Again showing off the little noob inside me...
and then I found this:
no need to ask my question now
and then I found this:
GaryA said:You can adjust for AA% in a brew.
Make sure to look at the flavor profile of the hops you are going to substitute.
Standard IBU Formula
IBU = weight of hops in ounces x alpha acid % x utilization % volume of final batch in gallons x 1.34*
*constant to convert measurement into US standards
Example:
1 oz. of Northern Brewer (10% alpha acid) boiled for 60 minutes in a full-wort boil of moderate gravity wort for a five-gallon batch.
IBU = 1 x 10 x 30 / 5 x 1.34 = 44.77
Let's say you are using last year's recipe but the alpha acid of your hops has changed to 8% alpha acid. You will need to solve for the weight of hops with the new alpha acid percent. Rearrange the formula so that...
weight of hops in ounces =
IBUs desired x volume of final batch in gallons x 1.34* / alpha acid percent x utilization percent
*constant to convert measurement into US standards
oz. hops = 44.77 x 5 x 1.34 / 8 x 30 = 1.25 oz. hops
no need to ask my question now