101 // Stout vs. Porter

Two popular styles, many popular definitions

Story by Adrienne So // Photography by Shelby Brakken

If you find yourself sitting at a bar with time to kill, consider bringing up the age-old beer enthusiast’s version of the chicken-or-the-egg debate to your drinking companions: What, exactly, is the difference between a porter and a stout? You might want to order yourself another round after you ask, because the answer may take a while.

A few moments spent perusing beer forums—a pastime undertaken usually by only the most masochistic of beer enthusiasts—reveals many different definitions for both porter and stout. Stouts have always seemed like a best friend’s older brother: intimidating, dark, and brooding, yet surprisingly mild and low in alcohol content. For instance, imperial stouts notwithstanding, a pint of Guinness is a lot friendlier than it looks.

And if a stout were your best friend’s older brother, then a porter would be the neighborhood drug dealer, always lurking around the corner but never fully materializing. Most people can name a stout or two that they enjoy, but coming up with a short list of porters is always more difficult. Few porters enjoy the popularity or ubiquity of a Guinness or a Murphy’s.

Other beer drinkers (perhaps ones with less of a tendency to overly anthropomorphize their beverages) characterize a stout by a predominance of roasted flavors, in contrast to a porter’s overtly hoppy and caramel flavors. “I think the higher use of roasted barley and/or black patent malt in stouts differentiates them from porter malt recipes,” says Cam O’Connor, brewmaster at Deschutes Brewery in Bend, Oregon, whose Black Butte Porter and Obsidian Stout are two of the most prominent examples of these genres on the West Coast. “Most of the porter recipes I have seen and used don’t include very much, if any, roasted barley or black patent specialty malts,” O’Connor says.

Still others hold to Fred Eckhardt’s comprehensive book The Essentials of Beer Style—published in 1989, during American craft brewing’s infancy—which says that porters are dry, with more intense malt and hop flavors than stouts. But this definition seems to apply more to the traditional Irish stout—like Mendocino’s Black Hawk Stout—which has its own sub-category in the Beer Judge Certification Program (BJCP) and fails to take into account the dozens of existent stout varieties, like milk stout and oatmeal stout.

“Sometimes I think the only difference between a porter and a stout is what the brewer decides to call it to enter a competition,” said Carl Singmaster, the “chief beer officer” of Portland bottle shop Belmont Station. The BJCP defines a porter as having a slightly lower SRM value than stouts do. SRM stands for Standard Reference Method and refers to the time-honored—at least, for the past 50 years—technique of measuring how much light is lost as the beam passes through a centimeter of beer.

Since few beer drinkers (or judges, for that matter) come equipped with specialized light-measuring equipment, the best way to judge a beer’s color is by placing a few centimeters of it in a clear glass, on a white background, and matching it to the BJCP’s color scale (bjcp.org). A porter in competition should generally have between 20–35 SRM units, while a stout’s should extend from 30 to more than 40.

An historical perspective might come in handy for those of us who find beer color a far too dry and technical distinction between a porter and a stout. Literary references to a style of beer called “porter” first emerged in the mid-1700s. Popular legend has it that brewers and bartenders got tired of tapping separate kegs for each of the current three styles: “beer,” “ale,” and “twopenny” (a beverage of specious origins most famous for being cheap). Brewers combined them into one brew that became popular with London laborers, who then gave the new style their own name. The new style of beer, porter, was occasionally called “entire” or “entire butt,” after the cask in which the beer was stored.

The late beer writer Michael Jackson thumbed his nose at the “three-threads” story. Instead, Jackson proposed that the porter style emerged as a result of brewers combining different mash runs from the same malt. For whatever reason, porter became popular at the exact instant that the Industrial Revolution started making transportation networks faster and more efficient. An enterprising bloke in Dublin, who went by the name of Arthur Guinness, banked on the popularity of porter in 1798, killing off Guinness’s original Dublin ale in favor of Guinness’s East and West India Porter.

As Guinness’ name shows, porter was virtually synonymous with the British Empire and its spheres of influence. Guinness traveled as far away as the New World and China. However, that didn’t mean that breweries stopped experimenting with darker beer. Beer historian Ron Pattinson, who writes the blog Shut Up About Barclay Perkins (barclayperkins.blogspot.com), pinpoints the exact difference between stouts and porters by time period. Pattinson examines the mid-19th century recipes for stout and porter at Whitbread, the once eminent British brewery. He then concludes that the only difference between porter and stout is the amount of water used.

But Whitbread wasn’t the only brewery to continue evolving. As the empire waned, so, likely, did the popularity of porter. In 1821, Arthur Guinness II wrote down the precise recipe for Guinness Extra Superior Porter, which was the direct predecessor to Guinness Stout. Stout is the colloquial term for strong referred to by the “Extra Superior” in the beer’s title. Eventually, the stout porter was referred to simply as stout.

By the mid-20th century, stout was the unquestioned winner in the dark beer popularity contest. After World War II, porters had vanished into obscurity and those remaining evolved into British mild ales, until Michael Jackson and several other breweries—including, notably, San Francisco’s Anchor Steam—began reviving porter’s popularity, though not without some confusion on the part of us drinkers.

“Throughout the years, people just flop around the nametags for marketing purposes,” says Bill Manley, the communications coordinator for Sierra Nevada, whose porter and stout are remarkably free of clever marketing devices. As always, American craft brewers have taken creative liberties with each of the styles, adding chocolate, coffee, and chili peppers as they see fit, perpetrating further crimes upon the definitions of the styles, even if they do perpetrate deliciousness on our taste buds.

“It’s open to interpretation at this point,” Manley says. “I don’t think there are too many sacred cows in the world of brewing right now.”

So, to recap: In competition, stouts are darker. Their recipes tend to be characterized by the use of roasted barley, and they use less water than porters. And when you’re sitting at the bar next to your equally beer-geeky buddy pondering the tap list, the answer, as it often is when confronted with the ingenuity of American craft brewers, is that the difference is whatever you want it to be.