Trouble getting the right IBUs out of Beersmith for a Partial Boil

I'm getting ready to do a Brewer's Best kit and convert it from partial to full boil with Beersmith. I decided to practice with the instructions from the last kit and make sure everything came out right. Well, it didn't and I'm wondering what I screwed up. Here's what I entered:

Brewer's Best Red Ale Kit:

Fermentables:
6.6 lb Amber LME
1 oz Chocolate
8 oz 120L Crystal

Hops:
1 oz Willamette (60m)
1 oz Willamette (5m)

Yeast:
1 pkg Danstar Nottingham

My OG is slightly off because they said "Light LME" and that wasn't on the list, and maybe because the grains were steeped and I didn't enter that right, but it was only 1.048 instead of the 1.050 that I got.

What I am worried about is that my calculated IBUs came out to 15.1 when the recipe calls for 21. Since I am going to use this to adjust the hop schedule, this is really the most important thing for me to get right.

I have my boil volume set to 2.5 gallons in a 4 gallon pot and my batch size set to 5.0 gallons, since the instructions say "IBUs for this recipe are calculated for a 2.5 gallon boil".

Am I missing something obvious? It is a slightly daunting piece of software to use at first and I probably entered something wrong. If it helps there's a PDF of the recipe here. It does say "bittering" and "aroma" for the hops, but I was on the ball enough to note that it was indeed Williamette when I made the kit. I've also got a screenshot of what I punched in. I've got work all day tomorrow, so please be a bit patient with me if I take a while to answer any questions you might have about what I did.

I get the same results as you do. The only thing I would note, is that you still have an OG of 1.048. The 1.050 you are referring to is just automatically generated by beersmith, but doesn't mean anything. You are actiually supposed to enter the actual OG you measure in that field and the FG you measure in the field below that. The program will then use those numbers to determine your actual ABV and calories/pint. The actual numbers the computer estimates for the recipe is to the left under Beer Profile. The only question I would have would be if you looked at both hop packages to see if both were willamette? Maybe they screwed up the calcs. Honestly, for 5.5% AA hops in a 2.5 gallon boil for 60 minutes, the hop calcualtion beersmith gave seems right.

Alright, thanks. The 1.050 and 1.010 are from when I actually did it. I may have actually not had both Williamette and written down only one.

Just to be sure, to convert to full boil I should enter my new starting volume in the "scale recipe" dialog, and that's it, right?

JerTheRipper said:

Alright, thanks. The 1.050 and 1.010 are from when I actually did it. I may have actually not had both Williamette and written down only one.

Just to be sure, to convert to full boil I should enter my new starting volume in the "scale recipe" dialog, and that's it, right?

Click to expand...

No. You're not scaling the recipe, you're changing the "boil volume". Right next to the "batch size" box, you just change the boil volume to however much you're boiling. Notice that the IBUs on the bottom left will change immediately.