's maximum. 

Hope that helps.  Re-post if I read that entirely wrong.

Yes you're right - my pot is 10L, so the boil would be 9 or even less. I havent got down to accurately putting the data in, since I cant make sense of it when I make large adjustments.

So yes, my pot cannot have a 19L boil. But if I change my pot to, say, a 30L one then the same observations are true regarding the IBUs - namely they are 38 for a 9L boil and 21 for a 19L boil, yet the Dave Palmer recipe says 38IBU for a 11L boil.

So your point is quite valid - but consider my post re-posted with a 30 or 40 L pot (or whatever) that can contain a 20L boil ..... my observations remain (not that they're correct, there's obviously something amiss !)


Offline MaltLicker

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Re: Beersmith Hop ulilisation calculation and boil volume
« Reply #8 on: June 05, 2009, 05:46:06 AM »
Yes you're right - my pot is 10L, so the boil would be 9 or even less. I havent got down to accurately putting the data in, since I cant make sense of it when I make large adjustments.

Since your pot is half the size of Palmer's, I'd start with entering your exact size and water capacities.  Those measurements are "fixed" in the short-term.   There are lots of dependent calculations that happen inside BeerSmith, so it's usually best to verify and enter the known factors first. 

BeerMonster

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Re: Beersmith Hop ulilisation calculation and boil volume
« Reply #9 on: June 08, 2009, 04:59:18 PM »
Well that in essence is my problem.

I start with a known recipe (ie Porter's as per my first post) and a known IBU of 38 according to Porter. 

Entering it into Beersmith I get the predicted IBUs to be 38  if, and only if, I use a boil volume of 20L.

But Porter's recipe uses a boil volume of 11.4L.

According to Porter's recipe (using the hops in my first post) that would give an IBU of 38 for a boil volume of 11.4L.

According to Beersmith (using the same hop list) it would give an IBU of 21.

My point is, one of them is wrong. Given Ive made Porter's recipe and it's indeed very nice, Im thinking something is wrong with my Beersmith setup since 21 IBUs is unlikely to give a nice tasting porter (or anything some to that).

Dunno if Im making my point too well here. Im just saying surely a recipe from the famous "How to Brew" should match at least approximately the IBUs predicted by Beersmith for the same boil volume ?

 

Offline Wildrover

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Re: Beersmith Hop ulilisation calculation and boil volume
« Reply #10 on: June 08, 2009, 07:43:56 PM »
Wrong might be a subjective term here.  I am no expert here but I believe there is more than one way to calculate hop utilization (e.g. Rager vs. Garetz).  I know I've heard Jamil (who I would bet uses the same method as Palmer) actually name the method he uses to calculate hop utilization. I'm not sure which method BS uses to calculate this but the answer may be as simple as Palmer and BS calculating hop utilization differently.  

addendum:  Well, I got curious so I entered the recipe into BS just as Palmer has it.  I entered it as an All grain batch assumed a 75% efficiency as Palmer does and a batch volume of 5 gallons, again as Palmer does.  

The IBUs BS calculates is 38.8 which is obviously very close to the 38 listed in the book.  So, I would suggest making sure the grain bill is the same, believe it or not this can make a difference and that the hop AA's you are entering aren't different from what Palmer lists (BS and Palmer don't agree on the AA's for all the hops).  I'd also make sure you've accounted for your efficiency (assuming you are making an all grain batch).  If your efficiency is lower and you don't adjust for this, your hop utilization will be greater.  

Try entering everything in just as Palmer has it and make sure the assumptions are the same and see what that tells you.  If you're not close then I'm not sure what to tell you?  If you are, then start changing the variables one at a time to more closely match your system.  See what changing each variable does to that IBU number.  That way, I'm guess you'll be able to narrow down what it causing the issue.

Addendum Addendum:  I looked at your Porter recipe and you don't have the right hops or AA in there.  You have cluster and an AA at 5.5 and not Horizon which should have an AA around 12. Also, the AA levels of your Willamette are low compared to Palmer who has his at 5.  Change these and my guess is your problem will be solved
« Last Edit: June 08, 2009, 08:12:01 PM by Wildrover »

BeerMonster

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Re: Beersmith Hop ulilisation calculation and boil volume
« Reply #11 on: June 08, 2009, 09:04:26 PM »
Wildrover - thanks for your time looking at this. Maybe Ill get to the bottom of it !

Most important first :

Quote
Well, I got curious so I entered the recipe into BS just as Palmer has it.  I entered it as an All grain batch assumed a 75% efficiency as Palmer does and a batch volume of 5 gallons, again as Palmer does.  

The IBUs BS calculates is 38.8 which is obviously very close to the 38 listed in the book.  

But what boil volume did you use when you did this ? If you used 18.9L / 5 gallons then your Beersmith would roughly agree with mine with an IBU of around 38 IBU. Im guessing this is what you did.

But this wouldnt in fact be in agreement with Palmer because he uses a boil volume of 3 gallons or 11.4L. To quote his text (p136 or here http://www.howtobrew.com/section2/chapter13-3.html where he isnt quite as explicit but note he simply brings his 3 gal wort to the boil - no water added ie boil volume 3 gal or thereabouts) :

Quote
Add water to bring the wort volume up to 3 gallons (11.4L). Bring to the boil. Add hops as per recipe.

Assuming this is what you did (ie used a batch of 5 gal, and a boil 5 gal) what happens if you change the boil volume to 11.4L (or 3 gallons) as per Palmer ?

If your Beersmith is like mine that will give you an IBU of around 22, which is miles away from Palmer's prediction.

PS :

Addendum Addendum:  I looked at your Porter recipe and you don't have the right hops or AA in there.  

yes, you're right, I posted the recipe substituted with the hops I can get hold of, but adjusted the weights for the same IBUs but using the diffferent AAs. If I use the exact same hops as Palmer it gives a very similar result of 37IBU for a 18.9L batch but again only using a 18.9L boil. Using the actual boil volume of 11.4L still gives 22IBU or thereabouts - ie still an almost identical and very significantly different IBU prediction than that of Palmer's recipe.

When you say am I doing an all grain - well Im doing it as per Palmer using 3Kg of palm malt extract, so in fact no, Ive entered it as an extract recipe.
« Last Edit: June 08, 2009, 09:08:58 PM by BeerMonster »

Offline Wildrover

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Re: Beersmith Hop ulilisation calculation and boil volume
« Reply #12 on: June 08, 2009, 10:20:05 PM »
BeerMonster,

I assumed this was an all grain batch since this is the AG board and I was looking at the recipe on pg 223-224 where they list the all grain option, not pg 136 where he just has the partial mash version.

Anyway, I can get mine to work out just fine using a boil volume of 3 gallons.  I opened your attached recipe again and worked with that.  The things that i might suggest are:

Check your efficiency, even with a partial mash, this still has an influence.  Palmer assumers 75% so make sure your brewhouse efficiency is set to 75%.

Also, the AA in the hops you have listed are not the same.  Again, if you delete your cluster which is listed at 5.7 and add horizon which is at 12% this will make a huge difference in an of itself. 

Also, raise the AA on the Willamette to 5% from the 4.8 that you have listed and those few things should bring you up to 40.3. 

In summary, I have my BS set to 75% efficiency.  A five gallon batch with three gallons boil volume.  I also changed the hops to match Palmer's as well (and this I think is most important) made sure the alpha % also matched what he listed. 

This should fix it for you.

Of course, when you make the recipe its more important that you are entering the hops you have and using their alpha percentages but for now, to get your problem worked out, try to make those quick changes and see if that doesn't fix it for you.   

BeerMonster

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Re: Beersmith Hop ulilisation calculation and boil volume
« Reply #13 on: June 09, 2009, 01:07:44 AM »
Wildrover,

thankyou again for your time here.

Well I posted here under the "advanced" topic rather than all grain ... in fact Im about to do my first all grain when I can be confident I have mastered Beersmith sufficiently !

OK, attached is the Palmer's porter recipe as per p136, all ingredients correct according to me that is.

Ive also attached two screenshots of the recipe in Beersmith. One shows 37 IBU (near enough what we expect) for BV 18.9L. The second shows IBU 27 for BV 11.4L. Both have efficiency of the default 75%. So Im still wrong at 27 IBU, but I dont know why !

Interestingly the 11.4L boil isnt 22 any longer, but 27. Still not the same as Porter, nowhere near, however for reasons I absolutely do not understand the final IBU has changed with the use of a different alpha and weight all be it for the same individual IBU for that hop addition. So this is as you said it would be ... but Im still not right at 27 IBU and a 11.4L boil ?

So with the attached recipe, what IBU's do you get for the two Boil Volumes of 18.9 and 11.4 L ?

 
« Last Edit: June 09, 2009, 04:05:37 AM by BeerMonster »

BeerMonster

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Re: Beersmith Hop ulilisation calculation and boil volume
« Reply #14 on: June 09, 2009, 01:21:54 AM »
Couldn't upload the screen shots. They're here http://picasaweb.google.com/tezfwit/Beer#5345224196647817586 instead.