Is There A Difference Between Porter and Stout?

Is There A Difference Between Porter and Stout? 

Yes, they are fraternal twins. Stouts and porters are brewed from the same recipe of a mix of brown and pale malt. By pulling off less wort the English were able to make a beer called Brown Stout. Pulling more wort off the next batch they made a beer called Porter. Both beers were dark ales, born of the same mother but different. Brown Stout had an alias, “Strong Porter”. Was this the genesis of the question? At this point in the early 1800s I would say the answer is no. If you put water in your whiskey is the drink no longer whiskey?

I would take the position that the introduction of Patent Malt (Black Malt today) in 1817 was where the difference began. It was a cheaper way to make the same beer. By the late 1800s Roasted Barley came into the picture.  Wars, Taxes, and Prohibition left its mark on Stouts and Porters inevitably widening the difference. This time period saw the ABV reduction in Stouts and Porter each to different levels furthering the divide.

By this time we get to the mid-1900s, after the repeal of prohibition. Big beer, was coming to the forefront, providing their brands in mass quantities to the masses. Stouts and Porters although not forgotten were hard to find. I know that Guinness Stout was the first Stout I had. I don’t recall that occurring until I was in the Navy in the late ‘80s. I only knew the existence of Porter by watching the John Wayne movie, “The Quiet Man”.

I do know this. The Craft Beer Revolution in this country has brought back all the beers including Stouts and Porters.

With the Craft Beer Revolution beginning in the late 20th Century the Beer Judge Certification Program (BJCP) was founded. This occurred in 1985 as a joint venture between the American Homebrewers Association and Home Wine and Beer Trade Association. The purpose of the BJCP was to provide specific guidelines for each beer style4. The most recent edition is the 2015 edition. In the 2015 edition there are a total of 12 styles of Porters and Stouts. When including the specification for Wood-Aged Beers & Specialty Wood-Aged Beers the number of styles for Porters & Stouts increases to 36.

The BJCP clearly shows there are clear differences in the recipes and the quantifiable statistics required of each of the four Porters and eight Stouts. Same goes for the individual’s perception of Aroma, Appearance, Flavors, and Mouthfeel.

Here is a personal example. Recently (September 2018) Arrogant Bastard became Arrogant Consortia. They are continuing to make Arrogant Bastard. They are adding two more beers. Enter Night Pilsner (a colab with Metallica), and Black Metallic Stout.

This Stout has a not velvety but borderline creamy head with a full-bodied mouthfeel. This beer is 7.2% ABV with a Roasty malt flavor. It’s a Stout. It is over the top on IBU though. 75 IBU. An awesome bitter back end to coincide with hoppy aroma going into the experience. Quantifiable doesn’t cover this. This beer is part Stout, part IPA.  I call it an India Black Stout (IBS). This beer is way past what you might call a Cascadian Dark Ale or a Black IPA. This is a Stout that gives an IPA lover the benefit of both beers. You will also never see it judged in a BJCP sanctioned event. There is no category for it.

So, here’s the curveball to my conclusion. If you’re not a BJCP certified judge. If you don’t have the palate, nose, or eyesight to tell the differences in all aspects of these two fantastic styles of beer. My question to you is, “Does it really matter if the beer is a Stout or a Porter if you like it?”

Fraternal twins. Yes, there are many similarities between these two Styles of beer. History tells us their origin was from the same recipe. That said, we are somewhere around, at least 270 years since that time. The unfortunate truth is most of us are not willing to take the time to learn how to discern those differences. If you can’t do that, then why worry about the name? Enjoy your Stout or Porter. Maybe if I drink enough of them and you drink enough of them, we can have a good time debating not if there’s a difference. The debate will be which is better Stout or Porter. To make it perfectly clear. There is unequivocally a difference between Stouts and Porters.

Additional Information

Below is a synopsis of information I used in coming to my conclusion and includes definitions used in brewing beer, history for Stouts & Porters, and statistics used in the BJCP.


Mash: The term for the hot water steeping of the various grains used in brewing. After grinding the grains into “grist” the hydration of the grains activates the malt enzymes, converting the grain starches into fermentable sugars.2

Wort: The aqueous solution of extract made from grain, intended for fermentation by yeast into beer. Wort is created through the process of mashing.2

Parti-gyled: Getting multiple beers out of the same mash. The brewer boils successive runs separately, then blending them to different strengths.1

IBU – International Bitterness Unit. The measure of a beer’s bitterness.4

SRM- A scale for measure of a beer color density more than hue/tint.4

OG- The Specific Gravity of unfermented wort.3

FG- The Specific Gravity of fermented beer.3

ABV- Alcohol By Volume (%)4


1750 to 1816: Two types of beer produced from same recipe of using Pale & Brown malt. Porter & Brown Stout (Strong Porter). Brown Stout is made from drawing less wort off the mash making it a beer with higher ABV.

By the end of this time period there were multiple styles of beer Porter, Pale Stout, Brown Stout, Slender Porter. These were made from two recipes with different ABVs.

1817-1880: In 1817, Patent malt became available. Today this malt is also called Black Malt.3 This provided a cheaper way of brewing Porter with almost entirely pale malts instead of the previous method of using a mixture of brown and pale malts.

As time passed, the use of parti-gyling was used to brew four porter/stout style beers made from pale and brown malt only.

Keeping Porter: A Porter that was good for aging

Single Stout, Double Stout, &Triple Stout: Using parti-gyling techniques of using the same grain in as many as four mashes. Each mash making a lower ABV beer, then mixing various volume ratios in order to obtain the desired ABV for each beer.1

1880-Present: In 1880 a new law in the United Kingdom allowed the use of Roasted Barley. Guinness did not include roasted barley in their Stouts until 1930.1

World War 1 led to high taxes and requirements for the lowering of ABV content in Stouts and Porters. Porters down to 3.6% ABV and Stouts to 4.7% ABV. Guinness Extra Stout which was 7.7% ABV in the late 1800s is still down at 4.2% today.1

Beer Judge Certification Program (BJCP)4 Requirements for Stouts and Porters

I don’t want to go into detail on the Vital Statistics. Boring you with numbers is not my goal. I will describe a few things I found.  These are the quantifiable similarities between Stouts & Porters.

  • Baltic Porter (6.5-9.5%) & Imperial Stout (8.0-12.0%) had the highest ABV content ranges for Stouts & Porters
  • Baltic Porter & Sweet Stout had the same IBU range (20-40)
  • American Porter & Oatmeal Stout had the same SRM range (22-40)
  • Pre-Prohibition Porter and American Porter which are both American beers (the US was the only country to have a Prohibition) have no Vital Statistics in common.

Below are the general descriptions of differences between Stouts & Porters with respect to Aroma, Appearance, Flavor, and Mouthfeel. These are the qualifiable differences between Stouts and Porters.

  • Aroma is chaotic with respect to the smell of the Stouts & Porters. Roasted, Coffee, Malty Sweetness and Chocolate. The BJCP does not mention other aromatic additives such as Coconut, Peanut Butter or even extra hops.
  • Porters based on SRM and Appearance can be anywhere from a Deep Red color to Opaque Black. Stouts tend to be essentially very dark brown to Deep Black or Opaque. We’re impressed you’ve made it this far into the research material. We will send a decal to the first five readers that send us a note referencing this article. 
  • Flavors are all over the map from fruity to burnt chocolate. Roasted malt to Black Malt. Add to the Craft Beer Industry of today where Coconut, Peanut Butter, and Peppers are added to both Stouts & Porters which are not discussed at all in the BJCP.
  • Stouts are full-bodied in Mouthfeel. Where Porters, except for Baltic Porter, are light or medium bodied. Porters are medium to highly carbonated, except for Baltic Porter. Stouts tend toward lower levels of carbonation.

Referenced sources for this article

  1. The Difference Between Porter and Stout, The Beer Connoisseur, Martyn Cornell, 03/14/2016
  2. Beer & Brewing Magazine
  3. Center of the Universe Brewing Company,
  4. Beer Judge Certification Program, 2015 Style Guidelines
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Guinness Stout A Classic


Regis Schmerheim

10 thoughts on “Is There A Difference Between Porter and Stout?”

  1. “Does it really matter if the beer is a Stout or a Porter if you like it?”
    It might help if you prefer Porters to Stouts (or vice versa) when you’re deciding on a new beer to try? Though considering how muddled the style definitions are it may not matter. My understanding is that stouts typically have more roasted malt flavors (though robust porter goes into this territory) and have a higher bitterness than porters do.

    Also I’d like a decal?

      1. I was a bit ashamed recently when a good friend and drinking buddy asked me what the difference between porter and stout, and I didn’t really have an educated answer. I appreciate having the additional historical perspective as well. Am I too late for a decal?

  2. Still giving out decals? 🙂

    Great article. I’ve struggled with the difference between these two since I started brewing. I really think they are very close and some beers could really qualify as either. I think, for me, what really determines the difference is the ABV and mouthfeel.

  3. “Porters based on SRM and Appearance can be anywhere from a Deep Red color to Opaque Black. Stouts tend to be essentially very dark brown to Deep Black or Opaque. We’re impressed you’ve made it this far into the research material. We will send a decal to the first five readers that send us a note referencing this article. ”

    I read it this far because it was very interesting as this is a question I often wonder. And I definitely want a decal! I’m in mainland europe tho.

    To add my two cents, I found a lot of threads in American homebrew forums saying that the main difference (technically) is that porter don’t have roasted barley.

  4. BJCP Judge here and retail account manager. While I commend your attempt here, you miss some key elements in the debate.

    Firstly, your basic assumption regarding the BJCP is an easy one to make: that it is a definitive set of guidelines. While the style guidelines are no doubt exhaustive, they are what we use when judging (primarily home brewed) beer. The Brewers’ Association has its own set of style guidelines, which are used in it’s events, which are almost exclusively commercial beer. These guidelines – while not as verbose – identify more distinct styles, and does not always show matching vital stats to what the BJCP does.

    Your second assumption, and this is perhaps much bigger, is that all brewers are making their beer strictly to style and labeling thusly. While there are some brewers that do, the vast majority do not. Classic interpretations of classic styles have a place, but are not going to keep the lights on for most places. The distinction between stouts and porters is easily muddles, and from my experience I can only deduce that the vast majority of naming is done out of personal preference rather than an attempt at style conformity.

  5. Just had this argument with a buddy of mine the other day. The biggest differences I’ve always claimed is the carbonation and body, I really like the lower carbonation and fuller body of stouts. P.s. were you serious about the medal?

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