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IBU Scaling in a concentrated wort?

Post #1 made 14 years ago
by stux
So,

If we wanted 20L of wort at OG (ie not concentrated) and we hopped that to 20IBU, that would be one thing,

now say we had a concentrated wort prepared to 15L, and we wanted to post-boil dilute this back to 20L, would that mean that actually you need to aim for 33% more IBUs during the boil, so that post boil you get 20IBU?

15L at 26.66 IBU + 5L of water = 20L at 20IBU?
Fermenting: -
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On Tap: NS Summer Ale III (WY1272), Landlord III (WY1469), Fighter's 70/- II (WY1272), Roast Porter (WY1028), Cider, Soda
Next: Munich Helles III

5/7/12

Post #2 made 14 years ago
by Ralph
I calculate IBUs based on the diluted volume, when designing that's the figure I work with. Calculating bitterness for the actual 15L batch would be 20/15 * IBU target. Well that's how I'd do it, but you'll probably never make a meaningful assessment of the 15L's bitterness apart from when its diluted, that's why I don't bother. However there are some issues with respect to utilisation at the higher gravity during the making, but to be honest I've found that it just isn't worth getting excited over at Maxi-BIAB scale for non- exotic, garden- variety beers.
[center]Give me a beer and I will move the world. Archimedes[/center]

Post #3 made 14 years ago
by PistolPatch
Just had a look at this while Ralph must have been writing the above :). I too, never worry about adjusting for this. For example if I needed 50 grams to do a normal 20 litre batch then I'd just use 50 grams in the diluted boil.

But, in your scenario, if you want to get it accurate, it looks as though you have to increase your hop bill by 10%. If you don't, your bitterness will drop by 10%.

:peace:
PP
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Post #4 made 14 years ago
by stux
I believe I've solved the problem :)

The trick is to calculate based on the diluted volume but using the concentrated gravity :)
Fermenting: -
Cubed: -
Stirplate: -
On Tap: NS Summer Ale III (WY1272), Landlord III (WY1469), Fighter's 70/- II (WY1272), Roast Porter (WY1028), Cider, Soda
Next: Munich Helles III

5/7/12

Post #5 made 14 years ago
by Ralph
One method bandied about for proper hops utilisation is to increase IBU for each addition by 10% per 0.010 over 1.050. The Maxi-BIAB boils I do generally end between 1.065 and 1.080, so that's potentially 30% more hops. However, IIRC I've never adjusted additions up on account of unexpectedly- low bittering, usually the other way around if anything. I'd say though that I seldom make highly- bittered beers, so that may need to be considered.
Also, keep in mind that when considering hops utilisation adjustment for higher- gravity boils, it seems to just revolve around bittering, not the later additions, however I'm yet to actually confirm that in the wild.
[center]Give me a beer and I will move the world. Archimedes[/center]

Post #6 made 14 years ago
by stux
The Tinseth formula has a part for "Wort Bigness" which takes care of scaling up the hop requirements as the gravity increases.

The probem is we don't know if this is correct in a concentrated scenario. But in theory, it should be.

The concern is what you have said about "However, IIRC I've never adjusted additions up on account of unexpectedly- low bittering"

BUT do you No Chill? No Chill could be compensating by perhaps increasing hop utilization by 30% ;)
Fermenting: -
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On Tap: NS Summer Ale III (WY1272), Landlord III (WY1469), Fighter's 70/- II (WY1272), Roast Porter (WY1028), Cider, Soda
Next: Munich Helles III

5/7/12

Post #7 made 14 years ago
by Ralph
Yeah, some very good points stux!

Occasionally I'll no- chill if the circumstances dictate, in the vast majority of cases I'll chill in- kettle, however I don't adjust hops for no- chill either*. It could be though that no- chilling may offset poor hops utilisation, certainly as far as bittering goes, so it seems swings and roundabouts depending on which chilling method is used. That's another feature we could perhaps look at in the Calculator, would be a tough nut to crack though as there's even less info available about that effect?

As far as implementing bitterness in the Calculator goes, in the long run I feel you're doing it right and it would be unwise to assume there is nil impact on hops utilisation from Wort Bigness as per Tinseth et al, it is a given that eventually someone will be disappointed. I guess my own experiences aren't quite as helpful in this case though, perhaps just through the styles I brew. My greatest concern as far as hops goes has been inadequate late kettle hops character, however for bittering I can confidently say that seldom has it really presented as the big issue that some would have us believe.

Anyway, I'm looking forward to a new release- keep up the great work! :champ:

* Hmmm, I am starting to sound rather recalcitrant, but that's not the case! More like quite lazy, but also mindful of the forgiving nature of home brewing in general- even if I make precisely the same recipe by Maxi-BIAB that my friend makes conventionally, if my beer it isn't quite what my friend's is, the chances are still very good for them both to be delicious, just slightly different. I'm probably not so fussy as well, just glad to have some really decent beer!
[center]Give me a beer and I will move the world. Archimedes[/center]

Post #8 made 14 years ago
by ianh
stux wrote:The Tinseth formula has a part for "Wort Bigness" which takes care of scaling up the hop requirements as the gravity increases.

The probem is we don't know if this is correct in a concentrated scenario. But in theory, it should be.

The concern is what you have said about "However, IIRC I've never adjusted additions up on account of unexpectedly- low bittering"

BUT do you No Chill? No Chill could be compensating by perhaps increasing hop utilization by 30% ;)
hi Stux

I am also doing a BIAB spreadsheet and use the Tinseth formula. Whilst the formula takes in account the gravity, the problem I have is if you are doing a 90 minute boil and add hops at say 60 and 20 minutes how then do you account for the wort gravity. Do you calculate it at the 90 minute mark or the 60 and 20 minute marks or take the average for the time the hops are in the boil.

I get around the problem with possible increase in bitterness with NC by having the hops in hop bags and removing these at the end of the boil. I then sometimes dry hop into the NC cube or fermenter.

cheers

Ian
Last edited by ianh on 29 May 2011, 05:41, edited 6 times in total.

Post #9 made 14 years ago
by stux
Tinseth has said to use Average Gravity, which we take as the average of start and end of boil gravities

I did consider tilting this based on the average for the given addition, but gave up on that :)

One of the nice things with Maxi-BIAB is all the boil gravities tend to be very close as you often top up during the boil
Fermenting: -
Cubed: -
Stirplate: -
On Tap: NS Summer Ale III (WY1272), Landlord III (WY1469), Fighter's 70/- II (WY1272), Roast Porter (WY1028), Cider, Soda
Next: Munich Helles III

5/7/12

Post #10 made 14 years ago
by PistolPatch
Following your progress with enthusiasm stux :peace:

Have you managed to get the IBUs reading a bit higher so they are closer to the more mainstream programs as I haven't been able to boost it by much. It seems that at least one mainstream program uses volume into fermenter rather than end of boil volume. I still don't understand why they do this :scratch:.

Nice to see you playing with this too ian :salute:

Cheers
PP
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Post #11 made 14 years ago
by ianh
PistolPatch wrote: Nice to see you playing with this too ian :salute:

Cheers
PP
As I now do BIAB, I am modifying my Kits & Extract spreadsheet (as found on AHB) for BIAB and just trying to get my head round the differences. Will post when happy with it.

cheers
Ian
Last edited by ianh on 30 May 2011, 05:34, edited 6 times in total.

Post #12 made 14 years ago
by stux
PistolPatch wrote:Following your progress with enthusiasm stux :peace:

Have you managed to get the IBUs reading a bit higher so they are closer to the more mainstream programs as I haven't been able to boost it by much. It seems that at least one mainstream program uses volume into fermenter rather than end of boil volume. I still don't understand why they do this :scratch:.

Nice to see you playing with this too ian :salute:

Cheers
PP
I checked the numbers the calculator is generating against Glen's own Javascript calculator

http://www.realbeer.com/hops/bcalc_js.html" onclick="window.open(this.href);return false;

Using End-of-boil volume and Average OG for Boil, the numbers are the same.

The problem is glen's own page on the formula states

http://www.realbeer.com/hops/research.html" onclick="window.open(this.href);return false;

Code: Select all

mg/l of added alpha acids = decimal AA rating * grams hops * 1000
                            -------------------------------------
                              volume of finished beer in liters
Which is a concern.

Its quite possible that he originally derived his curve based on his final volume. ie he has accounted for HIS kettle trub in his formula. Which is madness.

If he had of done it based on kettle volume then the numbers would apply everywhere, but if he based it on his system, that includes trubs, then the numbers mean nothing, but are always relative to the same system.

Which is what he says, whenever he is asked.

Sigh.

So, I suspect that the real formula is "volume of finished beer in liters on Glen Tinseth's homebrew keggle system"

Which is why other programs take the "volume into the fermenter"

But the thing is "finished beer" implies packaged beer. And anyone can see that how you package the beer should not make a difference, but if you leave 50% of the wort behind in both the keggle and fermenter, then your hop matter required will be twice what it would've been without that waste, but this formula would not take that into account.

I think I'm going to shoot him an email.
Last edited by stux on 30 May 2011, 13:34, edited 6 times in total.
Fermenting: -
Cubed: -
Stirplate: -
On Tap: NS Summer Ale III (WY1272), Landlord III (WY1469), Fighter's 70/- II (WY1272), Roast Porter (WY1028), Cider, Soda
Next: Munich Helles III

5/7/12

Post #13 made 14 years ago
by stux
So, an IBU is essentially mg/L of AA

This is obviously relative to the the total Litres. So I would say, that the correct volume to use when working out the IBU from the grams of hops * AA %ge is the volume of the boil.

Of course, that doesn't mean other users of the formulas aren't using "finished beer" instead of "end of boil volume"

The idea is that the Alpha Acids are disolved into a solution, and that gives you the IBU, if you reduce the solution through evaporation the IBUs are assumed to stay behind. If you dilute, the IBUs are diluted.

Removing some of the solution does not change the IBU, and this is why IBUs are better than AAUs and HBUs

The other issue with the calculator is it doesn't account for different utilization between Pellets, Pellets in a Bag, Flowers and Plugs.

The Tinseth formula is optimized for "fresh whole cones loose in the boil"

So, we're not doing the fudging

"Al Korzonas suggests adding 10% more hops if used in a hop bag, and 10% more than that if loose hops or plugs are used"

http://www.realbeer.com/hops/FAQ.html

Now, BeerSmith
http://www.beersmith.com/Help/estimatin ... s_tech.htm

"
Leaf and Plug Hop Adjustments - The BeerSmith hop database uses pellet hops as the default since that is the type most used by homebrewers. Leaf and Plug hops generally have lower hop alpha utilization than pellet hops. The default adjustment is an 8% loss (-8%) for plug hops and a 10% loss (-10%) for whole leaf hops.
"

So, the Tinseth formulas assume whole loose hops. Which means The Calculator is too.

We can compensate in The Calculator by either noting strongly that we're referring to "loose flowers" or we can build in a compensation factor, to bring it back to loose pellets by assuming an addition 10% on the grammage, and perhaps make that a settable value?

It gets very complicated very quickly ;)
Fermenting: -
Cubed: -
Stirplate: -
On Tap: NS Summer Ale III (WY1272), Landlord III (WY1469), Fighter's 70/- II (WY1272), Roast Porter (WY1028), Cider, Soda
Next: Munich Helles III

5/7/12

Post #14 made 14 years ago
by stux
I just changed L11 (the IBU calcualtion) in my experimental hop bill to

Code: Select all

=IF(E11="",B11*1.1*((C11*100)*(((1.65*0.000125^($H$5-1))*((1-2.71828182845904^(-0.04*G11))/4.15))*100))/(10*$E$8)/100,E11)
and

I11 (the scaled grams)

Code: Select all

=(10*L11*$L$7)/(((((1.65*0.000125^($H$5-1))*((1-2.71828182845904^(-0.04*G11))/4.15))*100))*J11)/1.1
This has the effect of increasing the potency of the original hop weight by 10%, which increases the IBU contribution inline with assuming 10% extra addition form pellet hops, and then scaling the grammage back by 10% which compensates for the pellets on the reverse.

This means the same grams are calculated, but brings up the IBU contribution.
Last edited by stux on 30 May 2011, 14:03, edited 6 times in total.
Fermenting: -
Cubed: -
Stirplate: -
On Tap: NS Summer Ale III (WY1272), Landlord III (WY1469), Fighter's 70/- II (WY1272), Roast Porter (WY1028), Cider, Soda
Next: Munich Helles III

5/7/12

Post #15 made 14 years ago
by stux
While trying to get to the bottom of this, found this interesting post from some BIABrewer guy signing off as Pat

http://beersmith.com/beta/index.php?topic=155.0

;)

Which is exactly what I'm getting at.

Brad Smith replied that, yes, his IBUs are after post boil dilution etc into the fermenter.

The problem there is what's happened to the trub then?

So, perhaps Beer Smith is telling you the IBUs in the Fermenter... but is it calculating that based on Kettle IBUs, and then the final harvested volume diluted into the fermenter?

(I hope so ;))

Again, it comes down to what Glen meant by "finished beer", and I've found a few references, some insist its obviously the "end of boil volume"

I hope so, because everything else is a complete crap-shoot.

Anyway, in my maxi-hop calculations I've determined the IBUs assuming average boil gravity and the final ideal diluted volume, and I do believe that is an accurate way to calculate them.

The problem is if the original formula has kettle trub built in to the calculations!
Fermenting: -
Cubed: -
Stirplate: -
On Tap: NS Summer Ale III (WY1272), Landlord III (WY1469), Fighter's 70/- II (WY1272), Roast Porter (WY1028), Cider, Soda
Next: Munich Helles III

5/7/12

Post #16 made 14 years ago
by stux
I had a look at Beer Alchemy, which has the following preferences by default

"
IBU Adjustment for Bagged Hops: 0.9 x loose whole hops
IBU Adjustment for Loose Pellet Hops: 1.1 x loose whole hops
IBU Adjustment for Bagged Pellet Hops: 1.0 x loose whole hops
"

I wonder where Beer Alchemy is applying those adjustment factors...

And the other thing is Brad Smith basically answered my original question quite succinctly in the above thread

"The difference between the "into fermenter" volume and "end of boil" volume is in most cases dominated by any post-boil additions (such as with many extract brewers). The effect of adding water in this phase (i.e. diluting) is a simple dilution calculation for the IBUs. So if one starts with 3 gallons of wort with a given IBUs and adds two more gallons of water the net number of IBUs is still the original number scaled into the larger volume"
Last edited by stux on 30 May 2011, 15:10, edited 6 times in total.
Fermenting: -
Cubed: -
Stirplate: -
On Tap: NS Summer Ale III (WY1272), Landlord III (WY1469), Fighter's 70/- II (WY1272), Roast Porter (WY1028), Cider, Soda
Next: Munich Helles III

5/7/12

Post #17 made 14 years ago
by stux
And, here is a thread where someone call's out BeerSmith on using Pellets as a baseline instead of flowers when using tinseth.

http://www.beersmith.com/forum/index.php?topic=3451.0

Essentially, this means that BeerSmith is underestimating IBUs by about 10%?

Brad admits there may be a problem...

GuitarLord5000 seems to imply that he compensates by taken the calculated IBU and increasing by 10%. I think the way to increase it is to increase the utilization factor by 10%, which is also the same as simply increasing the hop matter by 10%

"
And Glenn's reply:
All of my experiments were carried out using whole hops. I never used pellets at all.

Various folks have come up with estimates for the use of pellets with my formula, but they have no basis in experimental results.

Glenn
"

Horse's Mouth.

And Brad's response

"
Thanks Dave,
If that is truly the case I will certainly look at modifying it on the next update.
"

...

So, from my investigations, places of variance with The Calculator and various other software

1) We are now using Average Gravity (which is correct)
2) We are using End of Boil Gravity (which I believe to be correct)
3) We are assuming Whole Hops (which is not necessarily what users are assuming, and BeerSmith is assuming Pellets)

1, as we have determined is already correct
2, I believe is correct, we just need to be explicit that we are talking End Of Boil IBU
3, Pellet Hops vs Whole Hops, if we want to add a Pellet/Whole hop conversion we need to provide the factors. I like the way Beer Alchemy does this with popup tabs.
Fermenting: -
Cubed: -
Stirplate: -
On Tap: NS Summer Ale III (WY1272), Landlord III (WY1469), Fighter's 70/- II (WY1272), Roast Porter (WY1028), Cider, Soda
Next: Munich Helles III

5/7/12

Post #18 made 14 years ago
by stux
I liked this reply ;)

http://homebrewingadventures.blogspot.c ... n-hop.html

At the end of the day, we need to produce an IBU number which gels with what the users expect, but also an IBU number which as best as possible allows us each to scale volumes and gravities to consistently reproduce our own recipes.
Fermenting: -
Cubed: -
Stirplate: -
On Tap: NS Summer Ale III (WY1272), Landlord III (WY1469), Fighter's 70/- II (WY1272), Roast Porter (WY1028), Cider, Soda
Next: Munich Helles III

5/7/12

Post #19 made 14 years ago
by stux
More observations on various softwares being out

http://www.aussiehomebrewer.com/forum/i ... opic=34381

ProTools & Tinseth use Flowers as Baseline
Beersmith and Beer Tools Pro use Pellets

(Remembering that "loose flowers" is the correct baseline according to Tinseth)

And a wave to ianh ;)
http://www.aussiehomebrewer.com/forum/i ... t&p=408105

Do you think its fair to say that the gravity part of Tinseth accounts for this? Well, that'd only be if the wort was concentrated, I think you were referring to the solution becoming saturated with hop AAs.

And butters nails it once more
http://www.aussiehomebrewer.com/forum/i ... opic=27384
Fermenting: -
Cubed: -
Stirplate: -
On Tap: NS Summer Ale III (WY1272), Landlord III (WY1469), Fighter's 70/- II (WY1272), Roast Porter (WY1028), Cider, Soda
Next: Munich Helles III

5/7/12

Post #20 made 14 years ago
by Pat
2.5 hours of writing stux! Glad to see someone else as baffled with this :scratch:. Great to see you making some real progress.

Will shoot you a PM now.

Will look forward to seeing what Ian comes up with as well.

:clap:
Pat
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Post #21 made 14 years ago
by ianh
Pat wrote:2.5 hours of writing stux! Glad to see someone else as baffled with this :scratch:. Great to see you making some real progress.

Will shoot you a PM now.

Will look forweard to seeing what Ian comes up with as well.

:clap:
Pat
Well as you can see we have a problem, for which there is probably no correct answer as we (without an analytical laboratory) cannot measure IBU's and there are so many posible variables even more for someone who NC's. If Tinseth, Rager and Garetz cannot agree what chance do we stand, although most agree Tinseth's is the best method of calculating IBU's.

My thoughts are to use hop pellets as standard (my spreadsheet will only include pellets as that's all I use) and as commonly used by homebrewers also I am thinking of using the average gravity between the time the hops are introduced and end of boil.

Not making allowances for hop bags as that just introduces another variable, is the hop bag a small affair that tightly bounds the hops or a very spaceous affair that allows the hops great freedom, could have different factors.

I think the program/software should produce a consistent best estimate of IBU, I certainly don't have the experience on tasting a beer to critically relate the IBU to the beer balance.

Interesting subject we could be here for weeks.
Last edited by ianh on 30 May 2011, 19:09, edited 6 times in total.

Post #22 made 14 years ago
by stux
I have added a "hop utilization factor" to my hop bill spreadsheet. By default it will be 1.1 which is suitable loose pellets

I'm the same, only using loose pellets :)
Fermenting: -
Cubed: -
Stirplate: -
On Tap: NS Summer Ale III (WY1272), Landlord III (WY1469), Fighter's 70/- II (WY1272), Roast Porter (WY1028), Cider, Soda
Next: Munich Helles III

5/7/12
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