Porter vs. Stout: Really, what is the difference?

‘What exactly is the difference between stout and porter?’ someone  recently asked me. As I opened my mouth to explain, I realized that the answer is not as cut and dry as you might think.

While there are many varieties of so-called ‘dark beer’ such as schwarzbier, Scotch ale, dark American lager etc., the broad categories of stout and porter are probably the most well known. Actually, their histories are so intertwined that honestly I still get confused – what came first? The porter or the stout?

I was chatting recently with my friend Scott at Blank Slate Brewing Company about the differences and asked him how he approaches this topic with people. He responded that first, he likes to take a step back. He explains that as you go up the style chain, beers generally increase in flavor, body, and intensity (though there are some exceptions). If you think about the differences between a blonde ale and pale ale, or amber and brown ale this premise fits the bill. Porter and stout are a similar story, but with a lot more overlap.

DSC_0022Let’s take a look at what the Beer Judge Certification Program (BJCP) style guidelines, the industry standard, say:

“{Dry stout} evolved from attempts to capitalize on the success of London porters, but originally reflected a fuller, creamier, more “stout” body and strength. When a brewery offered a stout and a porter, the stout was always the stronger beer.”

So that’s how ‘stout’ came to be, but there are so many variations on both styles these days I knew there had to be more to the tale.  I investigated even further, this time delving into The Oxford Companion to Beer, which confirmed that the story of porter and stout is indeed a murky tale. What we do know is that porter surfaced in London sometime in the 1700s. It was named for the strong, portly workers (porters…) who drank it.

homebrewed vanilla porterPorters and stouts share dark malts, which give them their classic black, or near-black, color. Before the advent of modern day kilning, most beers were on the darker side because grains were frequently roasted over open flames.

As far as our understanding of the first porter’s ingredients and process goes, we know it was made mostly of such ‘brown malts,’ and was frequently aged in wood barrels for varying lengths of time. All of this variation meant porter from batch to batch tasted differently (and probably had some funky, even sour, barrel aged characteristic). Frequently the beer was blended at the pub where it was served.

As the popularity of porter and ‘stout porter’ grew and time went on, it morphed and changed based on region. Black patent malt was discovered in the 1800’s – this discovery meant a lower percentage of dark malts could be used, which increased brewing efficiency since dark malts have little fermentable sugars. Eventually sub-styles of porters/stouts emerged, such as Baltic Porter – a lagered, stronger version that was exported to the Baltics.

DSC_0295According to our modern day guidelines there are three distinct categories for porter – Brown, Robust, and Baltic. For stout, we have Dry, Sweet (subcategory Milk Stout), Oatmeal, Foreign Extra Stout, American Stout, and the big daddy, Russian Imperial Stout.

This graphic depiction found on coolinfographics.com does a pretty great job of visually describing the different styles and where they fall on the spectrum.3771122910_4a6c3ea496_o

As you see, though people talk of porter and stout as two distinct beers, in reality there are many variations and substantial overlap across the styles. For example, a Dry Stout will generally be a bit more bitter, have less body, and be lighter than its cousin ‘Robust Porter.’  In the same way that some pale ales seem more like IPAs or vice versa, so is the case with versions of stout and porter. One similarity across the stouts is they are more likely to contain roasted barley as opposed to most porters (though Robust Porter may have some).

In the end, the brewer is responsible for what style to call their beer. Sometimes you just have to take a sip and see for yourself!

22 thoughts on “Porter vs. Stout: Really, what is the difference?”

  1. This is a little off topic, but a pic in this post remined me.
    When you put something on nitro, how are you carbing? Carb with CO2 then dispense with nitro, or carb with the beer gas? I’ve read that both are doable. I’m thinking about adding a nitro tank to my setup and I’m curious how you go about it.
    Thanks.

    1. With our system we carb and dispense with beer gas (75/25 nitro to CO2). We’re actually going to be writing an entire post all about the nitro tap we put together so stay tuned for that!

    1. Sorry if I wasn’t clear here, I thought it would be redundant to say that porter was named after porter, I literally meant that when I said that ‘It was named for the strong, portly workers who drank it’ (aka porters). I can add that if you think it’s not clear though!

      1. No, you said it again. “Portly” means fat. “Porter” means someone that carries stuff for a living. Two completely different words. Porters have all different body shapes, including skinny.

  2. Close, but not entirely correct. Darker beers were the norm in days of old, the consequence of less refined malting methods – open flame, direct heat, poor humidity control, etc – giving brown and amber, strong or mild, as the only ale options. In Britain, it was usual to blend beers from the tap, to the taste of the consumer – half-&-half, three-threads, or whatever – until one bright brewer (Harwood) in the 1790s devised an “entire” ale that fitted the bill for the porters & carters of London. Consistent, not too strong, but robust enough. Thus “porter” was born. Porter came to dominate the whole British ale market. When black, “patent” malt became available in the early 1800s, porter got darker. Some breweries began to offer stronger, stouter versions – “Stout Porter” – as the market differentiated. Eventually, “Stout” emerged as a different product, with darker base malts, and roasted barley, providing the colour, along with oats, or milk sugar, & other adjuncts to increase the gravity – and alcohol content. Porter used a higher proposition of the newer pale malts along with patent malt to give a medium-bodied black beer.

    Shonky producers slipped darkening adulterants onto their brews, giving porter a bad rep, so when the delicious pale ales of Burton-on-Trent arrived, the once dominant porter lost market share. Porter has enjoyed a revival in recent years, because it offers full flavour with less alcohol – a more session-friendly dark beer. Baltic Porter is a little different, brewed with lager yeast to cope with cooler conditions, with more hops & higher alcohol to last long voyages.

    1. Thanks for your comment – Above all, my point with this post was to give a brief history but more remark on the similarities in modern day porters and stouts. In the current craft beer landscape of the United States, there is substantial overlap between styles that practically blurs the line between them. For example a dry stout like Guinness will be much ‘lighter’ as compared to a robust porter like Edmund Fitzgerald. As much as we want to put porter and stout into two separate buckets, that categorization is largely arbitrary and defined by the brewers that name them.

    2. Dean, there is barely a “fact” in your narrative that is correct. The “Harwood invented porter” story was debunked years ago. Porter was around from at least the early 1720s, not the 1790s. Three-threads had nothing to do with porter. Porter didn’t lose market share to Burton pale ales, but mild ales. And so on.

  3. As I understand it, Baltic Porters were made in and around the Baltic states, not exported to the area. Lager yeast was used as it fermented better at the lower temperatures in this region.

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