So I'm brewing again for the first time in about 2 years.  I'm really excited.  I've decided to go with Janet's Brown as my first recipe.
The question is about substituting hops.  I have *a lot* of Centennial and Cascade hops (thank you Ironman).  I would like to substitute them for the Northern Brewer.  I'm just not 100% sure how I want to to.  I'm basing it off the recipe here.  So the original hop schedule, to repost it, would be as follows.
Amount Name Form Alpha IBU Boil Time
-----------------------------------------------------------------------------
1.00 oz. Northern Brewer Pellet 6.50 19.0 Mash H
1.25 oz. Northern Brewer Pellet 6.50 30.8 60 min.
1.00 oz. Northern Brewer Pellet 6.50 6.6 15 min.
1.50 oz. Cascade Pellet 6.00 6.8 10 min.
1.50 oz. Cascade Pellet 6.00 0.0 0 min.
2.00 oz. Centennial Pellet 9.00 0.0 Dry Hop
I'm sure it will still be a good beer however I substitute.  I'm just looking for suggestions on what people may think the best choice is.  Thanks.
				
			





