Difference between porter and stout

Porter and stout have both been around for centuries. But their co-existence has shifted, weaving in and out of each other’s histories, sometimes overlapping, other times with one or the other more popular, and they’ve certainly not always tasted the way they taste today.

Stout and its dark, roasted counterpart, porter is similar in many ways. Their entwined history means they share a lot of similarities but also have some differences. 

They are both dark beers with quite broad flavour profiles however the flavour is what sets them apart. Porters are known for the notes of caramel, chocolate, cappuccino or liquorice. Porters range from dark copper to dark brown and may have flavours of toasted fruit. Porters are full of flavour, slightly sweet with an extra malt body. Stouts are known for their more coffee forward flavour and balanced bitterness.

It’s often said that porter came first, but that’s not true. Not technically, anyway. And porter as we know it today has a far more recent identity compared to the beers which were made famous in London a few hundred years ago. But let’s go back to the early 1700s and try to track it from the beginning.

From Brown to Porter

Porter is a beer wrapped in myth and anecdote. It begins with brown beer in the early 18th century London. Brown was the standard beer of the day and you could go into a pub and order ‘Mild’ or ‘Stale’ versions of that same brown beer; the stale was an older version of the younger, sweeter brown. Brewers delivered the beers to pubs soon after primary fermentation was done and the pub matured the beers themselves. 

Other beers were also available, including Amber, a variety of Ales, and Stout. The ales were less-hopped than the beers (the old differentiation of hop-less ales and hopped beer was beginning to change by this point), while Stout could’ve been any type of beer or ale and its name referred to it being a stronger ‘stouter’ version. It was supposedly common for a drinker to have a preferred mix of different beers poured into one tankard.

By the mid-1700s, as the industrial revolution reached brewing, those brown beers matured into porter, with the shift effectively happened when breweries aged the beers themselves instead of letting the pub do it. Porter became the first industrially-produced beer, and something brewed in huge volume inside huge wooden tuns. By huge, they were enormous: some held 5,000,000 pints of porter. And brewers had many of these massive wooden tuns. 

Those epic vessels were filled with dark beer and it was left for around six months as it slowly ‘staled’. Porter was initially robustly strong, around 7% ABV in the mid-1700s, heavily hopped, vinous and funky with Brettanomyces yeast (the name means ‘British fungus’ and it was first isolated and identified in porter). The time in tuns would’ve mellowed the beer, using the hops’ antibacterial qualities as the gatekeeper against any uninvited microorganisms, and allowing the Brettanomyces yeast to convert more of the malt’s sweetness, leaving something tarter and drier than the sweeter, milder version.

By the 1800s, ABV had dropped to around 5% ABV (because of higher taxes), but it was still long-matured in porter tuns, and it was London’s beer: in 1823, porter production topped 1.8 million barrels in London. But then the decline began as milds grew in popularity with drinkers favouring the sweeter, more bitter, less tart younger beers, and as other beer styles, like pale ale, started to become more prominent. A century after its peak, porter had effectively disappeared, and Stout had become the popular dark beer on the bar. 

Stout or porter, which came first?

Stout came before porter. Sort of, anyway: the name ‘stout’ was used before the name ‘porter,’ although stout wasn’t a style and instead it was used like we might use ‘Dubbel’ or ‘Imperial’ today – a prefix to explain that it was a stronger version of a regular beer.

Perhaps confusingly, ‘Imperial’ was also used back then and it was a designation of the strongest beer a brewery made, where imperial porter was actually used before imperial stout and you could’ve seen an Imperial Brown Stout Porter. Anyway…

Over time, and through a hard-to-trace dilution, stout came to refer to a strong dark beer and then just a family of dark beers, with breweries producing a range of Stouts from ‘single’ weaker ones through to Imperial-strength.

All of this would change through the World Wars when beer production was impacted by roasted barley rationing and a general change in taste, in part brought about through the commonly-held belief that ‘stout was good for you.’

As the wartime recovery took place, stout became the fashionable and ‘healthful’ beer while porter, much weakened by rationing, became an old-fashion relic that was left behind – indeed, it suffered a temporary extinction, disappearing for decades, until new microbrewers of the 1980s brought porter back.

Now porter is back and it sits with stout on bars and in fridges once again, where the modern brews taste nothing like those from the 18th century.