May 11, 2013

get rich or die tRYEing Imperial Stout

The bold and rich flavors of an imperial stout should not be an excuse for making a beer with every grain in your local homebrew shop. In addition to walloping your taste buds with rich flavor, an imperial stout should also have a lot of complexity to extract out, with lots of subtle flavors available to tease out of the beer, especially as it warms up. Adding too many types of grain, a plague many homebrewers inflict upon themselves, can result in a beer with a few good notes but a muddy background that loses the more subtle flavors. A bigger beer like imperial stout can benefit from a more complex grain bill than smaller beers but there's a balance to find between layering flavors and creating a muddy beer. A simple grain bill can also produce a fairly complex beer if you put the work into using your brewing process to create other flavors (e.g. long boils, complex mash schedules).

Another important consideration in designing an imperial stout (and really, any beer), is how you plan on drinking it. If you are going to bottle or keg your stout for consumption 1-2 months after brewing then the recipe needs to be designed for early smoothness so you're not drinking a rough, boozy mess. The tradeoff will be a less impressive beer should you decide to age it because you're putting the mellowness age would provide into the recipe and it can get too mellow and a little bland over time. That means less acrid dark malts, like carafa and chocolate or midnight wheat, should take up a bigger portion of the grain bill dedicated to dark/roast grains. However, if you plan on aging your stout for months before drinking then the recipe needs to come into primary fermentation more bitter to stand up to the aging and with some more roasty character that can smooth out and blend nicely into a beer that will be nicely drinkable in months but may not peak for a year or two. Of course if you are going to barrel age you should take into consideration both the aging and the flavor contributions of the barrel.

This imperial stout was designed for aging at least a few months, if not more. It's destined to fill one of my party pigs as a cask beer for a good reason to stay at home on cold winter nights. A small amount will go into bottles to see how they age over time. The cask portion is getting brewed mid-May and probably won't get "tapped" until November or December. I have February's barleywine getting bottled later this month for late fall drinking that should satiate my need for a big beer early in the winter, along with my ever-growing collection of craft beer. So with that key goal in mind, let's turn to actually discussing the recipe formation.

Designing the recipe

As you can tell by the name of the beer, a tasteless pun using "rye" and appealing to the dark character of the
I will shoot the beer nine times for authenticity
beer, this imperial stout has rye character coming its way. I like the idea of rye in an imperial stout because it not only adds the rye flavor that I am really enjoying at the moment but it also lends that spicy character that helps cut through some of the richness of an imperial stout that can make them feel heavy and even a touch cloying. With a growing diversity of rye grains on the market, it's easy to create an interesting layered rye flavor to go along with the layer dark malt flavors in the stout.

Rye imperial stouts are not made by many breweries but Great Divide's Yeti (and numerous Yeti variants) is an excellent example of such a beer. In researching my recipe for a rye imperial stout it seems like every homebrewer begins their recipe with a clone recipe of Yeti. There's some disagreement online what the "right" clone is but everybody seems happy with their version even if they decided it wasn't an accurate Yeti clone. Unfortunately I did the research a while ago and forget exactly which clone recipes I thought were most accurate or produced the best beers, so I'm not sure where to point somebody for a good clone (although the BYO version is probably a sufficient starting point).

Like Yeti, I wanted the typical stout character to drive the beer but allow the rye to mold the stout flavors into something rye-laden and unique. To do that I wanted to build two complimentary layering of flavors. One would be the "stout flavors" with roast, some dark fruit, chocolate, etc. So I kept a solid roasted barley backing and layered in smaller amounts of chocolate malt, crystal 120 and black malt. The rye will come through in two ways to bring a more complex rye character. Flaked rye will provide some of the raw rye flavor and add body in place of flaked barley. Chocolate rye will provide some of the malted rye flavor (which is more predominate than unmalted rye) and add some interesting character to the darker malt flavors while adding to the complexity of the rye flavor. Add some two row as a base and you have just seven malts bringing a lot of complexity.

I'm not interested in getting hop character coming through in the beer because with time and cask pours, any flavor or aroma hops are going to diminish with time and low carbonation. There's enough going on with the malts to drive good beer flavor. Some chinook or other piney hop would make a good fit for later additions, like Yeti, but I want to see how the grains work together on their own and in the future I might add late hops for some added complexity. Here, Belma is added as both a first wort hop and sixty minute addition for bitterness and just a touch of flavor from the first wort hops.

The fermentation schedule will be very straight forward. It's going on the cake of S-04 from the Ugli Ass American Wheat and ferment at 63F for 10-14 days and then bulk age at room temperature for 3-4 weeks before transferring to the party pig for further conditioning. About half a gallon will go into bottles because the pig only holds about 2.5 gallons. I considered doing some oak treatment to the beer but just like I wanted to keep the hops to a minimum I want my first attempt at this recipe to be straightforward to get the malt bill right. Like Yeti, future versions may get diversified treatment.

Finally, the recipe

Batch size: 3 gallons
Est. OG: 1.091
Est. FG: 1.019
ABV: 9.5%
SRM: 71.4
IBU: 49.3
Est. efficiency: 72%

Grain bill:
8 lb. US 2 row (2 SRM) 74%
1 lb. Flaked rye (2 SRM) 9.2%
10 oz. Roasted barley (300 SRM) 5.8%
8 oz. Chocolate rye malt (250 SRM) 4.6%
7 oz. Crystal 120L (120 SRM) 4%
2 oz. Black patent malt (500 SRM) 1.2%
2 oz. Chocolate malt (350 SRM) 1.2%

Mash & Sparge:
Mash water volume: 3.38 gallons
Sparge water volume: 1.67 gallons
Mash schedule:
Single infusion of 3.38 gallons at 163.7F for 60 minute mash at 152F
Sparge schedule:
Batch sparge at 168F in two stages

Water supply:
100% RO water with mash and sparge mineral additions
Water profile: (London-like)
Calcium: 60ppm
Magnesium: 10ppm
Sodium: 21ppm
Sulfate: 41ppm
Chloride: 45ppm
Bicarbonate: 161ppm

Mash water: 3.38 gallons
Epsom salt: 1.4g
Kosher salt: 0.7g
Calcium chloride 0.3g
Chalk: 1.7g

Sparge water: 1.67 gallons
Gypsum: 0.6g
Epsom salt: 0.7g
Kosher salt: 0.3g
Calcium chloride: 0.9g

The Boil:
Boil time: 75 minutes

Hop additions:
0.30oz Belma [12.1% AAU] at first wort hop
1 oz Belma [12.1% AAU] at 60 minutes

Other boil additions:
3/4 tsp irish moss at 10 minutes

Fermentation schedule:
Cool to 63F and pitch on yeast cake
Ferment at 63F for 7-10 days (until gravity is stable)
Bulk age at ambient for 3-4 weeks
Bottle at 2.3 volumes

Brewday & Fermentation Notes:

First runnings: 19.8 brix or 1.0821~ 2.5 gallons
Pre-boil volume: 4 gallons
Pre-boil gravity: 1.063
Calculated mash efficiency: 66%
Post-boil OG: 1.075
Post-boil volume: 3 gallons

Gravity reading 5/21/13: 9.8 brix on refractometer, adjusted to gravity at 1.015, good for 8.2% ABV. May see a point or two drop over the next week but otherwise expect FG is reached. Beer is tasty but has slight alcohol burn. Expected to mellow out with aging. Looking at bottling in another 2-3 weeks.


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