Hop A/A Adjustment Strategies

[ChicoBrewer]

I started creating an American Wheat Ale based due to my recent score on Pilsen and White Wheat malt and TW's suggestion that I make an American Wheat Ale with it. I went and clipped a recipe from AHA and created a copy in the Recipe Editor. Here is the recipe. The original recipe claims 8.4 AA for the perle but the Perle I have from Hops Direct is 4.1. So the question is - Should I basically just double the 90 minute Perle addition to get the IBU's up to the ~13 the style wants? In general, how do you deal with hop additions when your source hops has a different AA value than suggested by the editor or when stealing a recipe?

 

[Hogarthe]

Original aa x weight ÷ new aa = new weight. I think I wrote that correct.

 

[ChicoBrewer]

That's it! Simple algebra LOL. Thanks!

 

[J A]

Just plug the proper ingredient values (the actual hops you will use) into the calculator and up the amount until it gets the IBUs you want. A recipe is nothing but a record of the ingredients used to create the beer. Hop AA values are not a constant - you could get 2 bags of hops right off the shelf with 2 different AA numbers.
Obviously, if you have hops of a different value than a particular recipe, you have to make that accommodation when entering data into the recipe editor.