Porter is a dark style of beer developed in London from well-hopped beers made from brown malt. The name was first recorded in the 18th century, and is thought to come from its popularity with street and river porters.
The history and development of stout and porter are intertwined. The name “stout” as used for a dark beer is believed to have come about because strong porters were marketed under such names as “Extra Porter”, “Double Porter”, and “Stout Porter”. The term “Stout Porter” would later be shortened to just “Stout”. For example, Guinness Extra Stout was originally called Extra Superior Porter and was only given the name Extra Stout in 1840.
18th and 19th century
In 1802 John Feltham wrote a version of the history of porter that has been used as the basis for most writings on the topic. Very little of Feltham’s story is backed up by contemporary evidence; his account is based on a letter written by Obadiah Poundage (who had worked for decades in the London brewing trade) in the 1760s. Feltham badly misinterpreted parts of the text, mainly due to his unfamiliarity with 18th-century brewing terminology. Feltham claimed that in 18th-century London a popular beverage called three threads was made consisting of a third of a pint each of ale, beer and twopenny (the strongest beer, costing two pence a quart). About 1730, Feltham said, a brewer called Harwood made a single beer called Entire or Entire butt, which recreated the flavour of “three threads” and became known as “porter”.
Porter is mentioned as early as 1721, but no writer before Feltham says it was made to replicate “three threads”. Instead, it seems to be a more-aged development of the brown beers already being made in London. Before 1700, London brewers sent out their beer very young and any ageing was either performed by the publican or a dealer. Porter was the first beer to be aged at the brewery and dispatched in a condition fit to be drunk immediately. It was the first beer that could be made on any large scale, and the London porter brewers, such as Whitbread, Truman, Parsons and Thrale, achieved great success financially.
Early London porters were strong beers by modern standards. Early trials with the hydrometer in the 1770s recorded porter as having an OG (original gravity) of 1.071 and 6.6% ABV. Increased taxation during the Napoleonic Wars pushed its gravity down to around 1.055, where it remained for the rest of the 19th century. The popularity of the style prompted brewers to produce porters in a wide variety of strengths. These started with Single Stout Porter at around 1.066, Double Stout Porter (such as Guinness) at 1.072, Triple Stout Porter at 1.078 and Imperial Stout Porter at 1.095 and more. As the 19th century progressed the porter suffix was gradually dropped.
The large London porter breweries pioneered many technological advances, such as the use of the thermometer (about 1760) and the hydrometer (1770). The use of the latter transformed the nature of porter. The first porters were brewed from 100% brown malt. Now brewers were able to accurately measure the yield of the malt they used, and noticed that brown malt, though cheaper than pale malt, only produced about two thirds as much fermentable material. When the malt tax was increased to help pay for the Napoleonic War, brewers had an incentive to use less malt. Their solution was to use a proportion of pale malt and add colouring to obtain the expected hue. When a law was passed in 1816 allowing only malt and hops to be used in the production of beer (a sort of British Reinheitsgebot), they were left in a quandary. Their problem was solved by Wheeler’s invention of the almost black patent malt in 1817. It was now possible to brew porter from 95% pale malt and 5% patent malt, though most London brewers continued to use some brown malt for flavour.
Until about 1800, all London porter was matured in large vats, often holding several hundred barrels, for between six and eighteen months before being racked into smaller casks to be delivered to pubs. It was discovered that it was unnecessary to age all porter. A small quantity of highly aged beer (18 months or more) mixed with fresh or “mild” porter produced a flavour similar to that of aged beer. It was a cheaper method of producing porter, as it required less beer to be stored for long periods. The normal blend was around two parts young beer to one part old.
After 1860, as the popularity of porter and the aged taste began to wane, porter was increasingly sold “mild”. In the final decades of the century, many breweries discontinued their porter, but continued to brew one or two stouts. Those that persisted with porter, brewed it weaker and with fewer hops. Between 1860 and 1914, the gravity dropped from 1.058 to 1.050 and the hopping rate from two pounds to one pound per 36-gallon barrel.
20th and 21st century
During the First World War in Britain, shortages of grain led to restrictions on the strength of beer. Less strict rules were applied in Ireland, allowing Irish brewers such as Guinness to continue to brew beers closer to pre-war strengths. English breweries continued to brew a range of bottled, and sometimes draught, stouts until the Second World War and beyond. They were considerably weaker than the pre-war versions (down from 1.055-1.060 to 1.040-1.042) and around the strength that porter had been in 1914. The drinking of porter, with its strength slot now occupied by single stout, steadily declined, and production ceased in the early 1950s.
A revival of the style began in 1978, when the Penrhos microbrewery introduced a porter. A little later, Timothy Taylor began to brew a porter as well. There are now dozens of breweries in Britain making porter, with Fuller’s London Porter winning gold and silver medals at the 1999, 2000 and 2002 International Beer & Cider Competitions, and CAMRA’s Supreme Champion Winter Beer of Britain silver medal in 2007, with Wickwar Brewery’s Station Porter winning gold in 2008.
Many breweries brew porters in wide varieties, including, but not limited to, pumpkin, honey, vanilla, plum, and chocolate. Specialised porter brews continue the tradition of aging in barrels, and the use of bourbon barrels is not uncommon.
Porter was first brewed in Ireland in 1776 and although Arthur Guinness did not start brewing until 1787 he had phased out all other types of beer from his Guinness Brewery by 1799. Beamish and Crawford in Cork and Murphy’s Brewery followed suit and abandoned ale in favour of porter. The move from porter to stout was made when Arthur Guinness realised that he would pay less tax if he used unmalted and roasted barley in his beer.
In Ireland, especially Dublin, the porter was known as “plain porter” or just “plain”. This is the drink referred to in Flann O’Brien’s poem “The Workman’s Friend”: “A pint of plain is your only man.” By contrast, extra-strong porter was called Stout Porter. The last Guinness Irish porter was produced in 1974, though the company launched a ‘revival’ based upon a 1796 recipe in 2014.
After the invention of malted barley roasted until black to impart a darker colour and distinct burnt taste to the beer in 1817, Irish brewers dropped the use of brown malt, using patent malt and pale malt only, while English brewers continued using some brown malt, giving a difference in style between English and Irish porters.
A version known as Baltic porter is brewed in Finland, Estonia, Latvia, Lithuania, Czech Republic, Poland, Russia, Ukraine, Denmark, Sweden and the United States. Baltic porter was introduced from Britain in the 18th century as a warm fermenting beer and remained so until the second half of the 19th century when many breweries began to brew their porter at cooler temperatures. In Germany, Baltic porter was brewed from the mid-19th century to German reunification. In 1990, all German porter producing breweries were in former East Germany, and none survived the transition to a market economy. The late 1990s saw to the re-launch of Baltic porters by several German breweries.
Porter was being commercially brewed in the United States in the 18th century, especially in New England and Pennsylvania. After the introduction of lagers in the United States in the 1850s, breweries began brewing their porters with lager yeast rather than a top-fermenting one. In addition, these American porters often included adjuncts such as maize, molasses, and Porterine. Porterine was developed in America as a brewer’s tool, added in the wort of lighter beers, to add colour and flavour which emulate that of a porter. Porterine is made from the slow cooking of corn syrup, which concentrates the sugars in the substance. With this concentration comes the caramel-like color and consistency of Porterine. With the advent of the craft brewing movement, many microbreweries produce porters and stouts with traditional methods as well as the American techniques.