IBU Q for Ace of Hefe

[Absolut_Ninja]

Just need someone to check my math;

Brewed a Reinheitsge-NOT Hefeweizen

3# Briess Wheat @ 60 min
.5 oz Siracha Ace 12% @ 60

Figure this gives me about 28.55, not counting the addition below

3# Briess Light @ 15 min
.5 oz Siracha Ace 12% @ 15

This should give me about 11.32.

I ended with 1.050 @ 72 F after topping off.

Them added together is 39.87 IBU. Close enough?

 

[Calder]

I don't have BeerSmith on this computer, but I would say your IBUs are wrong for at least the second addition.

 

[brtisbuck]

37.1 for 5 gallon batch/full boil

 

[aiptasia]

Beer recipator has you coming out at around 24 IBU. Are you using all extracts or are you using grains? Boil volume? Batch size? Are you using pellets or whole hops?

 

[Absolut_Ninja]

Thanks guys. I didn't think to list that stuff. I was using pellets, just under 5 gallon boil (prob about 4.75 so I wouldn't spill/boil over). I used all extract w/ some specialty grains, which is why I posted here. It need not be exact, just looking for a in the ball park range.

 

[frozt]

Was the extract dry or liquid? And is 1.050 the number you saw on the hydrometer at 72F or the corrected gravity given that it was 72F?

 

[frozt]

I went ahead and assumed you used DME and that the corrected OG was 1.051:

Estimated OG = ( (3×44)+(3×44) )÷5 = 52.8 = 1.052

Corrected Actual OG = 1.051

(4.75 gallon boil)
Boil gravity (Pre-Light-DME) = ( (3×44) )÷4.75 = 27.8 = 1.028

.5 oz Sorachi Ace 12% (60 min)
Util(60) = (1.65×(.000125^.028))×((1−(e^(−.04×60) ) )÷4.15) = 0.28109165 * 1.1 (pellets) = 0.309200815
AAU(Sorachi 60) = .5 oz * 12 alpha = 6 AAUs
IBU(Sorachi 60) = 6 AAU * 0.309200815 util. * 75 / 5 gal. batch size = 27.828 IBUs

Boil gravity (Post-Light-DME) = ( (3×44)+3×44 )÷4.75 = 55.58 = 1.056

.5 oz Sorachi Ace 12% (15 min)
Util(15) = (1.65×(.000125^.056))×((1−(e^(−.04×15) ) )÷4.15) = 0.108447788 * 1.1 (pellets) = 0.119292567
AAU(Sorachi 15) = .5 oz * 12 alpha = 6 AAUs
IBU(Sorachi 15) = 6 AAU * 0.119292567 util. * 75 / 5 gal. batch size = 10.736 IBUs

Total IBUs = 27.828+10.736 = 38.56 IBUs (Tinseth)

 

[Absolut_Ninja]

Awesome. Yes, I used DME & you were right about the hydrometer reading. I really appreciate following your math too!