Ask a range of people what the difference is between porters and stouts and you might get as many answers as the number of people you ask. Conducting a blind tasting might be just as unproductive as the styles tend to overlap considerably.
To try to figure out what the difference is—if there even is one—I sat down with Sean Hoyne who has been brewing beer professionally in Victoria since 1989 and has considered himself a student of beer history for even longer than that. Fittingly, I sipped from a glass of Hoyne’s Finnegans Irish Stout while we chatted.
In order to understand porter and stout, Hoyne said we have to look at the way beer evolved in Britain. The earliest ales were brown beers made from malted barley that was lightly roasted over hardwood fires. This resulted in a brownish malt that was very inconsistent in quality. It was slightly smoky and some of the kernels would have torrified (popped like popcorn), adding a burnt-caramelized flavour.
Brewers generally made two styles.
“Mild beer was fresh beer: beer that hadn’t been aged,” Hoyne explained, while brown beer would typically sit in a vat anywhere from four months to a year, during which it would become dry and acidified from bacteria in the vat. “They called it ‘stale beer,’ but not in a negative connotation. ‘Stale’ just meant it had been kept longer.” Apparently, a certain sourness was a desired flavour.
The myth of porter’s birth (according to the Oxford Companion of Beer) states that in 1722, a brewer named Ralph Harwood decided to create a special blended beer for “a publican who ran the Blue Last, a working-class watering hole on Shoreditch’s Great Eastern Street.” The pub was frequented mostly by so-called porters, strong men whose job was to carry goods unloaded from ships at the docks to markets, shops and warehouses in the heart of London. The new beer was a hit and came to be named after the porters who loved it.
Beer historians have largely debunked this origin story, arguing that porter wasn’t created in one day, but rather evolved as the population of London swelled and new technological advancements allowed for breweries to grow larger and larger. Porter was certainly a blended style at first, but as it grew in popularity, breweries came to brew it in a single batch as they would with any other beer.
Some of these porter breweries built enormous aging vats that would dwarf even the biggest fermentation tanks used today. The largest on record held about 32,500 hL (over three million litres). To put that in context, Hoyne believes the biggest in the world currently is a 1,500-barrel (1,760 hL) vessel at Coors in Colorado.
The giant porter vats built in the early 1800s were so big that breweries held promotional dinner parties for dozens of people inside them when they were empty. Sadly, in October 1814, a full tank burst, resulting in a flood of porter that killed eight people.
Porter took England by storm in the 18th century and well into the 19th century. One of the many brewers who made it was Arthur Guinness in Dublin, which finally brings us to stout. Guinness made a strong version called stout porter, but Hoyne pointed out that “all that ‘stout’ referred to was the gravity of the beer: if it was ‘stout’ it was considered a stronger beer.” And at this point both versions were still brown beers, not black.
Two technological advances helped to change that. One was the brewer’s hydrometer, which arrived on the scene in the late 1700s. Prior to that, brewers could only guess at the efficiency of the malts they used, with the results varying considerably from batch to batch. Hoyne explained that using a hydrometer showed brewers that they could get much better extract out of pale malt than from the brown malt they mainly used.
Then in 1817, Daniel Wheeler patented a new process of roasting barley in a metal cylinder similar to a coffee roaster. The result was black patent malt, and brewers could use it to give porter a dark colour and roasted flavour without having to use as much brown malt—instead relying on the more efficient pale malt to make up the majority of the grain bill.
Porters and “stout porters” gradually got darker in colour. Eventually, with the advent of pale styles like IPAs and pilsners in the late 1800s, porters and stouts faded away in popularity. In the early 20th century, British beers became dominated by lower alcohol styles like milds and bitters, and porters disappeared almost entirely. At some point, Guinness dropped the “porter” part of the name and kept making a stout, but paradoxically with a lower alcohol content, and this became the standard to which all stouts were compared.
Whether today’s stouts and porters resemble the original versions from 200 years ago is doubtful, but who cares? Find your favourite version of each and there you have the perfect example of the style—for you.
What’s the diff?
According to the Beer Judge Certification Program (BJCP) Style Guidelines, porter is “a moderate-strength brown beer with a restrained roasty character and bitterness. May have a range of roasted flavours, generally without burnt qualities, and often has a chocolate-caramel-malty profile.” Meanwhile, Irish Stout is described as “a black beer with a pronounced roasted flavour, often similar to coffee.” To confuse matters, however, there are other categories for Baltic porter, sweet stout, oatmeal stout, foreign extra stout, and tropical stout, as well as a whole separate section for American porter and stout.
Driftwood Brewing Blackstone Porter
Hoyne Brewing Finnegans Irish Stout
Nelson Brewing Blackheart Oatmeal Stout
Persephone Brewing Dry Irish Stout
Townsite Brewing Perfect Storm Stout
Yellow Dog Brewing Shake A Paw Smoked Porter
East Van Brewing’s When It Rains It Porters