Distinguishing the difference between stout and porter can be a challenging prospect for even the most astute beer connoisseur. Although some might claim to be able to, the reality is there are not many people who would be able to tell them apart in a side-by-side visible comparison, and only a very small percentage would be able to actually determine their differences in a blind taste test.
The reason for this is that traditional porters and stouts are two of the world’s most closely connected beers, not just in how they look, smell, and taste but also historically. To compound the matter the explosion in popularity of craft beers and breweries has caused even more confusion as many of these breweries use the terms porter and stout interchangeably; with many of the beers they label as porters being in actuality stouts and vice versa.
Having said that if you surveyed a panel of brewers they would in all likelihood agree that the two main differences between these styles of beer come down to their grain bill and their history. Historically stouts are brewed using roasted unmalted barley and porters are brewed with malted barley, however now nowadays this is not always the case.
To help distinguish between their differences we will start by going back and taking a look at their origins…
The History of Stouts and Porters
Porters are actually the direct ancestors of stouts, with the first versions of the style showing up in the early 1700s when they quickly became a common beverage for factory workers in England at the time. When they first appeared on the scene porters were basically a stronger version of a brown ale with an ABV averaging around 6.5%. They became popular with publicans (pub owners) at the time due to the fact they could be served right away and did not require any aging.
Like any popular beer style, different brewers started experimenting and making different versions of it. One such version had a much higher alcohol percentage and became known as a Stout Porter, the stout referring to its stronger bolder taste and higher alcohol percentage.
Over time the name for this stronger style of Porter was shortened to simply Stout, and eventually, it became recognized as its own style.
Further distinctions between these two styles of beer began to occur in the early 1900s during WWI. As a result of grain shortages caused by the war, the alcohol percentages of Porters in England started dropping down to around 4%, whereas the Stouts that were brewed in Ireland continued to maintain a higher ABV. The use of less grain in the recipe accounted for the lower alcohol percentage in porters and also a lighter taste.
Stouts also started being brewed with unmalted and roasted barley as a result of a tax concession for using those grains versus the brown barley which Porters were made with at the time. These two distinctions became the primary differences between these styles.
The Differences Between Stout and Porter 
The following is a breakdown of the main differences between these two beer styles. However, it is again worth stressing that the following differences would only apply if the beers you are comparing are brewed in their traditional sense. In the majority of cases today they are not and as a result, it is very difficult if not impossible to tell them apart with some people claiming there is no difference between them, we tend to somewhat agree with that line of thinking.
The Barley – If a Porter & Stout are brewed in the traditional sense, the porter will be brewed using malted barley whereas a stout is brewed using unmalted roasted barley. This distinction in grains results in the following two differences.
Appearance – The first difference in these beers as a result of the grains used to brew them will be noticed in their appearance. A Stout will be slightly darker with a color ranging from dark ruby to black, while Porter’s having originated from brown ales should lean towards being a medium to darker brown color. Both will have a white to tan colored head.
Flavor – Another distinction created by the different grains used to make them will be in their taste. Due to the use of roasted barley Stouts should have a roasted somewhat burnt flavor to them, which will not be present in a Porter. Both can have coffee, chocolate, and carmel flavors depending on the rest of the grain bill used.
Types of Stouts
The following are the 3 main types of stouts…
Irish Stout – Also commonly referred to as a Dry Irish Stout. Contrary to their appearance they are not a heavy beer and in many circles are considered a light beer, with most coming in with a lower ABV of between 4 – 4.5%. Guinness extra stout and draught are the most famous versions of this style. They have a light coffee and creamy flavor.
Oatmeal Stout – These stouts are similar to dry Irish stouts except an oatmeal stout recipe will include a small amount of oats in the grain bill used to make them. The oats give them a fuller body and a slightly sweeter taste as well as larger head retention.
Imperial Stout – Any beer that has imperial as a prefix is a beer that is a bigger and fuller-bodied version of the original, many times it also means that it will have a higher alcohol content. Such is the case with Imperial Stouts, they have more intense flavors and are higher in alcohol.
Types of Porters
The following are the 3 main types of porters…
Baltic Porter – Unlike all of the other examples of these beer styles a Baltic porter is not an ale but a lager. They are in essence a lager version of an Imperial Stout. As a result, they are fermented cold and lagered which results in a smooth clean taste. They will usually have characteristics of chocolate, carmel, and nuts. They also typically have a higher ABV ranging from 6.5 – 9.5%.
American Porter – These beers are the American take on the old-English Porters and could even be considered an aggressive version of them. They typically have a higher ABV ranging from 4.8 – 6.5%, they are slightly darker and stronger tasting with notes of coffee and chocolate.
English Porter – Also called a Brown porter is the original version of this beer style, first brewed approximately 300 years ago. Unlike a stout, it will not have any roast flavors but will lean towards a malty nutty taste with notes of chocolate and caramel. Color wise it is a medium to dark brown beer with an average ABV of 4.5 – 5%.
Last Call
In modern times the only clear difference between stout and porter should be the unmalted roasted barley used to brew a stout and the malted barley used to brew a porter, outside of that the lines between their differences become blurred and it really comes down to the preferences of the brewer.
P.S. If you brew your own beer, pick up your gift of our top 5 favorite recipes from Big Robb’s brewpub. Details are on the side of the blog or at the bottom if you are on your phone. Cheers!