Haast's Eagle Imperial IPA

Artist's rendition of a Haast's Eagle,
about to mess up some Moa in
prehistoric New Zealand. Art by John Megahan.

Imperial IPAs are, really, what took me from occasional beer enjoyer to beer fanatic and homebrewer. I think I can even single out the Great Divide Hercules Imperial IPA as the culprit. It's huge, punchy, and holy hops is that flavor strong! Citrus! Pine! Could it strip paint? Probably, and I wouldn't have it any other way! I think it's fitting then that the first recipe I made on my own and brewed successfully is an imperial IPA.

Those yellow clusters are called lupulin glands. That's
where all the resins and oils that give hops their
bittering and flavor/aromatic properties reside.

The inspiration for this IPA in particular came from perusing hops on the Northern Brewer site. At the time I had just started really reading about brewing beer, and knew what alpha acid is, and I had some idea about the other oils in hops that lend flavors to beer. I was looking through all these different hop varieties for a change of pace. I've had plenty of piney, citrusy IPAs, and I love them, but I wanted something a little different*. 

Turns out New Zealand is quite well known for its hop-growing climate, and has some really cool varieties that have been propagated there! Since I knew I wanted to make an imperial IPA, I focused on the high alpha acid hop varieties of New Zealand provenance. I settled on Pacific Gem and Nelson Sauvin. Both of these hops have really good bittering capability. Pacific Gem is the bittering workhorse of this beer, while Nelson Sauvin comes in later to provide bitterness and hop flavor+aroma. These high alpha acid hops are brought together for a beer that punches in at just over 90 IBUs (international bittering units). For those who are wondering what that number means exactly, Bud Light weighs in at 6.4 IBUs. The higher the IBUs, the more bitter the beer will be.  

This is a Harpy eagle, crouching and being gigantic on this guy's arm.
The Haast's eagle was about 1/3 larger! Also, check out the talons!

This brings me to the namesake of the beer. Originally I was going to call this one "Moa", but it turns

Pretty impressive, considering just how
huge Harpy eagles are.

out there is a brewery in New Zealand called Moa. So in the interest of not ruffling anyone's copyright feathers, I went for the lesser known but definitely more badass Haast's eagle (Harpagornis moorei). An eagle of nearly Tolkein-esque proportions, the now extinct Haast's eagle is believed to be the heaviest member of the Accipitridae, the family which includes eagles, hawks, Old World vultures, and kites.  Female Haast's eagles were larger and heavier than the males, weighing an estimated 31 pounds, with an 8.5 foot wingspan; estimates for male Haast's Eagles place them at 25 pounds, with a presumably smaller wingspan (Braithwaite 1992; Worth and Holdaway 2003). 

On the left is a Haast's eagle talon, compared to a Little eagle
talon on the right. Little eagles are a member of the genus
Hieraaetus, which was found to contain the closest
living relatives to the Haast's eagle by Brunce et al. 2005. 

Using recovered mitochodrial DNA from Haast's Eagle remains, Dr. Michael Brunce and his colleagues created a maximum likelihood phylogenetic tree to determine a possible ancestral origin for the massive bird of prey (Brunce et al. 2005). In an interesting twist, the Haast's Eagle is most closely related to the diminutive eagle genus Hieraaetus (Brunce et al, 2005). This implies a remarkable increase in size from the hypothesized ancestors of the Haast's Eagle, and provides an excellent example of island gigantism! Also of note is that the Haast's Eagle becomes giant while retaining the ability to fly. Most birds, such as the moa, elephant bird, and the dodo, all become secondarily flightless when they increase drastically in size, owed to a lack of terrestrial predators on their home islands as they were evolving (Brunce et al, 2005). Without any large mammalian carnivores around, Haast's eagles were almost certainly the dominant predator of the South Island of New Zealand, terrorizing the moa birds native to the island until the arrival of humans in approximately 1280 AD. Haast's eagles are believed to have gone extinct around the year 1400 AD, following the devastation of its food sources and broader ecosystem by humans (Allentoft et al. 2014). 

The red text shows the position of the Haast's eagle (Harpagornis moorei) among other birds of prey, including the Little eagle. Image from Bunce et al. 2005.

 


*Not to say I didn't order some punchy pine and citrus flavored/aroma hops for other beers I am working on...

Haast's Eagle Imperial IPA

Type: All Grain

Batch Size:  1.10 gal

Boil Size:  1.64 gal

Boil Time:  60 min

End of Boil Vol: 1.14 gal

Final Bottling Vol: 1.10 gal

Fermentation: Ale, Two Stage

Brewer: David Levering

Asst Brewer: Medhavi Ambardar

Equipment: David's Brewing Equipment

Efficiency: 60.00 %

Est Mash Efficiency: 60.00 %

Prepare for Brewing

Clean and Prepare Brewing Equipment

Total Water Needed: 2.13 gal

Water Prep

Amt

Name

Type

%/IBU

2.13 gal

Distilled Water

Water

-

0.63 tsp

Gypsum (Calcium Sulfate) (Mash 60.0 mins)

Water Agent

-

0.30 tsp

Calcium Chloride (Mash 60.0 mins)

Water Agent

-

0.22 g

Epsom Salt (MgSO4) (Mash 60.0 mins)

Water Agent

-

Mash or Steep Grains

Mash Ingredients

Amt

Name

Type

%/IBU

3 lbs 1.3 oz

Pale Malt (2 Row) US (2.0 SRM)

Grain

72.00%

9.6 oz

Pale Malt, Maris Otter (3.0 SRM)

Grain

14.00%

4.8 oz

Caramel/Crystal Malt - 20L (20.0 SRM)

Grain

7.00%

1.6 oz

Caramel/Crystal Malt - 80L (80.0 SRM)

Grain

2.30%

Mash Steps

Name

Description

Step Temperature

Step Time

Mash In

Add 5.10 qt of water at 159.1 F

148.0 F

75 min

Batch sparge with 2 steps (0.04gal, 0.82gal) of 168.0 F water

Add water to achieve boil volume of 1.64 gal

Estimated pre-boil gravity is 1.059 SG

Boil Ingredients

Amt

Name

Type

%/IBU

3.2 oz

Candi Sugar, Clear (0.5 SRM)

Sugar

4.70%

0.10 oz

Pacific Gem [15.00 %] - Boil 50.0 min

Hop

22.7 IBUs

0.10 oz

Pacific Gem [15.00 %] - Boil 30.0 min

Hop

18.4 IBUs

0.10 oz

Nelson Sauvin [12.00 %] - Boil 20.0 min

Hop

11.6 IBUs

0.20 oz

Nelson Sauvin [12.00 %] - Boil 10.0 min

Hop

13.9 IBUs

0.20 oz

Pacific Gem [15.00 %] - Boil 10.0 min

Hop

17.3 IBUs

0.10 oz

Irish Moss - Boil 15.0 min

Clarifier

Steeped Hops

Amt

Name

Type

%/IBU

0.10 oz

Nelson Sauvin [12.00 %] - Steep/Whirlpool 10.0 min

Hop

3.5 IBUs

0.10 oz

Pacific Gem [15.00 %] - Steep/Whirlpool 10.0 min

Hop

4.3 IBUs

Estimated Post Boil Vol: 1.14 gal and Est Post Boil Gravity: 1.088 SG

Cool and Transfer Wort

Cool wort to fermentation temperature of 70 F.

Transfer wort to fermenter

Add water if needed to achieve final volume of 1.10 gal

Pitch Yeast and Measure Gravity and Volume

Fermentation Ingredients

Amt

Name

Type

%/IBU

0.2 pkg

London Ale Yeast (Wyeast Labs #1028) [124.21 ml]

Yeast

-

Starting Gravity Target: 1.088

Add water if needed to achieve final volume of 1.10 gal

Fermentation

Primary Fermentation (4.00 days at 67.0 F ending at 67.0 F)

Secondary Fermentation (17.00 days at 67.0 F ending at 67.0 F)

Dry Hop and Bottle/Keg

Dry Hop/Bottling Ingredients

Amt

Name

Type

%/IBU

0.20 oz

Nelson Sauvin [12.00 %] - Dry Hop 7.0 Days

Hop

0.0 IBUs

Final Gravity Estimate: 1.013

Date Bottled/Kegged: Carbonation: Bottle with 0.86 oz Corn Sugar

Age beer for 14.00 days at 65.0 F

Age beer another 14 -21 days at 45-50 F.

Notes

Additions to be made to the heated water before it is mixed with the malted grains:

Gypsum: 0.63tsp

CaCl2: 0.2tsp

Epsom Salt: 0.22tsp

Phosphoric acid addition: 2tbs

Dry hops should be added using a muselin bag to prevent them from creating a mess inside the fermenter. This is especially true if using pellet hops. Make sure the fermenter is well sealed during the dry hopping phase to prevent volatile aromatics from escaping the beer. The first 4 days of the dry hopping should happen at around 65 degrees F. For the final 3 days, cold crash the fermentor to 40-50 degrees F. Before bottling, remove the muselin bag full of hops from the fermenter.

 

References

Brathwaite, D. H. 1992. Notes on the weight, flying ability, habitat, and prey of Haast's Eagle (Harpagornis moorei). Notornis (Ornithological Society of New Zealand), 39: 239–247.

Bunce, M., Szulkin, M., Lerner, HRL., Barnes, I., Shapiro, B., Cooper, A., Holdaway, R.N. (2005) Ancient DNA Provides New Insights into the Evolutionary History of New Zealand's Extinct Giant Eagle. PLoS Biol, 3: e9.

Worthy, T. & Holdaway, R., The Lost World of the Moa: Prehistoric Life of New Zealand. Indiana University Press (2003).

Allentoft, M.E., Heller, R., Oskam, C.L., Lorenzen, E.D., Hale, M.L., Gilbert, M.T.P., Jacomb, C., Holdaway, R.N., Bunce, M. 2014. Extinct New Zealand megafauna were not in decline before human colonization. PNAS, 111: 4922-4927