Hop Stand Bittering Units - HSBUs

[LouieMacGoo]

As homebrewers we are always looking at ways to improve our beer and gain consistency in our processes and brewing methods. Over the last year or so, possible due to the popularity of New England IPAs (NEIPAs) it seems like the use of hop stands has become a more prevalent method of adding bitterness, flavor, and aroma to our beer. One of the problems with this method is being able constantly determining how much bitterness and flavor you are actually getting from the hop stand especially across multiple batches of beer.

On a recent episode of Basic Brewing Radio James Spencer introduced the Hop Stand Bittering Unit and I thought it was an interesting concept that might actually be useful


Read the full article here then come back and let us know what you think.

[BlackDuck]

Couple things I noticed right away. Someone needs to go back to basic math class!!! (Damn, I hope it's not you Louie!!!)
First, the calculation for the metric example of the cascade hops is incorrect:
Metric: 28 g X 7 AA = 28 |28 divided by 18.9 liters of wort = 1.48 HSBUs. It should be 28 g x 7 AA = 196 (not 28) so 196 divided by 18.9 liters of wort = 10.37 HSBUs

Second, the calculation for the english example of the citra hops is also incorrect, but not by much:
English: 2 oz X 17.5 AA = 35 | 35 divided by 5 gallons of wort = 6 HSBUs. It should be 2 oz X 17.5 AA = 35 | 35 divided by 5 gallons of wort = 7 HSBUs, not 6 HSBUs

Third, he mentions that temperature is important in determining your baseline, but temperature isn't used in the formula at all. So does it matter or not??? This same argument applies to the length of time of the hopstand. Time is also not included in the formula.

Finally, for the real head scratcher...So what this guy is telling me is that if I switch my measuring unit from english to metric, I'll get an exponentially higher amount of HSBUs. In the Citra example, I would go from 7 HSBUs to 51.9 HSBUs when I'm really using the same exact amounts of everything, just measured in different units????? 2 ounces = 56 grams and 5 gallons = 18.9 liters, so everything is basically the same, except the final answer!!!! I wonder if the IBU equation works the same way, I'll start making IPA's with mind boggling IBU numbers. All I need to do is start measuring in metric units.

SO...in the end, for me...this is a bit overboard for a homebrewer. And I also think it's probably incorrect since temperature and time are not used in the equation.

[LouieMacGoo]

Couple things I noticed right away. Someone needs to go back to basic math class!!! (Damn, I hope it's not you Louie!!!)
First, the calculation for the metric example of the cascade hops is incorrect:
Metric: 28 g X 7 AA = 28 |28 divided by 18.9 liters of wort = 1.48 HSBUs. It should be 28 g x 7 AA = 196 (not 28) so 196 divided by 18.9 liters of wort = 10.37 HSBUs

Second, the calculation for the english example of the citra hops is also incorrect, but not by much:
English: 2 oz X 17.5 AA = 35 | 35 divided by 5 gallons of wort = 6 HSBUs. It should be 2 oz X 17.5 AA = 35 | 35 divided by 5 gallons of wort = 7 HSBUs, not 6 HSBUs

Third, he mentions that temperature is important in determining your baseline, but temperature isn't used in the formula at all. So does it matter or not??? This same argument applies to the length of time of the hopstand. Time is also not included in the formula.

Finally, for the real head scratcher...So what this guy is telling me is that if I switch my measuring unit from english to metric, I'll get an exponentially higher amount of HSBUs. In the Citra example, I would go from 7 HSBUs to 51.9 HSBUs when I'm really using the same exact amounts of everything, just measured in different units????? 2 ounces = 56 grams and 5 gallons = 18.9 liters, so everything is basically the same, except the final answer!!!! I wonder if the IBU equation works the same way, I'll start making IPA's with mind boggling IBU numbers. All I need to do is start measuring in metric units.

SO...in the end, for me...this is a bit overboard for a homebrewer. And I also think it's probably incorrect since temperature and time are not used in the equation.

Chris, first off thanks for the math check I was tired when I was putting this together is that totally slipped by.

Second, for the temp and duration it's important that if you do a hop stand at 190*F for 30 minutes that you use that same temp and duration across all your brewing so that the numbers are consistent. So it is important but as a separate consideration.

Third, if you listen to the podcast it makes more sense. This isn't a hard and fast number it just a formula for trying to make sure the bitterness that your trying to achieve from doing the hop stands is consistent across your brewing. In the podcast he mentions that it's not like IBUs that can be scientifically measured. HSBUs is simply a formula for helping you establish a baseline in your own brewing.

Thanks for your feed back.

[BlackDuck]

I will admit that I didn't listen the podcast, just read what was posted. I see what you're saying about it not being a hard and fast number and that it's just getting a ballpark. That's why I think it's overboard for a homebrewer. There just seems to be too many variables. In my mind, if you're going to put a number on something, that number needs to mean something. And it needs to be consistent across the board. What I mean by that is you and I could get the same number, but it would mean something totally different if my hopstand was 45 minutes and yours was 15 minutes, and we brewed the same recipe with the same volumes. The number would say we got the same HSBUs when we really didn't.

[Beer-lord]

I probably have listened to all James' podcasts for the last 6 years or so. Only recently do I remember him discussing this. He's been pretty adamant about this being just a quick and dirty way to figure out your IBU's and it's definitely not scientific.
They keep things pretty real in their podcasts and just have fun. It looks like he's got a good gig!

[mashani]

The AAU extraction works somewhat exponentially with temperature. But it is also affected by time and ph. Because as I've said before time, temperature, and ph all affect such reactions. So an exact formula becomes very complex.

But there is a simple way to think of it which is close enough for most things which is:

Somewhere in the range of 150-160 = ~5% AAUs vs. boiling for same time.
Somewhere in the range of 160-170 = ~10% vs. boiling for same time.
Somewhere in the range of 170-180 = ~20% vs. boiling for same time.
Somewhere in the range of 180-190 = ~40% vs. boiling for same time.
Somewhere in the range of 190-200 = ~80% vs. boiling for the same time.

Those are of course by no means exact, hence the ~(about), but based on experience they will give you the results expected perception wise or be close enough that you will be alright with the results. The no-boil beers where I never exceeded 150 (actually 152 or 153 because mash & boil on/off cycle) and I used hops to achieve around 21 IBUs and 50ish IBUs based on that ~5% estimate had perceptually the right amount of bitterness in both cases, and the bitterness was stable over time. (admittedly only 4 months of time because those beers got consumed quickly, they were good!)

Also remember perception wise most people can't really detect an IBU difference unless it's ~7 or so, and in the case of nutty IPAs, once it gets above a certain # it matters not at all, it's just as bitter as it's gonna taste. (IE anywhere above 100 most people aren't going to tell anymore, it's just more bitter in a theoretical sense, not necessarily perceptual).

Lab tests will of course show a higher variability then those simple numbers above, but if you can't perceptually taste the difference why does it matter? Those simple #'s get you in the ballpark, and then you can tweak next time you brew based on how you perceive the ballpark to make it perfect for you. I say you because everyone's perceptions are different.

Really the AAUs in your hops are quite possibly not what it says on the label as we have also discussed before, because you can't control storage conditions from origin to your freezer and different hops degrade at different rates over time/temperature ranges, some quite rapidly, others not so much. So without a lab at hand, all we are really doing is tossing around miniature hand grenades and calling it close enough anyways when it comes to this sort of thing.