Shifting hop amounts

[gregs765]

I am making a brown ale that calls for cascade and nugget as bittering
hops and fuggles as flavor/aroma hops. I noticed my organic fuggles
are significantly lower in alpha acids than what is listed in the
recipe (recipe: 4.7% vs. mine: 2.7%). Should I try to keep the same
amounts of hops in the aroma and flavor additions (.25 and .5 oz.,
respectively) and make my IBU adjustments with the bittering hops? Or
should I adjust the amount of flavor/aroma hops to match the targeted
AAU's?

My gut says to use the same amounts of hops to get the intended amount
of flavor and aroma, but I am not sure about the relationship between
alpha level and the amount of flavor/aroma imparted.

My other assumption is that I can substitute the bittering hops more
easily because they impart less character to the beer than the
flavor/aroma hops, as long as I get the IBUs right and pick a
less-harsh variety in the same ballpark. Basically, I don't have nugget, so I want to swap in another moderate- to high-alpha variety to make up the IBUs.

Any advice would be appreciated.

Greg

 

[pjj2ba]

Go with your gut. I disregard any IBUs that are supposedly generated by flavor and aroma additions. Alpha acids are as you said, used to calculate bitterness, it doesn't tell you how much flavor and aroma you will get.

The general consensus is that it doesn't make a big difference what hop you use for bittering. I think this might be a little bit of an over-generalization. For many styles the differences would be minor, especially if there are a lot of other flavors in the beer.

 

[homebrewer_99]

4.7 / 2.7 = 1.740 oz (of the 2.7 hops)

 

[gregs765]

Thanks for the feedback. Since this is a brown ale, the flavors should be rich enough to mask any minor differences in the character the bittering hops provide.

Now I just have to survive a very cold brewday tomorrow (high of 30 forecasted). But I need to get this batch brewed for the holidays. It won't be ready by Christmas, but should be ready (or at least in the bottle) by the time I visit my parents the next week. Mom always loves my brown ale, so I am making most of the batch for her. Am I a good son or what?

Greg