Author Topic: HOPS! IBU and Use Profiles  (Read 186 times)

Offline naDinMN

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HOPS! IBU and Use Profiles
« on: May 01, 2021, 12:39:50 PM »
So, I have two questions really.

1. When I enter a recipe I find online, my IBUs never match up. I account for AA%. I've tried all three profiles. But if I'm supposed to get 20 IBUs according to the recipe, I get 50 in BeerSmith. What's up?

2. Is there a way to add a new use profile for hops? I'm experimenting with dip hopping and I want to keep track within the software. I'd prefer not to use notes, but if that is all I can.

Thanks!

Offline Oginme

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Re: HOPS! IBU and Use Profiles
« Reply #1 on: May 01, 2021, 02:31:44 PM »
IBU calculations can be very fussy.  First, there are several models being used and you don't always know which one the person printing the recipe is using if it is not expressly stated. 

Next, the bitterness you perceive in your beer is unique to your process: boil vigor, surface area of your kettle, boil off rate, wort pH, and water chemistry.  There is no way of determining how the recipe you are following matches up with your process and results unless you are trying to clone a commercial beer and taste testing against it -- which by the way is a great way to help you understand how your process may match up with a commercial beer which may (or may not) actually be tested for IBU.

Third, IBU is really a poor indicator of beer bitterness.  The test method was designed for mostly single hopped beers with low bitterness and is only significant for isomerized alpha acids (ignoring other compounds which might also absorb at the same wavelengths).  Some of the current models do account for shorter hop boil times, but even then the measurement is using the test method which is not designed for correlation to perceived bitterness of these hop schedules.  The method also ignores bitterness contributions from oxidized alpha acids and beta acids for the hops.

Specific to your differential, without seeing your recipe, process and the original recipe as a comparison, it would be pure speculation to give any meaningful advice.

As to your second question, I would add hop dipping as a form of dry hopping with basically no days of contact.  Since this dry hop additions do not contribute to IBU calculations and this method is closer to a form of dry hop (though with obvious handling and contact time differences) it would seem to be the best way of tracking this method right now.  You can always add a request in the suggestions forum for Brad to include the option of listing a hop addition as a dip hop. 
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Offline naDinMN

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Re: HOPS! IBU and Use Profiles
« Reply #2 on: May 12, 2021, 09:38:39 AM »
Thank for the reply.

Offline BOB357

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Re: HOPS! IBU and Use Profiles
« Reply #3 on: May 12, 2021, 12:49:39 PM »
Just to add to what Oginme stated, differences in process and/or system can have an affect on IBUs, as well as other characteristics. You can't expect to brew the same beer as the author of the recipe. It just doesn't happen.

 Another thing to consider is whether the recipes you're finding on line are reasonable or posted by total idiots. Plenty of them going around. Hopefully you're not trusting that the recipes are legit. Just because you find a recipe on BeerSmith, Brewers Friend, or other trusted site doesn't make it a good recipe. Nobody evaluates them. By the time you learn to discern between the two, you'll be able to put together your own.

Bob

Offline naDinMN

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Re: HOPS! IBU and Use Profiles
« Reply #4 on: May 13, 2021, 11:12:34 AM »
Yeah, I've been brewing my own recipes for 14 years, which is probably why I never noticed it before.

The recipes I'm referring to, one in.particular really, are from professional brewers who've supplied their recipes to BYO.

Offline BOB357

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Re: HOPS! IBU and Use Profiles
« Reply #5 on: May 13, 2021, 12:48:45 PM »
Pro brewers make mistakes too, and then there are typos that make it past the editors. Maybe that's the case in the recipe that stands out. Also, IBUs don't scale well, especially between large pro systems and homebrew size batches. In the rare cases that I use someone else's recipe, I just make my hop additions equal their IBUs. If the recipe seems unreasonable, I don't brew it.
Bob