In the next day or two, I'll have a look at the beers, but first, let's peruse the history of this style--certainly one of the three or four most important beers ever brewed.
History of the Style
The exact date of porter's birth and the nature of the infant are lost to history. There's quite a bit of evidence that the "three-threads" theory is a case of bad history repeated for 200 years. Rather, like most styles, it appears likely that there was no birth, no infant, no single moment of inception. Like most inventions, it was an evolutionary process--a common brown beer that came to be called porter as it was refined and improved.
In the early part of the 18th century (until 1740, according to Cornell), it bore a very strong resemblance to gratzer. Made entirely of smoky brown malt, it was heavily hopped and not exactly tasty, according to early reports. In order to reach palatability, that smoke needed to dissipate, and so starting around 1740, brewers began to age it in wooden vats--at least months and often as long as two years. This iteration bore strong resemblance to oud bruin, for, predictably, those vats inoculated it with wild yeasts and bacteria. At a certain point, brewers realized that the inefficient brown malt (which was cheap) wasn't the value they imagined. To achieve the dark color, they developed "patent" malt--charred black--which they used to stain a grist of mostly pale malts. This was effectively the beer we'd recognize, but it took 100 years to develop.
Blending was another important feature of porter consumption. Especially as the recipe evolved, consumers began to appreciate a little liveliness in their beer. Publicans would therefore mix aged, still beer with young, effervescent beer, producing a pour that had elements of both. In Amber, Black and Gold, Cornell writes:
"In the pub, the casks containing this highly conditioned beer were known as 'high,' while casks containing maturer, less lively beer were known as 'low.' Publicans would fill glasses three-quarters full from the 'low cask' and then top them up with foaming beer from the 'high cask.' The 'high' and 'low' casks system was in use for Irish stout and porter until at least the 1960s."
Success of the Style
Pilsners and their more insipid descendants have conquered the world more spectacularly than any style in history. Yet light lagers weren't the first--porter was. (Or porter and stout--but let's leave aside the distinction for this post.) Prior to the industrial revolution, beer was necessarily a local product. It just wasn't possible to produce it for wide distribution. But porter arrived just as industry was beginning. Within a hundred years, breweries would be producing massive amounts of the stuff and storing it in vats so large (20 feet high) they sometimes burst, sending floods down the streets of London.
It was first sent to Ireland, where it was wildly successful (so much so that for long decades, Ireland was the only real producer of black ales to be found in the US). The trade continued to spread, making it to the New World, Russia, the Baltic states and Scandinavia. It was so popular Germans imitated it, and brewers across the globe started brewing it. Later it spread to Africa and the Caribbean. Extant examples of porter and stout still exist from Russia, Poland, and Australia. Despite the waxing and waning of other styles, the arrival of new immigrants, and the crushing success of light lagers, black ales have continued to be an international commodity. A remarkable success by any standard.
Imperial stouts and Baltic porters are the quintessential dark ale exports--and among the most popular styles among beer geeks. Of course, modern American imperial stouts and Baltic porters look quite different from the original beers shipped to the Tsars. Tomorrow I'll reflect a bit more on this change when I review Widmer's W '11 KGB Stout, Full Sail's Black Gold, and Lompoc's Batch 69 Baltic Porter.