Alright, I’m having a hard time here… I’m trying to calculate how many ounces of hops to use to reach a KNOWN IBU. However, all the equations I come across are the other way around, i.e. you have a known amount of hops and you’re looking to determine the IBUs. I know it’s just a simple re-arranging of the equation, but my math skills have gone out the window, apparently, and I can’t figure it out.
For my equation, I’m looking to determine how many ounces of Chinook to use (AA 11.4%) at 60 minutes (start of the boil) to reach an IBU of 40. Hop utilization at 60 minutes for an OG of 1.050 is 0.231.
Thanks chertel! That’s exactly what I needed. I’ve been going over the chapter in Palmer’s for a while now, and just couldn’t figure it out. Like I said, my math skills are dwindling. And uncdeo, the batch size is 5 gallons, which I forgot to mention.
Dont worry. Me same thing going over the math in the book from palmer. Me work lots with formulas. At my work. But reading. Stuff. Wondering where it starts or comes from. The numbers. So me using now brew software
Hmm… here’s what the Taylor method gets (should be similar to Tinseth):
(40-1.5)/3.6/11.4 = 0.94 oz
The 1.5 and 3.6 are some magical equation constants that I determined on my own. As you can see, they seem to work pretty well. Anyway, all IBU calculators come out a little bit too high as compared with actual laboratory results, so you may find that you actually do need the 1.01 oz or even a bit more if you were to measure in a lab. But we’re all in the same ballpark.