Imperial Stout: Back in black
When the weather starts turning cool, I immediately think of brewing and drinking big, rich beers. Sure, winter warmers, old ales, and barleywines will do the job, but when I want to turn it up to 11, my focus turns to that Darth Vader of beer styles, imperial stout. Historically, it was a strong English beer that was exported to the Russian Empire, but today it is a popular craft beer style in the U.S. and elsewhere in the world. It often serves as the base style for barrel-aged beers and beers with special ingredients.
The traditional English and modern American takes on the style often leads people to think that the style has two main variants. Indeed, the Brewers Association recognizes those substyles during Great American Beer Festival judging, just like barleywine and IPA are separated. However, the Beer Judge Certification Program (BJCP) treats it as a single style representing the continuum between these variants since there are many examples that freely mix English and American ingredients and techniques. Rather than create a third hybrid style, it was easier to acknowledge the historical division and then explain the full range of the style.
The BJCP classifies imperial stout as style 20C, in the American Porter and Stout judging category, along with American porter and American stout. This grouping was somewhat controversial since many rightly point to the historical English roots of the style. However, I choose to group it here because style categories are intended for judging purposes, and imperial stout actually judges well against those other two styles. In the 2008 and prior guidelines, Russian imperial stout was grouped with all other stouts, which led to lower-gravity styles being neglected. Ordinary bitter isn’t judged alongside English barleywine, is it? The same logic applies here.
Imperial Stout History
Stout in general evolved from porter, an English beer style since the early 1700s. Originally called stout porter meaning a stronger porter, it subsequently split into several styles. Irish stouts split from English stouts and became influential and popular, due in no small part to the efforts of Guinness. But what is known today as imperial stout has its roots in the double brown stouts (or extra stout porters) of London.
The Anchor Brewery in the Southwark district of London on the south bank of the River Thames is often named as one of the first popular exporters of the beer style. They are known to have exported it to the Russian Empire and other countries on the Baltic Sea as early as 1781. Catherine the Great was empress of Russia from 1762 to 1796, and she and her court were said to enjoy the high strength beer. Thrales owned the Anchor Brewery until it was purchased by Courage in 1795.
Barclay Perkins and other London porter brewers such as Reid, Whitbread, and Truman also produced and exported the beer. Barclay Perkins much later merged with Courage in 1955. They were known for producing the Courage Imperial Russian Stout, which was the last surviving English example, produced until 1993 before being resurrected by Wells & Young’s in 2011. Bass was known for their P2 Imperial Stout, a fairly limited production not as well known as their P1 Barleywine.
Some businessmen bottled and exported beers from England, much like modern distributors. Albert Le Coq, a Prussian of French origin, is associated with this trade, as his company exported Barclay Perkins (later Reid) Imperial Extra Double Stout during the 1800s before buying a brewery in modern Estonia in 1912 to supply the Russian market. Michael Jackson mentioned this beer, which led to its reintroduction in 2000 after years of decline during the Soviet era. Interruption of trade during the 1800s, especially in the Napoleonic era, helped lead to the development of modern Baltic porter, a spin-off of these early imperial stouts.
The microbrew boom in the U.S. led to early brewers making versions of this style that Michael Jackson described. Grant’s (opened in 1982, now Yakima) was one of the first. Rogue and Great Lakes were mentioned as early producers, although neither currently makes the style. Bell’s Expedition Stout (first made in 1989) and North Coast Old Rasputin (first made in 1995) are perhaps the best-known U.S. examples still made today. Samuel Smith’s in England began making the beer in the 1980s for the U.S. market in response to this demand. Much later, Fuller’s also introduced a limited-edition example.
Historically, it was a strong English beer that was exported to the Russian Empire, but today it is a popular craft beer style in the U.S. and elsewhere in the world.
Today, many U.S. examples are barrel-aged or involve specialty ingredients. One such example I enjoy is Cigar City Hunahpu’s Imperial Stout with cinnamon, vanilla, cacao nibs, and chili peppers. During my travels, I often see examples in South America and elsewhere, showing the global reach of modern craft beer. I have had wonderful examples in Brazil that were aged in Amburana wood.
Sensory Profile
Imperial stout is properly known as the richest and strongest of the stouts. So much that imperial has become a modern adjective for other beer styles meaning big, not its historical meaning of brewed for emperors. The overall balance can vary, but it has intense flavors — always with a strongly roasted emphasis — is very strong and always dark. Like all stouts the color is black, typically very dark and opaque. The head will generally be well-formed and have a brownish color. The 8% and higher alcohol level should be noticeable, but not burning, and the body is typically quite full with a chewy, velvety texture.
The roasted quality expresses itself in different ways, such as coffee, dark chocolate, cocoa, black licorice, or even tar. There may be caramel, dried dark fruit, or biscuity notes present. Hop flavors may or may not be present, and can be of almost any variety that adds to the complexity. There may be a bit of alcohol flavor sneaking in, but it should not be prominent. These qualities are apparent in both the flavor and the aroma. The intensity level and balance between these components are subject to brewer interpretation and can vary quite a bit as long as they all blend coherently.
The balance of sweetness and bitterness can vary with the overall bitterness ranging from moderate and balanced to quite aggressive. The finish can seem fairly dry to moderately sweet, but shouldn’t be syrupy or cloying. Age often affects this balance with flavors mellowing and body diminishing over time. The strong flavors should last into the aftertaste, along with a warming impression.
The overall impression may seem “English” or “American” or somewhere in between. English versions tend to be more estery and often have a more tarry flavor, while American examples can favor more of a late hop character and clean fermentation profile. Both acceptable, as are those that blend any of these components.
Brewing Ingredients and Methods
It’s hard to describe how to make an imperial stout without sounding like anything goes. I think the fermentables can be divided into four groups: Base malts, dark malts and grains, crystals and sugars, and adjuncts. My recipes often include something from each group, but I have seen recipes as simple as three ingredients (pale malt, roasted barley, chocolate malt). On the other end of the spectrum, I’ve seen recipes with more than a dozen ingredients in the grist. Both have won significant medals, so whatever approach is taken, it’s the flavor that matters.
Historical English versions often use some combination of pale malt, amber malt, brown malt, black malt, and dark brewing sugars (well, depending on the year — remember black malt wasn’t invented until 1817). The pale malts were often pale ale malt but could be the more dextrinous mild or stout malts. Sugars were usually dark invert sugars (#2 through #4), not white table sugar, and provided many of the flavors that modern brewers get from dark crystal malts. Roasted barley, chocolate malt, and crystal malts were not common English ingredients in this style historically, although it’s not uncommon for them to show up in modern incarnations.
Americanized versions can use a neutral base malt or something bready and biscuity like Maris Otter. Those wanting added maltiness often find a way to sneak in Munich, Vienna, or other character base malts, sometimes accenting with biscuit, Victory®, or similar malts that give British flavors akin to amber and brown malts. Dark malts and grains are normally at least two of roasted barley, chocolate malt, and black malt. Crystal malts skew to the higher Lovibond colors, 60 and higher, up to 160, maybe with some Special B for raisiny notes. Starchy adjuncts are often flaked oats or barley for body, maybe with some wheat malt for head retention. Flavors of crystal and dark malts can vary quite a bit between maltsters, so you may want to compare flavors before making your final selection.
Looking at all the recipes I’ve used over the last 25 years, I see base malts in the range of 70–80% of the grist, adjuncts between 0–5%, crystal and sugars in the 0–15% range, and dark grains at 10–20%. The balance and composition of these are your choice. I tend to think about the dark flavors first, and the finishing gravity and bitterness next to determine the overall balance. Remember that sweetness masks many flavors so keep that in mind if your finish gravity is on the high side. I prefer mashing at lower conversion temperatures (151 °F/65 °C or lower) to encourage attenuation, knowing that any crystal malts and starchy adjuncts will provide the body and sweetness, but many people will mash higher (154–158 °F/68–70 °C) if they do not use these in the grist.
The hop character can vary greatly with the bitterness level being your first choice. IBUs are typically between 50 and 90, although there are some commercial outliers on either end. If I’m making an English style, I tend towards the low side, while American versions can go higher. Remember that if you are intending to age the beer, you might want to overshoot the hop character so it ages into balance. That was often my strategy when I was actively competing. Some late hops work in the style, and can be low to high. English or American varieties are classic, and many of my recipes use Chinook, Centennial, and Golding for piney, citrusy, and floral notes. The beer may or may not be dry hopped; it can certainly take it.
Neutral American or fruity English yeasts are common, as long as they can handle the alcohol levels (often 10% or more) without leaving the beer cloying or generating too many higher alcohol byproducts. I tend to prefer attenuative strains while using the grist to drive the body and sweetness of the beer, not lower residual extract. But I also know people who have successfully used yeast stains that are described as favoring malty beers, and some have used Scottish or Irish strains. Some pitch lager yeast when the beers will go through extended secondary aging. Fermentation temperatures are in the normal range for whatever yeast is selected; don’t try to use higher temperature fermentations as these often stress the yeast. Use larger pitch rates appropriate for higher gravity beers; I typically double the yeast of a normal-strength beer or repitch from a standard-strength beer.
Homebrew Example
I’m presenting an English-inspired version with some American hopping. The base malt is Golden Promise, but any English pale ale malt can be substituted. Maris Otter isn’t necessary since the other flavors will be quite strong. A good English brown malt like from Crisp or Fawcett will add some of that porter-like flavor. Oats will help provide some body, while the mash temperature remains at a moderate level to encourage attenuation. My friend Joe Formanek sometimes decocts his base malts; if this process appeals to you, now is a good time to use it.
I’ll use all three of the typical dark grains, including roasted barley as the highest percentage with chocolate and black malt. I like using English maltsters here as well. Instead of a collection of crystal malts, I’ll use invert #4 or the closest equivalent I’m likely to find, a Belgian candi syrup of 180L color. These will give the fruity and dark sugar flavors without having to use four or five different crystal malts.
The mash method is my typical approach, including lower levels of minerals and adding the dark grains during the vorlauf. This step is pretty important, since it helps the mash pH be in a predictable range and reduces the harshness extracted from the dark grains. Just be sure to recirculate for the full time, and conduct a slow sparge as well. A short steep won’t cut it; that recirculation and sparge time is when the color and flavor is rinsed from the dark grains.
I’ll use three additions of hops — traditional bittering, flavor, and aroma additions: Centennial for bitterness, Chinook for flavor, and Golding for aroma. I have used first wort hopping before with non-traditional styles; it worked with Chinook. I have also moved the aroma addition to dry hops previously. I mention these only as options.
I like a dry English yeast in this style and Wyeast 1028 (London Ale) fits the bill. Any other attenuative English strain could serve a similar purpose including dry yeast like LalBrew Nottingham or SafAle S-04. Making a starter with a large smack pack or repitching from a prior batch is what will give you enough yeast (or use two large packs or an extra sachet), and I’d always oxygenate this beer when reusing yeast or pitching a starter to encourage a quick start to fermentation.
With this level of alcohol and dark grains, I’d cellar it for at least six months before serving. It will age well for years if your sanitation and packaging game is solid. So brew one now for next winter’s enjoyment.
Imperial Stout by the Numbers
OG: 1.075–1.115
FG: 1.018–1.030
SRM: 30–40+
IBU: 50–90
ABV: 8–12%
Imperial Stout
(5 gallons/19 L, all-grain)
OG = 1.100 FG = 1.026
IBU = 61 SRM = 111 ABV = 10.8%
Ingredients
13.25 lbs. (6 kg) Golden Promise pale ale malt
1.75 lbs. (794 g) U.K. brown malt
0.5 lb. (227 g) flaked oats
2 lbs. (907 g) U.K. roasted barley
1.25 lbs. (567 g) U.K. chocolate malt
0.75 lb. (340 g) U.K. black malt
2 lbs. (907 g) Belgian extra dark candi syrup (180 °L) (15 min.)
21 AAU Centennial hops (60 min.) (2 oz./57 g at 10.5% alpha acids)
13 AAU Chinook hops (15 min.) (1 oz./28 g at 13% alpha acids)
1 oz. (28 g) U.K. Golding hops (5 min.)
Wyeast 1028 (London Ale), White Labs WLP013 (London Ale), LalBrew Nottingham, or SafAle S-04 yeast
3⁄4 cup corn sugar (if priming)
Step by Step
This recipe uses reverse osmosis (RO) water. Adjust all brewing water to a pH of 5.5 using phosphoric acid. Add 1 tsp. of calcium chloride to the mash.
This recipe uses an infusion mash. Use enough water to have a moderately thick mash (1.5 qts./lb. or 3.1 L/kg). Mash in the pale and brown malts and the oats at 151 °F (65 °C) and hold for 60 minutes. Add the three dark grains, stir, begin recirculating, raise the mash temperature to 169 °F (76 °C), and recirculate for 15 minutes.
Sparge slowly and collect 6.5 gallons (24.5 L) of wort.
Boil the wort for 90 minutes, adding hops at the times indicated in the recipe. Add the candi syrup when 15 minutes remain in the boil.
Chill the wort to 64 °F (18 °C), pitch the yeast, and ferment until complete, allowing the temperature to rise as high as 70 °F (21 °C).
Rack the beer, prime and bottle condition, or keg and force carbonate.
Imperial Stout
(5 gallons/19 L, extract with grains)
OG = 1.100 FG = 1.026
IBU = 61 SRM = 100 ABV = 10.8%
Ingredients
10.1 lbs. (4.6 kg) light liquid malt extract
2 lbs. (907 g) U.K. roasted barley
1.25 lbs. (567 g) U.K. chocolate malt
0.75 lb. (340 g) U.K. black malt
2 lbs. (907 g) Belgian extra dark candi syrup (180 °L) (15 min.)
21 AAU Centennial hops (60 min.) (2 oz./57 g at 10.5% alpha acids)
13 AAU Chinook hops (15 min.) (1 oz./28 g at 13% alpha acids)
1 oz. (28 g) U.K. Golding hops (5 min.)
Wyeast 1028 (London Ale), White Labs WLP013 (London Ale), LalBrew Nottingham, or SafAle S-04 yeast
3⁄4 cup corn sugar (if priming)
Step by Step
Use 6.5 gallons (24.5 L) of water in the brew kettle; heat to 158 °F (70 °C).
Turn off the heat. Add the three crushed dark grains in a mesh bag and steep for 30 minutes. Remove and rinse grains gently.
Add the malt extract and stir thoroughly to dissolve completely. Turn the heat back on and bring to a boil.
Boil the wort for 60 minutes, adding hops at the times indicated. Add the candi syrup when 15 minutes remain in the boil.
Chill the wort to 64 °F (18 °C), pitch the yeast, and ferment until complete, allowing the temperature to rise as high as 70 °F (21 °C).
Rack the beer, prime and bottle condition, or keg and force carbonate.
Tips For Success:
Aging this beer for six months or more at cellar temperatures will allow the flavors to meld. If you plan to bulk age in a carboy, just make sure the beer is filled up above the curve of the neck and keep the airlock topped with sufficient liquid.
