Porter is said to have been popular with transportation workers of Central London, hence the name. Most traditional British brewing documentation from the 1700s state that Porter was a blend of three different styles: an old ale (stale or soured), a new ale (brown or pale ale) and a weak one (mild ale), with various combinations of blending and staleness. The end result was also commonly known as "Entire Butt" or "Three Threads" and had a pleasing taste of neither new nor old. It was the first truly engineered beer, catering to the public's taste, playing a critical role in quenching the thirst of the UKs Industrial Revolution and lending an arm in building the mega-breweries of today.
Porter saw a comeback during the homebrewing and micro-brewery revolution of the late 1970s and early 80s, in the US. Modern-day Porters are typically brewed using a pale malt base with the addition of black malt, crystal, chocolate or smoked brown malt. The addition of roasted malt is uncommon, but used occasionally. Some brewers will also age their beers after inoculation with live bacteria to create an authentic taste. Hop bitterness is moderate on the whole and color ranges from brown to black. Overall they remain very complex and interesting beers.