My buddy I brew with recently landed a pound of Belma hops, so we're going to brew a single-hop pale ale. It's kind of our first foray out of the "just follow the recipe" style of brewing. Pretty excited about it.
Since we've never subbed out hops in a recipe before (except for the occasional out-of-stock substitution), I was hoping somebody might help us out real quick.
The recipe we're basing ours on calls for the following:
-1 oz Nugget (@8.5% AA [which is odd considering the internet claims Nugget is usually much higher AA]) (bittering hop)
-1/2 oz Perle (flavor hop)
-1 oz Cascade (aroma hop)
-1/2 oz Cascade (dry hop)
My question is this: Belma's AA% is 9.8%. That's pretty close to the 8.5% bittering hop the recipe calls for, as well as 6-9.5% the internet claims Perle is (the recipe doesn't specify any other AA% other than the Nugget), but is higher than 4.5-7% the internet claims Cascade usually is. Should we just do a straight swap-out with Belma on the ones that are close? Should we alter the amount for the Cascade, since it's a little lower?
I guess the real question is: is there a general guideline for substituting hops with different AA%s?
Thanks in advance for your insight.