What is the Difference Between Porter and Stout
This question gets asked a lot. "What is the difference between porter and stout" is probably the first thing that people ask me after they find out that I am a Certified Cicerone*. Most folks figure out for themselves an answer that lets them sleep at night, but, as with all things beer, the answer is nuanced and can be as complicated as you want it to be. I’m gonna aim for a nice medium-complex answer.
Short Answer
Porter and Stout have a lot of overlapping traits. They are both, dark, bitter, chocolatey, and roasty. On average, stouts are going to be more bitter, roastier, a bit darker, and have a higher abv. Stouts are more stout, you could say. Certain types of Stouts overlap pretty completely with certain types of Porters. Unfortunately for this short answer, there are actually several different categories of both Stouts and Porters that, due to this style’s impressive history, are all completely different from each other. A Dry Irish Stout is absolutely nothing like a Russian Imperial Stout and neither of those is anything like a Porter, so let's get into the long answer.
Better Answer
If you really want to know what the difference between Porters and Stouts is, you need the better answer. This is far from complete, but it’s a good crack. The short answer above applies best to American Stouts and American Porters so it will still be accurate in most of the conversations you will likely have here in America. However, as you know, breweries don’t really care what country they are in when it comes to what they brew, and many craft beer drinkers will gladly go toe to toe to out beer-knowledge you, so let’s make sure you have both barrels loaded. These beers are very alike in appearance and flavor, so a lot of the difference is historical. You'll have to forgive the history lesson you are about to get.
Stout was originally a spin-off of Porter. Breweries would offer a Porter and would sometimes offer a “Stout Porter” which was a stronger, stouter version of the Porter. Guinness, famous for brewing the archetypical Dry Irish Stout, originally brewed a Porter and a "Stout Porter". Eventually, Stout Porters grew so popular that they dropped the porter half and went on their merry way. The practice of making beers hoppier and more alcoholic to increase their shelf life for export led to the creation of beers like the Irish Export Stout (a stouter Dry Irish Stout as brewed by Guinness) and the Imperial Stout. Exported Stouts sent towards the Baltic Sea planted the seeds of desire for a strong dark beer that eventually spun off into the Baltic Porter, a style of Porter that is usually fermented cold and is much stouter than normal Porter and indeed even stouter than most Stouts, but not quite as stout as the Imperial Stout. Porter begat Stout which begat Imperial Stout which begat Baltic Porter. As you can see, there’s overlap.
See, back then straight up lying to everyone was just as chill as it is today.
Meanwhile, back in Western Europe, Stout is getting marketed as a healthy drink. You may have heard of the old marketing, “Guinness makes you strong” which was a popular idea, so people started chucking oatmeal into their stouts to make them “healthier,” leading to the creation of Oatmeal Stout. And if you have a health drink that tastes like a Stout, that is, it's bitter, and you want to sell it to a wider audience, you chuck some creamy, delicious, non-fermentable, lactose in to make it yummier and now you have the Milk Stout, a healthy drink ideal for nursing mothers. You can’t make this up, that is really how Milk Stouts (now called Sweet Stouts) were marketed in the early 1900’s. None of this has anything to do with Porters at all except for the fact that these are probably the easier Stouts to not accidentally confuse with Porters, which by this time had gone completely out of style and basically didn’t exist anymore.
Back to the present craft beer era, everyone is brewing porters again. Americans brew a darker, stronger Porter than the British whose Porter slightly more closely resembles a Brown beer. We have our own version of the Stout as well that reflect our tastes, that is, ADD MORE HOPS. We also took the British Imperial Stouts and did our own thing with them (more hops, more roast, and more booze) which resulted in the flavor bomb that is the American Imperial Stout. Heaven forbid you ever stumble on the Imperial Porter which is the abomination bastard son of the American Imperial Stout and Porter born out of our American love of taking something and doing it harder.
Did that answer all your questions? Let’s review. Stout is typically stronger and darker than Porter, though they are sometimes so similar that much of the difference is historical. In the beginning, there was Porter. Stout was a stronger version of that that eventually became its own beer. Porter died off. Stout spun off into a bunch of other Stouts: the Imperial, Oatmeal, and Sweet (I didn’t even mention the Tropical Stout, which is its own thing). Porter came back, closer to its original brown form in England (I also didn’t mention the “Robust Porter” which is a real thing and I swear to Ninkasi is a beer created to troll us all), and closer to its Stout form in America. My 1000 word description, of course, misses a ton of the nuances of history and flavor, so if you want to know more, and who wouldn’t, you can read Terry Foster’s Porter (affiliate link) or the BJCP Style Guidelines which is where I got much of my information for this post. Thanks for reading. Prost!
*Hey by the way, did you know that I am a Certified Cicerone? I don’t know if I ever mentioned that. I usually don’t talk about it. Anyway, I’m a Cicerone.