Reaching Target IBUs - BYO Vermont Cult Clones

[BluesNBrews]

I was excited to see an article in the most recent BYO magazine highlighting some popular beers from Vermont breweries. I had a chance to visit the Alchemist brewpub before they closed after Hurricane Irene in 2011, so thought I would try brewing one of the two clone recipes from the article.

I'm concerned that the amount of hops the recipe calls for during the boil is not enough to generate the listed or targeted IBUs.

The Heady Topper recipe calls for only about 1/2 oz. of high alpha hops during the full boil, 1 oz. at 30 mins, and over 10 oz. added during flameout and during dry hopping. The recipe says the beer should come in at 100+ IBUs. Although I lack experience, it does not seem like enough to offset over 16 lbs. of grain/sugar and still be bitter.

The second Alchemist clone recipe in the article follows a similar hopping schedule during the boil.

I'd appreciate any thoughts the group has regarding what I should expect from a recipe like this. I'm sure if it's published, it will be on the mark, but I don't understand why.

Thank you, cheers.

 

[GarageDweller]

I haven't seen those exact recipes, but the clones i've seen for heady topper typically involve hop extract to minimize the amount of hop matter in the kettle. maybe add a few ml of hop extract to your boil to reach the IBU and then, of course, the late additions are for aroma. I just used quite a bit of extract in a DIPA and it helped, but there were still a ton of hops to deal with when pumping through the chiller.

 

[BluesNBrews]

Thanks, I might try extract. Ive been using a hop spider and have not had too many problems. Im still struggling with reaching the target IBUs.I loaded the recipe into BeerSmith and don't get the target gravity either. My homebrew shop loaded the recipe into their software and came out fine, very confusing.

 

[telejunkie]

For the target gravity, beersmith assumes an extract rate or 36 pg/p for british pale malt while byo is assuming an extract rate of 37 pg/p for the pale malt. I'm assuming your homebrew shop was using 37 as well.
For the hopping rate, one thing you need to calculate is the continued iso-alpha conversion of hops after the heat is turned off. Byo assumes roughly 10% utilization of alpha acids for a 30 minute whirlpool which is what this recipe calls for. The way to calculate that is make your KO hops a 15-min addition in the calculator and add 15 minute boil time to earlier additions. So you will get x amount of ibus from the boil, then an additional y ibus from the whirlpool phase. I get 110 ibus using Tinseth & 112 ibus from Rager using that as guidelines.

 

[wonderbread23]

No way Heady measures to 100+ IBUs... maybe calculated. I'm guessing the commercial beer uses a huge whirlpool addition which sits quite hot while they knockout to their fermenters. I would not be surprised if they get the majority of their IBUs from that addition.