BeerSmith 3 vs BeerSmith 2 - IBU Calculations are MUCH lower

[cmreigrut]

I've been a long-time (home and pro) user of BeerSmith, and I have just moved over to using BeerSmith 3, but the calculations seem to be WAY off on IBU (of course, I can't tell if that's because BeerSmith 2 was way over and BeerSmith 3 is correct, or if BeerSmith 3 is way under and BeerSmith 2 was correct).

This seems to be the case regardless of my equipment (I have both our 10bbl production system with 140% hop utilization, and our 1/2 bbl system with 100% utilization), using the standard Tinseth forumula.

I still have both versions installed so I can compare them.  I just created a sample recipe on both systems:

• On the small system, with 25lb Pale 2 Row and 2oz Warrior 14.3% Alpha / 4.75% Beta (60 min), I get 43.4 IBU in BeerSmith 2 and 25.7 IBU in BeerSmith 3.
• On the large system, with 250lb Pale 2 Row and 16oz Warrior 14.3% Alpha / 4.75% Beta (60 min), I get 24.3 IBU on BeerSmith 2 and 17.3 IBU in BeerSmith 3.

I'm hoping this is a misconfiguration somewhere on my part, but as far as I can tell everything looks exactly the same...except for the IBUs.  And I'm not as worried about perception as I am trying to get the recipes "right" in BeerSmith 3 when I'm moving them between systems and also having to update alpha acids for new batches of hops.

Please help!

P.S.  Saw this post as well (so apparently I'm not alone), but there didn't seem to be any resolution:  http://beersmith.com/forum/index.php?topic=21765.msg77880#msg77880

 

[cmreigrut]

OK, so going back through both systems, I found that I had some (what I thought were) minor differences between the equipment profiles in BeerSmith 2 and BeerSmith 3.  Most of them were actually fairly minor--small changes we'd made to some of our profile settings.  However, the biggest issue was that we had set "Boil Elevation" to the accurate 5570ft here in Centennial, CO.  BeerSmith 2 didn't have that setting.  When I change the elevation back to 0ft in BeerSmith 3, the estimated IBUs go back up to their original BeerSmith 2 values.
Thanks to the post http://beersmith.com/forum/index.php?topic=18829.msg69359#msg69359 for giving me the idea to look there.

That being said, I don't think the new calculations are correct, but I'm only going based on anecdotal data as we haven't had our IBUs tested in a long time (and I can't find the data from the one time we actually did have the test done).