Different IBU's provided by different software?

Moody_Copperpot · 01-15-2011, 03:46 PM

I just signed up for the trial of beersmith and I'm noticing that the IBU's provided by Beersmith, Hopville, and spreadsheet made by an HBT member that I use as well, are all different. I don't have the spreadsheet info, but beersmith is giving the recipe below 60.3 IBU and Hopville has it at 69.4.
The boil volume is about 7.5 gallons. I'll yield 6 and actually keg 5-5.5 after all is said and done with trub etc. What do you guys think about the IBU situation, I mean those are very different numbers. I have the hops set to pellets on each recipe builder, and I manually inputted the AA so that is the same as well, just the numbers are way off

LB OZ
73% 10 0 American Two-row Pale
7% 1 0 Maris Otter Two Row
7% 1 0 Victory Malt
5% 0 11 Cara-Pils/Dextrine
4% 0 8 Caramel/Crystal Malt - 40L
4% 0 8 Belgian CaraMunich

boil 45 mins 0.5 Warrior pellet 17.1
boil 30 mins 0.5 Warrior pellet 17.1
boil 20 mins 0.5 Columbus pellet 14.4
boil 10 mins 1.0 Cascade pellet 5.0
boil 5 mins 1.0 Cascade pellet 5.0
Flame Out 0.5 Columbus pellet 14.4

**Edcculus** · 01-15-2011, 03:53 PM

The software shouldn't give different numbers. You just need to make sure they are using the same formula. In beersmith, you can pick between Tinseth and Rager. Tinseth is a little more accurate, but if you use a lot of Jamil's recipes, your numbers won't match since he uses Rager in the podcasts and Brewing Classic Styles. Not sure which formula Hopville uses though. Since its web based, I don't think you can change it.

**Revvy** · 01-15-2011, 04:05 PM

Yup. it all depends on which default scale the software uses. There's plenty of threads on here discussing it. Somewhere it should tell you what the default setting is, and even give you the option to change it. Even on the free Beercalculus website.

Here's an explanation of how Beercalculus calculates it from their Hopville Blog;

Quote:

Previously, the default IBU calculation for Beer Calculus was based on an average of a few popular formulas. It did four calculations (Garetz, Rager, Tinseth, and the legacy Hopville calc) and averaged them together. I chose to blend a few conflicting numbers together instead of committing to a single one by default. That neutral position tended to cause some confusion among both types of brewers: those who cared which formula was in use, but didn’t know you could change it, and those who didn’t care at all. Plus, the only indication that a formula selection was being made was a subtle message “avg” near the IBU result – pretty vague about what was happening behind the scenes. Recipes now default to the Tinseth formula. Hopefully this will satisfy those who prefer this formula, and also clarify the default calculation to folks who don’t really care.

CPooley4 · 01-15-2011, 11:11 PM

The spreadsheet is set up with the Tinseth calculation. Tinseth recommends using an average boil gravity so I also set it up that way to keep it as accurate as possible. I've come across software that does not use the average boil gravity (just the preboil gravity) and that can alter the IBU's you'll see. Can't tell you what Beersmith uses or Hopville.

Keep in mind, the human pallette cannot distinguish between 5 - 10 IBU's (depending upon which article/study you read). Being off by 5 or less wouldn't concern me much. However, being off 9 is a bit much imo. Are you sure all 3 were using the exact same numbers/volumes?

For your recipe, I'm coming up with 59.37 IBU's using my spreadsheet assuming 7.5 boil volume and 6 batch size. If you switch it to 7.5 and 5.5 then I'm coming up with 63.16. If you switch it to 7.5 and 5 then you'd have 67.43. The batch size number (post boil volume number) is important as it can swing your IBU count due to the average boil gravity being used in the calculation.

Moody_Copperpot · 01-17-2011, 12:06 PM

That's right, I'm back at work so those are the numbers I'm seeing on your spreadsheet as well. I use all three builders because at different places i don't have access to one or the other. I found out that on hopville I need to enter the post boil volume instead of the preboil, that seems to have brought the numbers a bit closer together. Good tip on the IBU's too, CP! Your spreadsheet rocks!

CPooley4 · 01-17-2011, 04:52 PM

Thanks, I appreciate it.

I'm in the middle of a pretty extensive upgrade to it. Hoping to get the remainder of it finished today. Either way it should be done in the near future and I'll re-post it here and send you a copy directly via email.

Moody_Copperpot · 01-17-2011, 06:45 PM

Awesome, I'll keep my eye out for it. Thanks man!

prrriiide · 02-09-2011, 03:23 AM

I recently did several recipes on Hopville (because I didn't have access to BeerSmith on the computer I was on), and then later transferred them to BeerSmith. The IBUs were WAY off between the two. I checked, and BOTH were using Tinseth with identical AA %'s. Any idears of what might be doing that?

Moody_Copperpot · 02-09-2011, 11:48 AM

Yes I can tell you exactly what is doing that. Hopville has something called"Boil 4 avg gallons" in the hops section. It defaults to 4 gallons for some reason. You have to manually change that setting. What you do is take your preboil volume + your post boil volume and divide it by 2. So if you have 7 pre, 5.5 post it would look like this: 7+5.5=12.5 /2=6.25. 6.25 is what you'd enter there. I had the same issue with it until I noticed that section and emailed the creator to find out the proper number to plug in there.

stevedasleeve · 02-09-2011, 01:39 PM

IBU calculations are really hit or miss though, you should know, regardless what formula you use. There is a show on that - which confirms my experience - at basicbrewingradio which show some rather wild competing IBU numbers using the standard formulas compared to actual IBU measurements.

What is interesting is that there seems not to be much consistency even within a single formula: For one beer with many small additions at the end of the boil the IBUs might be reasonably accurate, but using the same formula for beer with, say, just a 60 minute and a 20 minute addition the IBUs come out wildly inaccurate.

My take on it is not to sweat it at all. If I want my recipe to be a bit more bitter I will usually add at the long end (60 minute or FWH) and treat late additions as flavor/aroma. But honestly I kind of feel like just calculating at all is a waste of time! IMHO if you measure something and it is wrong it is pretty much meaningless!

IMHO and YMMV
Steve da sleeve