Frkleal,

PP will get back to you on that because I am not a expert with BIABacus. In the meantime remember this. Measuring IBU's is not like measuring in meters, yards or cubits. There you have a comparable exactness. IBU's are measured on three (highly inaccurate) scales. The job for most of us is to pick the scale the gives us the results we want. The fact is that most all measurements of IBU's are inaccurate.

BIABacus is the most accurate, (PP will tell you why) so in short. BeerSmith is wrong. But I defend it because all results are taken from a broken scale so all are inaccurate. The IBU count on beer you buy is total crap. What their label says means almost nothing. To a hop-head like me I want to believe them, but I know better. I have had some of my beers tested in a lab. The IBU's were not what BeerSmith calculated (by a long shot). No offense to BeerSmith because they are using Tinseth which is the most used.

Tinseth vs. Rager? In the same recipe the difference between Rager at (60 IBUs) and Tinseth (40 IBUs ) is huge!

For a guy that just was filling in for PP. I guess I am starting to sound like him.

[Bob, that is the best post ever! Just went to post what I wrote below and it said that a new post had been made. The only hole I found in your post was that there are actually more than three highly inaccurate measurements but that is totally petty stuff.]

Welcome to the forum Frk ,

This is a great question. (It's not a new one to many readers here but it is such a messy one to answer so other members here leave this stuff to me - lazy buggers )

Straight up I am going to say that the BIABacus is the correct result. But, I have been writing for several hours on the forum since I finished work today and I want to give you a good answer. Can you do a few things for me?

Great topic ,
PP

1. Search my posts for 'Rager, Garetz, Tinseth'? Look for a post with a BeerSmith pic.

2. Search my posts for 'errors' and 'formula'.

This might possibly lead you to answering your own question. Basically, assuming that you have set BeerSmith to Tinseth, the formula that Beersmith uses is incorrect.

I've sort of been polite about BeerSmith for many years but am getting less so. People like myself and 'chiller' have spent many hours asking BeerSmith to correct their formulas (and articles on BIAB). Pretty much nothing has been done. If it had been, this site certainly wouldn't have bothered developing the BIABacus.

So...

...let's make this a bit of a challenge.

Join the BeerSmith forum and ask exactly the same question that you asked here. See what answer you get. I can guarantee you that the Tinseth forum that the BIABacus uses is correct and the one that BeerSmith uses is wrong.

This site though is all about education, humour, exploring etc. Frk, the BIABacus is actually a lot better beer designer than BeerSmith. Let's pretend though that the BeerSmith formulas were actually correct. The BIABacus is still a way better designer because you have to think like a real brewer. Read this thread.