Hop Utilization - Is there a minimum boil volume?!

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RoaringBrewer

RoaringBrewer

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So, let's say I want to brew an IPA soon, but its too cold to brew on the bayou burner/turkey frier, thus I'm restricted to a kitchen range (glass, electric top). I have trouble boiling 1.5g on this thing sometime...

My question is this. With a full boil, I may be able to draft up a good IPA using 4-6oz. of hops total (1-2oz. high alpha bittering, 1-2oz. flavor/flameout, 1-2oz. dryhop).

However, with a 1.0 - 1.5g boil and the (majorly) decreased utilization, this will drive my need for hops up to probably 10oz. or so. Obviously this makes brewing the IPA more expensive, but if I don't mind the increased cost of hops, is it possible to do an IPA with such a small boil?!

I'm wondering if there is a point where normal hop utilization theory goes out the window and you just can't get anymore hop bitterness into the water with such a small boil. If I can do an IPA with 1.0-1.5g boil, I know I'll basically need to double (or triple) the bittering and flavor hops to get the required IBU (I have beersmith so conversion is easy), but is it even possible?
 
The maximum IBU load works out to 90 IBU @ 212F. (none of the calculators I've seen observe this limit) So, if you boil a gallon of water with your hops & dilute to 5 gallons, you'll have 18 IBU. If you have a pressure cooker, you can kick this to 130 IBU.
 
I'm not sure I follow your explanation exactly; are you saying that the maximum IBU I can attain by doing a partial boil of 1g would be 18IBU?!

This just doesn't seem right to me (unless I'm misunderstanding the response). That would limit the recipes a partial boiler could do to 'light' beers and hefeweizens for the most part...

Or it could be right and I am in definite need of doing full boils... I usually boil 1.5g (but this would put my max IBU for any recipe) around 27...

EDIT: Beersmith doesn't even account for this 'limit'. I can plug in endless 1.5g recipes and can get any IBU I want with enough hops. Why are the brew software people not accounting for this max?
 
Are you saying that boil temp has an impact on utilization? At 9000' my water boils at about 195. Does that mean my utilization is significantly lower? If so, is there a calculator (or better a formula) that factors in boil temp?
 
I wish I could find the page that I saw that explained the effects of temperature but the short answer is yes, it definitely affects the utilization but I think you can compensate over a longer boil (or more hops).
 
Okay, the temperature question is another valid question; but what is the max IBU I can attain if doing 1.0 or 1.5g boils? I'm quite worried (for all partial boilers) if we cannot conquer the 18-27IBU level due to boil volume alone...

Or can I still compensate for boil volume by adding additional hops?! For example, I would use 2.0oz. Chinook to bitter a 1.5g boil, as opposed to .55oz of the same hop for a full boil 5g boil in a recipe.

EDIT: For example, my very direct question is this. When I use beersmith to translate walker-sans IPA from a full boil to a 1.5g partial boil, it tells me I need 13oz of hops to hit 45 IBU. Is this correct or is their calculator not taking into effect some sort of maximum level of utilization? Even if it takes 13oz. of hops to make an IPA with a 1.5g boil, I'd be willing to do that at this point. But if I'm goin to toss in 13oz. of hops and only get a maximum of 27IBU, then I am not wasting the time or money on the hops. Follow?
 
SilkkyBrew said:
So, let's say I want to brew an IPA soon, but its too cold to brew on the bayou burner/turkey frier, thus I'm restricted to a kitchen range (glass, electric top).
Click to expand...

I brewed outside on Sunday*. :D

*In my car port
 
^ It's getting to the point (40ish) where I may be able to suck it up soon; this issue just sparker my curiosity in any case. Seems like there would be some point of no returns once you go too low on the boil volume (i.e. there is so high of gravity with 6lb. DME in 1.5g water there is no extra room for bittering acids to dissolve into the water...)

Anyone?
 
SilkkyBrew said:
^ It's getting to the point (40ish) where I may be able to suck it up soon; this issue just sparker my curiosity in any case. Seems like there would be some point of no returns once you go too low on the boil volume (i.e. there is so high of gravity with 6lb. DME in 1.5g water there is no extra room for bittering acids to dissolve into the water...)

Anyone?
Click to expand...

Have you seen this? I didn't read enough of it to see if it addresses your question directly, but it looked promising.
 
17F-13

Isomerization kinetics of hop bitter acids during wort boiling

M. G. MALOWICKI and T. H. Shellhammer. Dept. of Food Science & Technology, Oregon State Univ., 100 Wiegand Hall, Corvallis, OR 97331-6602

While overall hop utilization has been well defined functionally, there is a pronounced lack of published research pertaining to the actual kinetics of both the extraction of alpha acids from hops and their subsequent isomerization.

The rate of isomerization of alpha acids to iso-alpha acids (the bittering compounds in beer) was characterized over a representative pH and temperature range to model reaction kinetics during the boiling portion of the brewing process.

Solubility limits for alpha acids in a pH buffered solution were determined spectrophotometrically at 328nm. The conversion of alpha acids to iso-alpha acids was characterized in a model, laboratory scale system consisting of purified alpha acid extract in a pH buffered aqueous solution. Boiling occurred in multiple 12mL stainless steel vessels submerged in a temperature controlled mineral oil bath. Concentrations of humulones and iso-humulones were quantified at discrete points across a 90 minute boil using a standard HPLC analysis.

Maximum solubility of alpha acids in a pH 5.2 buffered aqueous solution was 90ppm. Hop isomerization kinetics examined over a broad range of temperatures showed a rate coefficient of 0.0153(1/sec) for atmospheric boiling conditions. At 70deg C, less than 10% of alpha acids were converted in a 90 minute boil. At 120deg C, only 30 minutes were required for 90% conversion, with subsequent loss of iso-alphas to degradation products following. Activation energy was determined to be 36.375 kJ per mole.

Precise understanding of isomerization kinetics allows improved accuracy in hopping rate calculation to achieve target concentrations of bitter compounds in wort, despite varying temperatures as the kettle approaches boiling, or as wort encounters a lag time prior to entering a heat exchanger for cooling. Also, understanding of kinetics is essential if novel regimes (short duration, high temperature, pressurized boiling) are to be explored for potential energy savings.

Session 17F, Food Engineering: Kinetics and mass transfer
8:30 AM - 12:00 PM, Tuesday AM Room Hall N-1

2004 IFT Annual Meeting, July 12-16 - Las Vegas, NV
 
david,

thanks for the article; however all this science is making my headspin. I am in need simple english explanations here; haha.

Anyway, it appears 90 is the max that can be dissolved into a liquid. So, if i hit the 90 max in 1 gallon, then dilute, I'm down to 18IBU. This is correct? (Good to know I won't be doing many partial boils anymore if this is the case!!)

My only question then is this. If the maximum ibu for a boil would be 90 (and for some reason you mentioned 130 with a pressure cooker? - assuming this was for a 7 gallon boil into a 5 gallon batch?), then how does one attain a 281IBU concoction as in your signature? It seems this would be impossible, no?

Sorry for being a pain; I'm just getting lost in the science of this when I really just want an explanation such as, "You can (or can't) brew a 45IBU recipe with only a 1.5 gallon boil." And I think a simple answer as this would benefit much of this board as there are many partial boilers here who are probably hopping to hell and back to attain 50-70IBU recipes from a partial boil and being dissappointed when it doesnt seem to happen...
 
david_42 said:
17F-13

Isomerization kinetics of hop bitter acids during wort boiling

M. G. MALOWICKI and T. H. Shellhammer. Dept. of Food Science & Technology, Oregon State Univ., 100 Wiegand Hall, Corvallis, OR 97331-6602

While overall hop utilization has been well defined functionally, there is a pronounced lack of published research pertaining to the actual kinetics of both the extraction of alpha acids from hops and their subsequent isomerization.

The rate of isomerization of alpha acids to iso-alpha acids (the bittering compounds in beer) was characterized over a representative pH and temperature range to model reaction kinetics during the boiling portion of the brewing process.

Solubility limits for alpha acids in a pH buffered solution were determined spectrophotometrically at 328nm. The conversion of alpha acids to iso-alpha acids was characterized in a model, laboratory scale system consisting of purified alpha acid extract in a pH buffered aqueous solution. Boiling occurred in multiple 12mL stainless steel vessels submerged in a temperature controlled mineral oil bath. Concentrations of humulones and iso-humulones were quantified at discrete points across a 90 minute boil using a standard HPLC analysis.

Maximum solubility of alpha acids in a pH 5.2 buffered aqueous solution was 90ppm. Hop isomerization kinetics examined over a broad range of temperatures showed a rate coefficient of 0.0153(1/sec) for atmospheric boiling conditions. At 70deg C, less than 10% of alpha acids were converted in a 90 minute boil. At 120deg C, only 30 minutes were required for 90% conversion, with subsequent loss of iso-alphas to degradation products following. Activation energy was determined to be 36.375 kJ per mole.

Precise understanding of isomerization kinetics allows improved accuracy in hopping rate calculation to achieve target concentrations of bitter compounds in wort, despite varying temperatures as the kettle approaches boiling, or as wort encounters a lag time prior to entering a heat exchanger for cooling. Also, understanding of kinetics is essential if novel regimes (short duration, high temperature, pressurized boiling) are to be explored for potential energy savings.

Session 17F, Food Engineering: Kinetics and mass transfer
8:30 AM - 12:00 PM, Tuesday AM Room Hall N-1

2004 IFT Annual Meeting, July 12-16 - Las Vegas, NV
Click to expand...


please put this into plain english ibu/gal
 
SilkkyBrew said:
david,

thanks for the article; however all this science is making my headspin. I am in need simple english explanations here; haha.

Anyway, it appears 90 is the max that can be dissolved into a liquid. So, if i hit the 90 max in 1 gallon, then dilute, I'm down to 18IBU. This is correct? (Good to know I won't be doing many partial boils anymore if this is the case!!)

My only question then is this. If the maximum ibu for a boil would be 90 (and for some reason you mentioned 130 with a pressure cooker? - assuming this was for a 7 gallon boil into a 5 gallon batch?), then how does one attain a 281IBU concoction as in your signature? It seems this would be impossible, no?

Sorry for being a pain; I'm just getting lost in the science of this when I really just want an explanation such as, "You can (or can't) brew a 45IBU recipe with only a 1.5 gallon boil." And I think a simple answer as this would benefit much of this board as there are many partial boilers here who are probably hopping to hell and back to attain 50-70IBU recipes from a partial boil and being dissappointed when it doesnt seem to happen...
Click to expand...

Can you do a 2.5 or 3 gallon partial boil?
 
Hold on a second. "Maximum solubility of alpha acids in a pH 5.2 buffered aqueous solution was 90ppm." Since when is IBU measured in alpha acid ppm? I think we're overlooking something.
 
I'm guessing I'd never (read 1-2 hours just to get to boil with lid on) get 2 gal + to a boil on this range. It takes about 30-45 mins to get 1.5g to a boil...

If I could do a 3g boil, then my point would be moot b/c I could brew (if I understand david's explanation) 54IBU brews with a 3 gallon boil. Won't happen though until I can brew outside on the turkey frier.

In any case, I think this is a common misconception (if, again, I understand david's theory) here that with enough hops or a long enough boil you can hit any IBU desired in as small a boil as you desire. Just seems unreal that all these 1.5gallon boil kits you can buy from austinhomebrew, midwestsupplies, etc. would have a max IBU of 27... I dont know...
 
Bobby_M said:
Hold on a second. "Maximum solubility of alpha acids in a pH 5.2 buffered aqueous solution was 90ppm." Since when is IBU measured in alpha acid ppm? I think we're overlooking something.
Click to expand...

This is why I would like a layman's terms explanation...
 
I found this also:


"Mitch Steele-an assistant brew master at Anheuser-Busch who also judged the category-provides an English translation:

"The maximum IBU level in a beer is somewhat dependent on composition of the beer. A higher alcohol, higher gravity beer can have more IBU than a beer at 5 percent alcohol. A 5 percent beer will max out at 120 parts per million iso-alpha acids, which corresponds to about 80 IBU. It is physically impossible to have more IBU than that in a 5 percent beer. As alcohol and unfermented carbohydrate in the beer increases, so does the ability of the beer to carry more IBU. Our hop research expert feels that the claim that some barley wines have over 100 IBU is probably valid."

This is from http://www.allaboutbeer.com/features/246doubleIPA.html
 
Is it a gas or electric range? My electric range will bring 3 gallons to a boil in under an hour. Perhaps not all ranges are capable of that, but it seems like even two gallons would help a lot here (although still not enough for an IPA). You could go the ugly route and use another pot to make some "hop tea" and add that to your wort.

This is why I always hated chemistry. :drunk:
 
Bobby_M said:
I found this also:


"Mitch Steele-an assistant brew master at Anheuser-Busch who also judged the category-provides an English translation:

"The maximum IBU level in a beer is somewhat dependent on composition of the beer. A higher alcohol, higher gravity beer can have more IBU than a beer at 5 percent alcohol. A 5 percent beer will max out at 120 parts per million iso-alpha acids, which corresponds to about 80 IBU. It is physically impossible to have more IBU than that in a 5 percent beer. As alcohol and unfermented carbohydrate in the beer increases, so does the ability of the beer to carry more IBU. Our hop research expert feels that the claim that some barley wines have over 100 IBU is probably valid."

This is from http://www.allaboutbeer.com/features/246doubleIPA.html
Click to expand...

Okay, so this is helping somewhat. A 5% beer will max out around 80-90IBU (consistent with david's assertion). So, even if you full boil it, you can't claim your 7% IPA has 250IBU. And it would appear the max IBU you could get into a 1.5g boil would be 90, which would dilute to 27 after bringing to 5g in the fermenter... Hrm... I guess I could do a 1.5g boil and dilute to only 3 gallons. This would provide me the 45IBU I'm aiming for (90 diluted by 1/2)...

ayrton - its an electric range with glass top (the kind where the burner is recessed under glass) and it sucks. it takes 25 minutes to preheat to 400 to cook a pizza and the stovetop isn't much better at boiling things.

EDIT: I've adjusted my recipe slightly and if I brew a 1.5g boil and dilute to only 3g, beersmith tells me I'll see 55IBU. Oviously this would be against the assertion made by david (90IBU max in boil, dilute in half would see 45IBU max), so i think this is what I'll do and hope I get around 45IBU (as that was the original intention - to just barely break into IPA land).
 
The hopwine in my sig. shows how ridiculous one can be. In reality, it isn't any more bitter than something like Hop Rod Rye.

If you are limited in your boil size, the simple thing to do is prepare a couple gallons of pre-bittered cooling water the night before. A half ounce of 12% Chinook in 1.5 gallons for 30 minutes will hit 90 IBU.
 
david_42 said:
The hopwine in my sig. shows how ridiculous one can be. In reality, it isn't any more bitter than something like Hop Rod Rye.

If you are limited in your boil size, the simple thing to do is prepare a couple gallons of pre-bittered cooling water the night before. A half ounce of 12% Chinook in 1.5 gallons for 30 minutes will hit 90 IBU.
Click to expand...

Hrm... Never really thought about the hop-tea in cooling water idea. This may be the way to go if I want to make the recipe to 5g. with a 1.5g boil.

Thanks david!
 
So, I think this is what I'll be doing in order to get a 5g batch. Let me know if this sounds correct?

Boil 1.5g with 1/2oz. Chinook (which was my main bittering hop by chance) for 30 minutes the night before and chill as cooling water. Per Beersmith this will give me 85IBU with my 12.4%AA Chinook and plain water. 85IBU when diluted to 5 gallons would be 17IBU per gallon of the final product. So, I'd get 17IBU * 1.5g out of this hoptea in the final product (or 25.5IBU).

Perform the normal 1.5g boil with the remainder of the bittering, flavor, and finishing hops. The hops that will be going into this boil will most definitely max it out at 90IBU (1.5oz. chinook and a couple ounces northern brewer/cascade), so when that 90IBU is diluted to 5 gallons, I'll get (90/5*1.5g boil) 27IBU out of that boil.

Combine the 2 (3g total hopped) and I should be around 52.5IBU after diluted with 2 gallons of normal cooling water? (This seems in line assuming if I did a 3g boil and diluted it to 5, I'd be around 54 if the boil was maxed out at 90IBU)
 
david,

do you see any problem with also steeping my steeping grains at the same time as the hop-tea boil? I don't believe the steeping of crystal will add any (significant) gravity to the water. This may save me another 30 mins on brew day if I do it the night before? Or will the steeped grain runnings not dilute into the beer when the extract/hop boil is added (i.e. do i need to boil the liquid from steeping grains for an hour with the extract or can i steep grains, then boil hop tea and put in fermenter to cool until the next day when I'll add the rest of the wort).
 
Well I brewed this up. Some of it is still in the secondary (on day 11, dry hopping on 1oz cascade), however when I racked to secondary I wanted to keep as much trub out as possible, so I left about 2 bottles of beer on the cake.

I then carefully siphoned this off and bottled it to get SOME idea of what it may be like when finished. This is carbed up after 11 days and I can't say I'm impressed. Very light mouthfeel (maybe not so bad if the rest was good), but lacking the hop flavor/aroma (obviously I didn't dry hop these two bottles I bottled) I had envisioned. Definitely NOT lacking the bitterness. At the back of the pallette there is a very strong hop bitterness bordering on astringency (but its not off-flavor astringency). The rest of the hop profile seems to be absent though. What happened to the 7 additions between 1 and 30 minutes I did?! Will these show up over time?! Will the drop hop bring this out?! I definitely hope so because this isn't something I desire to drink two cases of.

It's smooth and light in a way, but the bitterness bite at the end seems a little over the top for only 55 IBU. Further, it has no hop complexity in the mid-palate. What happened? Will this age better? Will the drop hop help that much? I sure hope so!
 
BUMP!

Sorry to bring this topic back from the dead, RoaringBrewer, but this problem is something that *many* new brewers experience. Would you mind explaining what went wrong, or how the batch turned out later?

Thanks!
 
david_42 said:
17F-13

Isomerization kinetics of hop bitter acids during wort boiling

M. G. MALOWICKI and T. H. Shellhammer. Dept. of Food Science & Technology, Oregon State Univ., 100 Wiegand Hall, Corvallis, OR 97331-6602

While overall hop utilization has been well defined functionally, there is a pronounced lack of published research pertaining to the actual kinetics of both the extraction of alpha acids from hops and their subsequent isomerization.

The rate of isomerization of alpha acids to iso-alpha acids (the bittering compounds in beer) was characterized over a representative pH and temperature range to model reaction kinetics during the boiling portion of the brewing process.

Solubility limits for alpha acids in a pH buffered solution were determined spectrophotometrically at 328nm. The conversion of alpha acids to iso-alpha acids was characterized in a model, laboratory scale system consisting of purified alpha acid extract in a pH buffered aqueous solution. Boiling occurred in multiple 12mL stainless steel vessels submerged in a temperature controlled mineral oil bath. Concentrations of humulones and iso-humulones were quantified at discrete points across a 90 minute boil using a standard HPLC analysis.

Maximum solubility of alpha acids in a pH 5.2 buffered aqueous solution was 90ppm. Hop isomerization kinetics examined over a broad range of temperatures showed a rate coefficient of 0.0153(1/sec) for atmospheric boiling conditions. At 70deg C, less than 10% of alpha acids were converted in a 90 minute boil. At 120deg C, only 30 minutes were required for 90% conversion, with subsequent loss of iso-alphas to degradation products following. Activation energy was determined to be 36.375 kJ per mole.

Precise understanding of isomerization kinetics allows improved accuracy in hopping rate calculation to achieve target concentrations of bitter compounds in wort, despite varying temperatures as the kettle approaches boiling, or as wort encounters a lag time prior to entering a heat exchanger for cooling. Also, understanding of kinetics is essential if novel regimes (short duration, high temperature, pressurized boiling) are to be explored for potential energy savings.

Session 17F, Food Engineering: Kinetics and mass transfer
8:30 AM - 12:00 PM, Tuesday AM Room Hall N-1

2004 IFT Annual Meeting, July 12-16 - Las Vegas, NV
Click to expand...


To anyone still reeling from the numbers of this, it has nothing to do with boil volume. This is finding a relationship between temperature and conversion of alpha acids to iso-alpha acids. Iso-alpha acids create the bitterness, not alpha acids. Boiling wort both extracts the alpha acids from the hops and converts them to iso-alpha acids. Note that without the use of a pressure cooker, you cannot obtain a temperature above 100C, nor would you (I hope) attempt to make wort at 70C. Based on this study, it's easy to see why we tend to boil for 60 mins at 100C (90 mins at 70C gave 10% conversion, 30 mins at 120C gave 90% conversion). This study would be extremely useful if you were thinking about trying a pressure cooker and still getting the same hop utilization with less time/energy. There's really only one key paragraph in there, the rest is methodology/conclusion so other scientists can replicate the study to confirm results. Unfortunately, that tends to make the study extremely dense for non-scientists.

Please note that I am new to brewing, but I am a chemist. As such, some of my understanding regarding making beer might be a little off, but the run-down of the science in that study should be accurate.
 
RoaringBrewer said:
So, let's say I want to brew an IPA soon, but its too cold to brew on the bayou burner/turkey frier, thus I'm restricted to a kitchen range (glass, electric top). I have trouble boiling 1.5g on this thing sometime...

My question is this. With a full boil, I may be able to draft up a good IPA using 4-6oz. of hops total (1-2oz. high alpha bittering, 1-2oz. flavor/flameout, 1-2oz. dryhop).

However, with a 1.0 - 1.5g boil and the (majorly) decreased utilization, this will drive my need for hops up to probably 10oz. or so. Obviously this makes brewing the IPA more expensive, but if I don't mind the increased cost of hops, is it possible to do an IPA with such a small boil?!

I'm wondering if there is a point where normal hop utilization theory goes out the window and you just can't get anymore hop bitterness into the water with such a small boil. If I can do an IPA with 1.0-1.5g boil, I know I'll basically need to double (or triple) the bittering and flavor hops to get the required IBU (I have beersmith so conversion is easy), but is it even possible?
Click to expand...

I disagree with many comments about full boils versus small boils and hop utilization. Hop utilization is really a factor of the worts density, which is relative to malt to water ratio.

Checking Papazian's TCJOHB Hop Utilization Chart recommends 1 gal of water and 1 lb of DME equalling approximately 1.040. BYO uses 1.045.

Keeping along those lines, if you boil 2 gals of water and use 2 lbs of DME is the same. Most of the time I use 1.5-2 gals for my boils and use as little as 3% AA for a bacth of sweet-side Hefe Weizen...more for pale ales etc., but I'm not really a hop head.
 
Papazian's chart does predict ballpark hop utilization based on wort density, but not entirely for the right reason according to new research http://media.libsyn.com/media/basicbrewing/bbr03-20-08ibu.mp3.

What actually affects hop compounds making it into the final beer is the amount of surface area exposed to the hop compounds during the boil. The break material in the boil, similar to the pores in activated charcoal, "mop up" quite a large percentage of the iso alphas; the walls of the kettle as well. Because higher gravity worts tend to have more break, they affect hop utilization more negatively. Extract beers, already having much of the break removed during processing (there's still quite a bit of course), tend to get better utilization because of this.

My suggestion would be to add a small amount of extract (~.25lb) to the small boil volume, add your hops taking into account the low boil volume (and low gravity..which should even things out a bit), and do a late extract addition the last 15mins, topping-up with water in the fermenter. The late-extract addition should minimize break formation.
 

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