Beersmith bittering calculations

[BrewHound]

I recently bought the beersmith app and I've been plugging in recipes to see how well the recipes I'm using are aligning to style and I noticed something odd about Jamil Zainasheff's Belgian Golden Strong Ale. IBU per the recipe will be 32 but when I plug everything in on beersmith I get 14.

8.4# pilsener lme
3# cane sugar
2.25 oz Czech Saaz 3.5%
90 minute boil

Is it me or is the app calculating incorrectly on this one? I've looked at other golden strong ale recipes and the hops look appropriate.

 

[McKnuckle]

The IBU estimate is contingent on boil volume and boil gravity. What are those figures in your example?

I get about 35 IBU with your data and a 6 gallon ending kettle target, OG of 1.067. My model adds the LME and sugar at the end of the boil, so they do not contribute to pre-boil gravity (ignore this for now).

 

[yeastylad]

Check your boil volumes, batch size, etc for your setup. That can have an effect. I plugged into beersmith on my phone, and it looks like you are assuming a 4 gallon partial boil for a 5 gallon batch, yeah? I got the same number. If you want higher without changing the hops, you'd have to do a full boil and late extract addition most likely, and add the sugar towards the end of the boil too. Otherwise, mod the recipe a bit and either change your bittering hop to something with more bittering potential, or have another addition, maybe 30 or 45 mins to up the IBUs if that's what you're looking for.

 

[hanuswalrus]

You also may need to adjust the actual AA% on your Saaz hops. I've had to do this pretty much every time I plug a recipe into Beersmith. The program will automatically plug in the "Typical AA%" from a given hop variety, but often times your actual AA% will differ.

Example: I used Warrior on my last IPA for bittering. If I recall correctly, Beersmith came up with 16-17% AA, when my Warrior hops were actually 18.5% AA. When I adjusted the actual AA%, my estimated IBUS went up by about 5 units if I recall correctly

 

[BrewHound]

Boil volume is based on a 4 gal kettle. I had missed that the cane sugar is added after the boil - that brought the estimated IBUs up to 18.5. I'm not sure about the pre boil gravity and how to calculate that.
That said, this is the first recipe I've had a problem with - figure it's me just can't figure out where. Maybe my technique for this brew has been off all along?!

 

[BrewHound]

When I say that this is the first problem, I mean getting the numbers to hit in the app.
:/

 

[BrewHound]

You also may need to adjust the actual AA% on your Saaz hops. I've had to do this pretty much every time I plug a recipe into Beersmith. The program will automatically plug in the "Typical AA%" from a given hop variety, but often times your actual AA% will differ.



Example: I used Warrior on my last IPA for bittering. If I recall correctly, Beersmith came up with 16-17% AA, when my Warrior hops were actually 18.5% AA. When I adjusted the actual AA%, my estimated IBUS went up by about 5 units if I recall correctly

Double checked this and it's on point.

 

[BrewHound]

And the solution is: it's me! My notes didn't reflect that half of the lme should be going in after the boil and I hadn't broken that down on the grain bill in the app. It's been a couple of years since I made this one and my note taking at the time wasn't what it should be.
Thanks for helping me dig into this!