Hello everyone,
Being the start of beer week I decided to end my brewing hiatus (I have a week off school too

). Going to brew an IPA and use up some hops that have been open for a year.
Anyways the recipe calls for 8 mL of Hop shot which I can't/don't want to purchase. Hop shot is suppose to adds 10 IBUs/mL so the total for the recipe is 80 IBUs.
So I'm going to replace the hop shot with 80 IBUs of columbus hops and I want someone to check my math before I ruin a batch of beer:
AAU = AA% * weight in oz
IBU = AAU * alpha utilization * 75
80 IBU = AAU * 0.21 * 75
AAU = 80 IBU / (0.21 * 75)
AAU = 5.079
5.079 = 10.9 * weight
Weight = 5.079 / 10.9
Weight = 0.465 oz = 13.2 g
Other info:
The recipe calls for hop shot to be added at 60 min.
OG = 1.060
I'm asking mostly because I've never tried to calculate IBUs before, I'm quite good at math. But it does seem be that 13.2 g of hops is not much for 80 IBU.