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.
Porter is mentioned as early as 1721 and was 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. The large London porter breweries pioneered many technological advances, such as the use of the thermometer (about 1760) and the hydrometer (1770).
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.
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.
Brown Porter
History: Originating in England, porter evolved from a blend of beers or gyles known as “Entire.” A precursor to stout. Said to have been favored by porters and other physical laborers.
Aroma: Malt aroma with mild roastiness should be evident, and may have a chocolaty quality. May also show some non-roasted malt character in support (caramelly, grainy, bready, nutty, toffee-like and/or sweet). English hop aroma moderate to none. Fruity esters moderate to none. Diacetyl low to none.
Appearance: Light brown to dark brown in color, often with ruby highlights when held up to light. Good clarity, although may approach being opaque. Moderate off-white to light tan head with good to fair retention.
Flavor: Malt flavor includes a mild to moderate roastiness (frequently with a chocolate character) and often a significant caramel, nutty, and/or toffee character. May have other secondary flavors such as coffee, licorice, biscuits or toast in support. Should not have a significant black malt character (acrid, burnt, or harsh roasted flavors), although small amounts may contribute a bitter chocolate complexity. English hop flavor moderate to none. Medium-low to medium hop bitterness will vary the balance from slightly malty to slightly bitter. Usually fairly well attenuated, although somewhat sweet versions exist. Diacetyl should be moderately low to none. Moderate to low fruity esters.
Mouthfeel: Medium-light to medium body. Moderately low to moderately high carbonation.
Overall Impression: A fairly substantial English dark ale with restrained roasty characteristics.
Comments: Differs from a robust porter in that it usually has softer, sweeter and more caramelly flavors, lower gravities, and usually less alcohol. More substance and roast than a brown ale. Higher in gravity than a dark mild. Some versions are fermented with lager yeast. Balance tends toward malt more than hops. Usually has an “English” character. Historical versions with Brettanomyces, sourness, or smokiness should be entered in the Specialty Beer category (23).
Ingredients: English ingredients are most common. May contain several malts, including chocolate and/or other dark roasted malts and caramel-type malts. Historical versions would use a significant amount of brown malt. Usually does not contain large amounts of black patent malt or roasted barley. English hops are most common, but are usually subdued. London or Dublin-type water (moderate carbonate hardness) is traditional. English or Irish ale yeast, or occasionally lager yeast, is used. May contain a moderate amount of adjuncts (sugars, maize, molasses, treacle, etc.).
Commercial Examples: Fuller's London Porter, Samuel Smith Taddy Porter, Burton Bridge Burton Porter, RCH Old Slug Porter, Nethergate Old Growler Porter, Hambleton Nightmare Porter, Harvey’s Tom Paine Original Old Porter, Salopian Entire Butt English Porter, St. Peters Old-Style Porter, Shepherd Neame Original Porter, Flag Porter, Wasatch Polygamy Porter
Robust Porter
History: Stronger, hoppier and/or roastier version of porter designed as either a historical throwback or an American interpretation of the style. Traditional versions will have a more subtle hop character (often English), while modern versions may be considerably more aggressive. Both types are equally valid.
Aroma: Roasty aroma (often with a lightly burnt, black malt character) should be noticeable and may be moderately strong. Optionally may also show some additional malt character in support (grainy, bready, toffee-like, caramelly, chocolate, coffee, rich, and/or sweet). Hop aroma low to high (US or UK varieties). Some American versions may be dry-hopped. Fruity esters are moderate to none. Diacetyl low to none.
Appearance: Medium brown to very dark brown, often with ruby- or garnet-like highlights. Can approach black in color. Clarity may be difficult to discern in such a dark beer, but when not opaque will be clear (particularly when held up to the light). Full, tan-colored head with moderately good head retention.
Flavor: Moderately strong malt flavor usually features a lightly burnt, black malt character (and sometimes chocolate and/or coffee flavors) with a bit of roasty dryness in the finish. Overall flavor may finish from dry to medium-sweet, depending on grist composition, hop bittering level, and attenuation. May have a sharp character from dark roasted grains, although should not be overly acrid, burnt or harsh. Medium to high bitterness, which can be accentuated by the roasted malt. Hop flavor can vary from low to moderately high (US or UK varieties, typically), and balances the roasted malt flavors. Diacetyl low to none. Fruity esters moderate to none.
Mouthfeel: Medium to medium-full body. Moderately low to moderately high carbonation. Stronger versions may have a slight alcohol warmth. May have a slight astringency from roasted grains, although this character should not be strong.
Overall Impression: A substantial, malty dark ale with a complex and flavorful roasty character.
Comments: Although a rather broad style open to brewer interpretation, it may be distinguished from Stout as lacking a strong roasted barley character. It differs from a brown porter in that a black patent or roasted grain character is usually present, and it can be stronger in alcohol. Roast intensity and malt flavors can also vary significantly. May or may not have a strong hop character, and may or may not have significant fermentation by-products; thus may seem to have an “American” or “English” character.
Ingredients: May contain several malts, prominently dark roasted malts and grains, which often include black patent malt (chocolate malt and/or roasted barley may also be used in some versions). Hops are used for bittering, flavor and/or aroma, and are frequently UK or US varieties. Water with moderate to high carbonate hardness is typical. Ale yeast can either be clean US versions or characterful English varieties.
Commercial Examples: Great Lakes Edmund Fitzgerald Porter, Meantime London Porter, Anchor Porter, Smuttynose Robust Porter, Sierra Nevada Porter, Deschutes Black Butte Porter, Boulevard Bully! Porter, Rogue Mocha Porter, Avery New World Porter, Bell’s Porter, Great Divide Saint Bridget’s Porter
Baltic Porter
History: Traditional beer from countries bordering the Baltic Sea. Derived from English porters but influenced by Russian Imperial Stouts.
Aroma: Rich malty sweetness often containing caramel, toffee, nutty to deep toast, and/or licorice notes. Complex alcohol and ester profile of moderate strength, and reminiscent of plums, prunes, raisins, cherries or currants, occasionally with a vinous Port-like quality. Some darker malt character that is deep chocolate, coffee or molasses but never burnt. No hops. No sourness. Very smooth.
Appearance: Dark reddish copper to opaque dark brown (not black). Thick, persistent tan-colored head. Clear, although darker versions can be opaque.
Flavor: As with aroma, has a rich malty sweetness with a complex blend of deep malt, dried fruit esters, and alcohol. Has a prominent yet smooth schwarzbier-like roasted flavor that stops short of burnt. Mouth-filling and very smooth. Clean lager character; no diacetyl. Starts sweet but darker malt flavors quickly dominates and persists through finish. Just a touch dry with a hint of roast coffee or licorice in the finish. Malt can have a caramel, toffee, nutty, molasses and/or licorice complexity. Light hints of black currant and dark fruits. Medium-low to medium bitterness from malt and hops, just to provide balance. Hop flavor from slightly spicy hops (Lublin or Saaz types) ranges from none to medium-low.
Mouthfeel: Generally quite full-bodied and smooth, with a well-aged alcohol warmth (although the rarer lower gravity Carnegie-style versions will have a medium body and less warmth). Medium to medium-high carbonation, making it seem even more mouth-filling. Not heavy on the tongue due to carbonation level. Most versions are in the 7-8.5% ABV range.
Overall Impression: A Baltic Porter often has the malt flavors reminiscent of an English brown porter and the restrained roast of a schwarzbier, but with a higher OG and alcohol content than either. Very complex, with multi-layered flavors.
Comments: May also be described as an Imperial Porter, although heavily roasted or hopped versions should be entered as either Imperial Stouts (13F) or Specialty Beers (23).
Ingredients: Generally lager yeast (cold fermented if using ale yeast). Debittered chocolate or black malt. Munich or Vienna base malt. Continental hops. May contain crystal malts and/or adjuncts. Brown or amber malt common in historical recipes.
Commercial Examples: Sinebrychoff Porter (Finland), Okocim Porter (Poland), Zywiec Porter (Poland), Baltika #6 Porter (Russia), Carnegie Stark Porter (Sweden), Aldaris Porteris (Latvia), Utenos Porter (Lithuania), Stepan Razin Porter (Russia), Nøgne ø porter (Norway), Neuzeller Kloster-Bräu Neuzeller Porter (Germany), Southampton Imperial Baltic Porter
Source: BJCP: http://www.bjcp.org/2008styles/style12.php, Wikipedia: https://en.wikipedia.org/wiki/Porter_(beer)