A Stout Companion
Originally published in BrewingTechniques 1 (4), November/December 1993.
The art of brewing this most extreme beer style is revealed by both old brewing texts and a discussion of the many worldwide variations on a dark and bitter theme.
Despite stout's international popularity, it is not a unified style but a family of substyles. Indeed, the range of variation within these black beers is astounding. Not only do stouts offer unparalleled levels of flavor intensity, but they also complement a wide array of foods from oysters to chocolate.
The origins of stout are even more obscure than those of porter, of which stout is probably an offshoot. Although stout is mentioned as early as the late 1600s, most likely it was a strong dark ale of the type now called "old." For centuries, the British used dark malts to balance the sweetness of the old-style unhopped ales and continued to use them after hops were generally adopted (ca. 1650). These were brown malts, used for all or a large proportion of the grist. Black malts were first introduced in the 1830s in the London porter industry, and chocolate malt and roasted barley followed later. Guinness, like many great brewers, first gained fame with porter. Stout seems to have really come into its own as porter entered its long decline.
The various substyles of stout represent a range of gravities and palates as great as any other family of ales. The unifying factors are the very dark, usually black color, and the more or less pronounced roasted, grainy palate. Beyond this, gravities range from 9 to 25 degrees P (SG 1.036 to >1.100), and bitterness ranges from as low as 20 to >60 IBU.
STOUTS BACK THEN
Wahl-Henius (1) provide good descriptions of stout production in the late 19th century. Single stouts were brewed to 16-18 degrees P (SG 1.065- 1.073), double stouts to 18-20 degrees P (SG 1.073-1.080), imperial stout to 20-25 degrees P (SG 1.080-1.100), and Russian export to >25 degrees P (SG >1.100) (1).
Stouts were aged "stock ales," typically with Brettanomyces secondary fermentation. One common method of achieving this character economically was the blending process called "vatting." A proportion of well-aged stout of >20 degrees P (SG 1.080) would be blended into a young "running" stout or porter of 12-13 degrees P (SG 1.049-1.053). This was thought to give better results in English brewing than could be obtained with a single unblended stout of 16-17 degrees P (SG 1.065-1.069) (1). Vatting was the rule in stout brewing and was used for other types of ales as well. It is still practiced by a number of stout brewers, including Guinness.
IRISH DRY STOUTS
Guinness is deservedly the most famous stout in the world, and for many it serves as the benchmark against which all others are measured. This is perhaps unfair to stouts whose origins and intentions are different from those of Guinness, but it is certainly both the prototype of the Irish style and the most popular stout in the world. Beamish and Murphy stouts are just as authentic as their famous countryman. A remarkably successful example of the style is Main Sail Stout from Full Sail Ales of Hood River, Oregon -- a very worthy stout indeed.
That said, Guinness is a schizophrenic beverage. The most casual drinker will notice the difference between the draught product (including the remarkable new draught in a can) and the bottle. The difference is primarily due to draught Guinness' unique combination of low carbonation and the practice of dispensing under a combination of nitrogen and carbon dioxide, which promotes the characteristic creamy head and smooth body. The gravity of bottled Guinness stout is higher -- about 13 degrees P (SG 1.052), compared with 10 degrees P (SG 1.040) for draught Guinness sold in the United States. Gravities in Britain and Ireland run lower: about 9 degrees P (SG 1.036) for draught and 11.5 degrees P (SG 1.046) for bottled, and slightly higher for both in winter. Alas, bottled Guinness in Britain is no longer bottle-conditioned.
The dry character of Irish stouts is far more pronounced in draught stout, which is a well-attenuated beer. Relative to draught stout, the higher gravity of the bottled beer gives it a sweeter, fuller palate, and the higher carbonation gives a rougher, more prickly mouthfeel. The draught has a definite "ironlike" note, and the acetic aroma sometimes encountered is due to poorly maintained draft systems. Liberal hopping rates emphasize the dryness of Irish stouts, though hops are used for bittering only, and hop aroma is not appropriate to this style. The bitterness is very clean and for most Guinness products roughly matches the last two numbers of the original SG; a bottled stout of specific gravity 1.052, for example, has about 50 IBU. Many details of Guinness's production remain closely guarded secrets. Most brewers know, however, that the use of very dark roasted barley, rather than black malt, is critical to the distinctive Irish palate, as is the inclusion of perhaps 10% of raw unmalted barley, cooked or flaked to gelatinize the starch. Pale malt composes the rest of the grist; no caramel or crystal malts are used. Vatting is used for all Guinness products.
English stouts are often thought of as sweet, at least relative to the Irish stouts. Although some English stouts are sweet indeed, the tendency is toward a more rounded and less intense palate than that found in Irish stouts. This tendency is evident in the occasional Scottish example as well. The "sweet stout" substyle is synonymous with "milk stout" -- a moderate-gravity stout, usually about 9.5-10.5 degrees P (SG 1.038-1.042), hopped at a fairly low rate, and usually sweetened by priming with unfermentable lactose. The soft, roasted character is usually from chocolate malt. Whitbread's Mackeson is to sweet stout as Guinness is to Irish -- the classic -- although England offers many other good examples. Export Mackeson is considerably higher in gravity, approximately 14 degrees P (SG 1.056), and has a more aggressive "stouty" palate and a much less pronounced sweetness.
Other English stouts occupy a middle ground between the sweet and dry styles, and much variation in palate and balance occurs between brewers. Some English stouts are quite intense. Black and/or chocolate malts plus crystal malts are the usual color malts. Up to 10% flaked maize may be used in the grist; British brewers swear that maize improves head retention. Also typically British is the use of dark brewing sugars such as black treacle (blackstrap molasses), either in the kettle, as a primer, or both. The term "cream" stout may once have been a market variation on milk stout but now usually means that the stout is not in the Irish dry style. Cream stout is reasonably descriptive of the palate of English-style stouts.
Oatmeal stout has become an important substyle for American microbreweries, probably because of the influence of Michael Jackson's writings (2). Originally an English style and once extinct, Samuel Smith1s of Yorkshire now produces an excellent revivalist version. A number of U.S. microbreweries are brewing excellent oatmeal stouts, among them the superlative Barney Flats by Anderson Valley Brewing (Boonville, California) and one from Breckenbridge Brewing (Breckenbridge, Colorado). Modern oatmeal stouts range from about 12 to 15 degrees P (SG 1.048-1.060) and typically have a heavily roasted palate supported by caramel malts and fairly high bitterness levels.
Oats are even harder to work with than flaked barley or wheat malt. In addition to a high protein and lipid content, oats are very rich in beta-glucan gums (for evidence, you need look no further than the consistency of your breakfast porridge). Most brewers find it impossible to lauter with more than 5-7% oats in the grist. More might be practical if a beta-glucanase rest is incorporated in the mash program; in my experience, however, 5% is practical with single-temperature infusion mash equipment and gives the distinctive silkiness that is the hallmark of oatmeal stout.
Use the most heavily processed oats you can get. Ordinary "quick" oats from the grocery store work well, but the "instant" type is better. Instant-type oats are much more thoroughly gelatinized than regular oatmeal and are used by some commercial brewers. Avoid steel-cut oats unless you are prepared to cook them before mashing. The rule of thumb: The shorter the recommended cooking time, the more suitable for brewing. The same applies to flaked barley, although 10% can be used comfortably. In both cases I recommend using an iodine test for conversion, although the results can be hard to read in a stout mash. As for lautering, follow the guidelines given in a previous "Brewing in Styles" installment on American wheat beers (3). The delightful texture of oatmeal stout is best expressed in the unfiltered form, which is just as well because filtration is usually very difficult.
As described in the last issue, stouts and porters were the basis of an important export trade from England and later from Ireland, first to the Baltic region and then to the tropics. In addition to the remarkable Baltic brews, the legacy of stout consumption and brewing stretches to Africa, Southeast Asia, the Indo-Pacific region, the Caribbean, and possibly South America (Xingu seems more stout than schwarzbier to me).
The grandfather and dean of them all is the incomparable Courage Russian Imperial Stout, brewed to a gravity of 26 degrees P (SG 1.104) and capable of lasting 25 years or more in the bottle. It is the beer world's answer to a vintage Cockburn port. Jackson likens the palate to that of a British Christmas pudding (2), but that hardly conveys the layer of complexity and intensity found within the nip bottle. Any descriptions of the harmonious melange of honey, tar, currants, caramel, roasted malts, and dozens of esters and aldehydes, underpinned by generous hopping, is grossly inadequate. Unfortunately, Courage is impossible to find outside Britain and is even very scarce within. Since Courage closed its London brewery in 1982, it has been brewed only sporadically at various locations. I must continue to refuse all offers for my bottles of the 1982.
The export categories of double, triple, and Russian once offered many representatives, but today their numbers have dwindled. There have been revivals, most notably Samuel Smith's Imperial Stout (Yorkshire, England) and Grant's Imperial Stout of (Yakima, Washington). These are both fine beers, but with gravities at about 18 degrees P (SG 1.072), they barely qualify as double stout and pale next to the Courage original. One notable holdover, though, is Guinness Foreign Extra Stout, known as "FES" to the brewers. FES is everything you would expect from bottled Guinness, with a gravity of 18-19 degrees P (SG 1.072-76) and tremendous flavor density. It is widely available in the Caribbean, West Africa, and places like Singapore and Hong Kong, but, sadly, not in North America. Where it is available, it is far more than just beer. It is universally regarded as a tonic and aphrodisiac. One slogan is "Guinness puts it back." Like its Baltic trade forerunners, Guinness FES has spawned not only license brewing arrangements but numerous emulators around the tropics, from the pedestrian Red Dragon of Desnoes-Geddes, Jamaica, to the excellent bottle-conditioned ABC Stout of Malaysia. Australian and New Zealand stouts are descended from English forebears and are not in the export style.
Although some ale breweries in the Eastern United States brewed stout before Prohibition, it seems that it was not brewed after 1919. The first revival American stout was, quite naturally, brewed by the nation's first microbrewery, New Albion of Sonoma, California, around 1978. Virtually all other ale microbreweries followed suit, starting with Boulder and Sierra Nevada in the early 1980s. Stouts have since become a major part of the microbrewer's repertoire, and it is uncommon for brewpubs or microbreweries not to brew at least one seasonally. They are a frequent choice for special Christmas beers, a practice followed by Boulder Brewing for a number of years. Although I describe only a few American stouts here, there are many other outstanding labels. Perhaps one reason for stout's popularity with home brewers and microbrewers is their forgiving nature: the intense flavors can conceal a multitude of small brewing mistakes.
Typical modern American stouts range between 11 and 18 degrees P (SG 1.044-1.072). I know of no American stout brewed to true Russian imperial gravity, though this may change. Home brewers like to take this style to extremes, both in gravity and odd grist constituents, including licorice and even coffee or chocolate. Many microbrewers attempt to emulate Guinness, but few succeed at the difficult task of achieving a true Irish palate. Many others are broadly in the English style, sweeter and fuller of palate. So far, it is not really possible to speak of an American-style stout; those with a lot of hop aroma are largely confined to the West Coast micros and are not universal even there.
Stout developed in association with the carbonate water of London and Dublin. The acidity of the roasted grains balances alkaline mash and sparge water. When brewing with soft or slightly sulfate waters, I recommend adding calcium carbonate to the mash (not to the water) to bring the pH up to the optimal 5.2-5.4 range. Those with high-sulfate or very hard water will have to resort to another water source or to reverse-osmosis or deionization equipment.
Bitterness ranges from 30 to >60 IBU. Many brewers, especially on the West Coast, use aroma hops rather liberally, an acceptable practice for American stouts, according to Wahl and Henius. Dry hopping is never appropriate. "Coarse" high-alpha hops are highly acceptable; noble aroma hops would essentially be wasted. The high cohumulone content of many new high-alpha hops, however, suggests that a blend with a lower alpha hop such as the traditional Fuggles or Willamette would be best for a clean bitterness. Recommended varieties for stout include Cluster, Northern Brewer, and Bullion or Brewer's Gold.
Stouts have been fermented with good results by virtually every ale yeast available. Most brewers use their house ale yeast. When brewing in the Irish style I particularly recommend Wyeast #1084 Irish Ale Yeast. It is the house yeast at Full Sail Ale, and the resulting Main Sail Stout speaks for itself. This yeast is moderate in both attenuation and flocculation and is especially well suited to life in unitank fermentors.
a) Classic Irish-Style Dry Stout
Dry stouts have an initial malt and caramel flavor profile with a distinctive dry-roasted bitterness in the finish. Dry stouts achieve a dry-roasted character through the use of roasted barley. Some slight acidity may be perceived but is not necessary. Hop aroma and flavor should not be perceived. Dry stouts have a light to medium body. Fruity esters are minimal and overshadowed by notable hop bitterness and roasted barley character. Diacetyl (butterscotch) should be very low or not perceived. Head retention and rich character should be part of its visual character.
SG 1.038-48 (9.5-12.0)1.008-14 (2-4); IBUs 30-40
b) Foreign-Style Stout
Foreign-style stouts have an initial malt sweetness and caramel flavor with a distinctive dry-roasted bitterness in the finish. Some slight acidity is permissible, and a medium- to full-bodied mouthfeel is appropriate. Hop aroma and flavor should not be perceived. The perception of fruity esters is low. Diacetyl (butterscotch) should be negligible or not perceived. Head retention is excellent.
SG 1.052-72 (13.0-18.0)1.008-20 ; IBUs 30-60
c) Sweet Stout
Sweet stouts, also referred to as cream stouts, have less roasted bitter flavor and more full-bodied mouthfeel than dry stouts. The style can be given more body with milk sugar (lactose) before bottling. Malt sweetness, chocolate and caramel flavor should dominate the flavor profile. Hops should balance sweetness without contributing apparent flavor or aroma.
SG - 1.045-56 (11.3-14.0)1.012-20 (3-5); Ibus -15-25
d) Oatmeal Stout
Oatmeal stouts typically include oatmeal in their grist, resulting in a pleasant, full flavor and smooth profile that is rich without being grainy. Roasted malt character of caramel and chocolate should be evident, smooth and not bitter. Bitterness is moderatenot high. Hop flavor and aroma are optional but should not overpower the overall balance. This is a medium- to full-bodied beer with minimal fruity esters.
SG - 1.038-56 (9.5-14.0)1.008-20 (2-5); IBUs - 20-40
e) Imperial Stout
Dark copper to very black, imperial stouts typically have alcohol contents exceeding eight percent. The extremely rich malty flavor and aroma are balanced with assertive hopping and fruity-ester characteristics. Perceived bitterness can be moderate, balanced with malt character, to very high in the darker versions. Roasted malt astringency and bitterness can be perceived moderately but should not overwhelm the overall character. Hop aroma can be subtle to
overwhelmingly floral. Diacetyl (butterscotch) levels should be very low.
SG - 1.075-90 (18.8-22.5)1.020-30 (5-8); IBUs = 50-80