It's one of the questions we get asked most often on our tastings, usually somewhere between the third and fourth taproom: what's actually the difference between a stout and a porter? The honest answer is that the two styles have been tangled up with each other since the 1700s, and the line between them has never been perfectly clean. But there is a real history and a real (if blurry) set of brewing differences behind the two names, and once you know what to look for, you'll taste it. We've been pouring dark beers on our tours through London's independent taprooms since 2014, so here's our attempt at a straight answer.
Porter came first
Porter is widely credited as a London invention of the early 18th century — a dark, hopped beer made from brown malt that became hugely popular with the city's manual labourers, including the street and river porters who are usually cited as the reason for the name. London brewers produced porter in enormous volumes through the 1700s and into the 1800s, and for a long stretch it was arguably the world's first truly industrial beer style, brewed at a scale that older, smaller breweries simply couldn't match. Our own short history of London beer covers this era in more detail, including the notorious 1814 Beer Flood, which happened at a porter brewery in what's now Tottenham Court Road.
Then "stout" split off
Stout didn't start as a separate style — it started as an adjective. Brewers made "stout porters": stronger, fuller-bodied versions of their standard porter, aimed at drinkers who wanted more body and more alcohol for their money. Over the following decades "stout" gradually became a name in its own right rather than just a description of a beer's strength, and by the 19th century breweries were selling stout as a distinct product line, with porter itself slowly declining in popularity through the 1900s. Guinness is the best-known example of this shift — its earliest beers in the 1700s were porters and stout porters, long before the brand became synonymous with the dry stout style it's known for today. If you want the full story of Guinness's own London presence, we've written a separate visitor guide to the Guinness Open Gate Brewery in Covent Garden.
So what actually separates them today?
Modern brewers don't follow the historical strength rule at all, so you can't use ABV to tell a stout from a porter — both range from session-strength beers around 4% right up to imperial versions well past 8%. The more useful distinction is the malt bill:
- Porter is traditionally brewed with brown and amber malts, giving a smoother, rounder dark-malt character — often more toffee, biscuit or light chocolate than sharply roasted.
- Stout typically leans on roasted, unmalted barley alongside its malted grains, which is what produces that sharper, coffee-and-dark-chocolate bitterness and the thicker, sometimes almost creamy mouthfeel people associate with a classic dry stout.
- Nitrogen serving is common for stouts (think the cascading pour and tight head on a nitro stout) but isn't part of the style definition — porters can be nitro too, and plenty of stouts are served on standard CO2 like any other keg or cask beer.
In practice, plenty of brewers treat the two names as close to interchangeable, and you'll find porters that taste more roasty than some stouts, and stouts that lean smooth and sweet rather than sharp. If a can or a taproom board doesn't tell you the malt bill, the name alone won't guarantee much — which is exactly why tasting them side by side is more useful than reading about them.
How the two compare to other dark and pale styles
Stout and porter both sit at the darker, maltier end of the spectrum, which puts them in useful contrast with paler styles most drinkers know better. If you've read our guide to lager vs ale, you'll know stout and porter are both ales, brewed with top-fermenting yeast at warmer temperatures, unlike the cold-fermented lagers that dominate the mainstream market. And if hoppy, pale styles are more your usual order, our explainer on what IPA actually stands for covers the other end of the spectrum, where bitterness comes from hops rather than roasted malt.
Where to actually taste the difference
Reading about malt bills only gets you so far — the difference is obvious the moment you put a good porter and a good stout side by side. On our Bermondsey Beer Tasting Tour — 2-3.5 hours, £49 per person, beer included, across four independent taprooms in the Bermondsey railway arches, meeting at Southwark Brewing Co, 46 Druid St — dark beers regularly feature alongside the pale ales and IPAs, and it's the kind of thing our guides are happy to line up for a table that wants to compare styles rather than just work through a tasting flight. Independent taprooms tend to rotate their dark beers more often than big supermarket shelves do, so what's pouring on the day varies — ask at the bar if you're chasing something specific.
A note on strength and pacing
Because dark beers can run stronger and richer than a standard lager, it's worth pacing yourself the same way you would with any tasting flight — our guide to how many units are in a pint of beer is a useful reference if you want to keep track across an afternoon of tastings rather than guess.
Bringing a group along
If a stout-vs-porter debate is the kind of thing your friends or colleagues would actually enjoy arguing about over a few tasting glasses, it works well as a private outing — we run private groups from 6 up to 60+ people, and it's a genuinely good excuse for a work social or a birthday group that wants more structure than "meet at the pub". Gift vouchers are bought directly on our gift vouchers page, delivered instantly by email and never expire, so a stout fan on your list doesn't need to use theirs before a specific date.
The bottom line
Porter came first, as a London-born style brewed on an industrial scale in the 18th century. Stout began as a strength descriptor — a "stout porter" — before splitting off into its own name and, eventually, its own identity built around roasted barley and a sharper, thicker character. The names still overlap more than most style guides admit, so the most honest answer to "what's the difference?" is: taste a good example of each and decide for yourself which one you actually prefer.