I was wondering if there were certain hops that can be paired with each other, and ones that shouldn't. I am making a Nut Brown Ale extract soon and was going to use Cluster for the bittering, and Fuggles for flavor and aroma. However, I really like Amarillo and I have some extra in the freezer. Could I use the Amarillo with these two hops? I am using 1oz. Cluster, and 1oz Fuggles. I would like to raise the bitterness up just a bit so maybe an additional 1oz. Amarillo for the 60 minute boil? Also, is there a book or website that will explain hop varieties and which ones can be paired together?