Porters: Then and Nowby Roger Bergen
Republished from BrewingTecniques' 'Brewing in Styles' column, September/October 1993.
Porter is a notoriously obscure and enigmatic style. Its current revival in Britain and America invites us to shed some light on its 19th and 20th century origins with the aid of period sources.
DINOSAUR BEEROne of the pleasures of travel is stumbling across interesting and unique beers in odd parts of the world. I was fortunate enough to have such a serendipitous encounter a few years ago in the West Indies. I had recently arrived in St. Thomas to build a microbrewery. One day while pursuing a wharf-side liquor emporium in search of beer and the local rum ($1.69 a fifth), I stumbled across nothing less than a treasure trove of living fossils.
I was delighted to find that in the West Indies, stout is big, both figuratively and literally (the formidable Guinness Foreign Extra sells very well with the locals). As an aficionado of stout and a porter fanatic, I was close to heaven. In addition to the high-test Guinness, I found a lovely Tennantıs Cream Stout and the familiar Red Dragon Stout. I also found two Danish stouts: Carlsberg Imperial Stout/Gammel Porter and Ceres Stout, from a regional brewery in Jutland.
Carlsberg stout is a big beer, creamy and with tremendous balance and finesse, a worthy product even if it is bottom-fermented. It also testifies to the widespread lack of differentiation of stout and porter -- both "Imperial Stout" and "Gammel [old] Porter" are printed on the label. But the Ceres Stout was the real find. Its "horsey" nose immediately gave it away as a true old-fashioned stock ale in the British style. I have encountered only one other such beer: Strong Suffolk Ale, by Greene King of England, another fossil beer that is evidence of a brewer's dedication to keeping old traditions alive (1). (Note that Flanders zuur beer derives its acidity from Lactobacillus, whereas Strong Suffolk Ale definitely has the character of, and derives its acidity from, Brettanomyces.) Michael Jackson states that Ceres Stout is also labeled Gammel Jysk Porter (Old Jutland Porter) (2).
The Baltic stout and porter tradition derives from Britain's tremendous export trade in the 18th and 19th centuries, of which the best-known survivor is the superlative Courage Russian Stout. This "export porter/ imperial stout" style took root among the breweries of Denmark, Finland, and the Baltic states. Today, most Baltic porters and stouts are bottom-fermented, like Carlsberg Stout (from Denmark) and Koff Stout from Finland.
I cannot state definitely whether Ceres Stout is top-fermented, but it is clearly made using a Brettanomyces secondary fermentation. The resulting character is, uh, highly distinctive (wild "Bret" infection is often described as smelling like horse sweat). As with many of the odder Belgian ales, this apparent infection is actually the deliberate signature of a style. Today most brewers and drinkers definitely try to avoid "Bret" character, yet it was once the hallmark of an important branch of ale brewing. Ceres Stout/Gammel Jysk Porter is from a highly regarded, well-run modern brewery and is the result of careful attention to an almost extinct brewing practice: Hats off to Ceres. Beechwood chips seem like small potatoes compared to playing with a Brettanomyces culture in a lager brewery.
In all probability, porter had long existed in two versions: a mild running beer (perhaps blended with a portion of vatted porter) and a stock ale. As others have theorized, the strong "stock porters" may have sometimes been known as stout porter in the 1700s. Certainly, as we have seen, confusion exists to this day in the Baltic countries. In England, Samuel Smithıs Brewery of Yorkshire brews a Nourishing Stout that is sold in the United States as Taddy Porter; it has a heavy enough body for a stout. Clearly, drawing a firm and fast line between porter and stout is often difficult and has been for a long time. In Britain and America, as public taste shifted toward the more modern-style running ales, porter became a mild beer, as we can see from period sources.
The Wahl-Henius American Handy Book of the Brewing, Malting, and Auxiliary Trades of 1908 is one of the best references that can be found for old brewing practices (3). It contains numerous references to porter and an interesting section on British ale brewing, mostly cribbed from English brewing books. The book gives extensive descriptions of the then-current state-of-the-art ale brewing in Britain and the United States.
A table of gravities and hopping rates for English beers gives some interesting insights (4). London pale bitter ale has a quoted gravity of 14 Balling (SG 1.057) and a hopping rate of 11/2-2 lb/U.S. barrel; London four ale (mild), 13-14 Balling (SG 1.053-1.057) and 4/5-11/4 lb hops/barrel; and porter, 13-15 Balling (SG 1.053-1.061) and 4/5-11/2 lb hops/barrel. (Bear in mind that these were low alpha hops stored without refrigeration.) For porter and stout, all hops were added at the beginning of the boil, whereas for pale beers, 1/3-1/4 of the total was added 15-20 min before kettle knock-out. Clearly, porter in England was well on the way toward eventual merger with dark mild ale, although at that time Britain's excise tax system had not yet caused the general lowering of original gravities that it would later. Stock porters were apparently no longer brewed by this time, and English brewing practice clearly differentiated between porter and stout.
A section on British malting in Wahl-Henius book contains the following interesting note (5):
By World War II, porter was no longer produced in Britain. Irish porter technically died when Guinness stopped production in 1974. Curiously, as Michael Jackson relates, it had for some time been made with draught stout and a special blending beer in the pub, thus returning full circle to its 18th century origin (see Foster for discussion of "entire"). Murphy and in particular Beamish stouts may indeed be survivors under a different name, and the black-and-tan may be an approximation of Irish porter. Yet porter refused to die; the strong Baltic versions continued on, and a few porters survived in North America: Yuengling and (until relatively recently) Narragansett porters in the United States and Molson and Labatt's Dow Cream porters in Canada. Yuengling Porter is notably pale and has some corn adjunct and is bottom-fermented. The Canadian big-brewery porters are soft and creamy, with a tendency to sweetness; they are also hard to find.
Of course, thanks to the microbrewery movement in the United States porter has been revived as a major ale style, and a major porter revival under way in Britain signifies porter as the new frontier in the real ale scene. What can be said about the state of the style?
PORTERS TODAYModern U.S. microbrewery porters range from 10 to 18 degrees P (SG 1.040- 1.073). Most hover around 12-12.5 degrees P (SG 1.049-1.051). Bitterness can be from 20 to 45 IBU. One of the nontraditional features of many new American porters is hop aroma; a few are even dry-hopped. Note, however, that the Wahl-Henius book reports some late-hop aroma in American porters of 1908. Today many brewers tend to use the ubiquitous Cascade hop -- whose bright geraniol aroma is not always appropriate to dark beers -- rather than more traditional varieties like Fuggle/Willamette.
The grist bill is almost invariably based on a blend of pale lager malts with caramel and roasted malts. Most brewers seem to prefer the softer flavors of chocolate malt. Black malt, however, is used by a number of well-respected porter brewers, including Sierra Nevada and Anchor, and this is traditional and appropriate if done with some restraint so that its sharp, acrid character is subdued. Roasted barley can be very nice in porter, especially if an Irish style is desired. Some brewers use a blend of two or all three of these malts. Color can range from dark reddish-brown to black, but porter should be paler and more translucent than stout, especially if both are in the brewer's portfolio.
As with most dark beers, moderately carbonate water is traditional. London and Dublin both have carbonate water and are famous for their dark beers. Of course, modern water treatment techniques allow brewers to adjust virtually any water to a desired profile. Sulfates are less of a problem with porter than with stout because of the lower hopping rate. Chloride ions contribute palate fullness and are desirable in porter, helping to smooth out rough edges; either sodium or calcium chloride may be used.
Virtually any good ale yeast is acceptable. Naturally, an English or Irish yeast is appropriate when emulating the styles of those countries. Excessive fruitiness should perhaps be avoided in everyday-gravity porters but may be desirable in high-gravity versions. Attempting a stock porter with Brettanomyces secondary fermentation is the domain of only very brave souls. Brettanomyces cultures are available from UC Davis.
On the whole, porters should be fairly well attenuated -- quite dry in the case of Irish porters. Sweet porters may be considered a legitimate variation on the style, in deference to porter's close relationship to dark mild ale. A few micro and pub porters are very sweet indeed and might more appropriately be considered cream or sweet stouts. Modern porters are often both full of character and highly drinkable, and several of the best are highly representative of the mainstream of porter tradition but are world-class beers in their own right. Unfortunately, these relatively gentle beers can sometimes be overlooked in the black-beer lover's quest for intense flavor.
British revival porters, as is true of modern British beers in general, tend to be lower in gravity than their American counterparts and therefore perhaps a bit less authentic; 9.5-10.5 degrees P (SG 1.038-1.042) is typical. The palate tends to be soft and rounded. Mild ale malt is the most traditional for the base malt, with the addition variously of crystal, brown, and chocolate or black malt. Hopping rates, at least for the London and Burton porters I have tasted, are lower (in the range of 18-25 IBU) but higher than in mild ale. A single addition at the beginning of the boil seems to be standard. British brewers often use a small amount (less than 10%) of flaked maize in the mash tun, and glucose or invert sugar in the range of 10-20% in the kettle is common. London porters in particular often feature dark brewing sugars such as black treacle (blackstrap molasses) in the kettle and/or as primings in the cask. These sugars contribute unique flavors and aromas and deserve to be used more widely by American brewers.
AN ELUSIVE STYLEPorter has gone from virtual extinction to a new popularity, thanks to the microbrewery movement. Porter may also be the slipperiest style of all to grasp and define. While this quality of elusiveness inspires many brewers to seek the "perfect" porter, it is to our advantage that there can be many perfect porters!
REFERENCES(1) Michael Jackson, World Guide to Beer (AP Publishing, Lane Cove, Australia, 1977), p. 172.
(2) Ibid., p. 94.
(3) R. Wahl and M. Henius, American Handy Book of the Brewing, Malting, and Auxiliary Trades, vol. II (Wahl-Henius Institute, Chicago, 1908).
(4) Ibid., p. 1253.
(5) Ibid., pp. 900-901.
(6) Ibid., p. 1100.
(7) Ibid., p. 1275.
FURTHER READINGEckhardt, F., Essentials of Beer Style (Fred Eckhardt Associates, Portland, Oregon, 1989).
Foster, T., Porter (Brewers Publications, Boulder, Colorado, 1990).
Jackson, M., New World Guide to Beer (Running Press, Philadelphia, 1988).