Stout vs Porter : What Is The Difference?

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. 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.

Let’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.

Porters 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.

According 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.

So, 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!