What Type Of Beer Is Guinness Exactly? (Detailed Explanation)

Guinness is one of the few alcoholic brands at the very top in terms of experience and expertise. This alcoholic drink has solidified itself as elite in over 150 countries, especially in its origin country, Ireland. With a reputation this massive, it is only fitting to understand the type of beer Guinness is. Here’s a quick answer.

Guinness is best classified as an Irish Stout because of its high bitterness (IBU of 35-40), very dark color (SRM of 38), the alcohol content of 4.2-5.6%, and being top-fermented rather than bottom-fermented.

But there’s more to Guinness than this quick answer. In this article, we will give a detailed explanation of why Guinness is classified as an ale, not a lager. Also, we will examine the specific type of ale it is, considering the reasoning behind that choice fully. Additionally, we will overview the brief history behind Guinness being an Irish stout and how its different variants fit into this definition.

You’re in for a ride, so let’s dig in!

Is Guinness A Lager Or Ale?

There are two broad categories of beers – lagers and ales. The primary difference between the two categories is how the beer is fermented. The two main fermentation techniques are top-fermenting and bottom-fermenting.

If the beer is fermented with top-fermenting yeast at warm temperatures (60˚–70˚F), it is regarded as an ale. On the other hand, if the beer is fermented with bottom-fermenting yeast at colder temperatures (35˚–50˚F), it is a lager.

Considering that Guinness is a top-fermented beer at warm temperatures, it is regarded as an ale. However, grouping Guinness into the ale category is just the first step in its classification. There are several sub-categories under the broad ale category, which leads us to the next section.

What Kind Of Ale Is Guinness?

As established, there are different sub-categories of beers. We will classify Guinness more explicitly using the Beer Judge Certification Program guidelines.

According to the guidelines of the Organization, Guinness is classified as an Irish Beer. To narrow it down even further, it is under the Irish Stout sub-category.

Because the Guinness Company boasts a rather extensive array of alcoholic drinks, some Guinness beer types may also fall into the Irish Extra Stout category.

However, considering the similarities between the two categories and the fact that most Guinness alcoholic drinks fall into the former category, we can boldly place Guinness under the Irish Stout category.

Now that we have that out of the way, the next natural question is why Guinness falls under this category, and we’ll detail that below.

Curious to know what we think about Guinness? You’ll find our review here.

Why Is Guinness An Irish Stout?

While classifying beers into either ales or lager is relatively straightforward, usually just considering the fermentation technique, classifying them into different sub-categories is not nearly as easy.

Five factors influence the final decision of a beer’s sub-category. They include bitterness (measured in IBU), color intensity (measured in SRM), original gravity, final gravity, and alcohol by volume of the beer.

The first factor we will examine is bitterness. According to the Beer Judge Certification Program guidelines, Irish Stout beers have an IBU between 25 and 45. For context, the IBU (International Bitterness Units) is a scale that measures the bitterness of a beer. The higher the value, the more bitter the beer is. Guinness beers typically have an IBU between 35 and 40. Since this falls within the standard guidelines, it meets the first criterion for being classified as an Irish Stout.

The next factor we will consider is the color intensity of the beer, measured in SRM (Standard Reference Method). The SRM of the beer increases with the increasing darkness of the beer. In other words, darker beers will have higher SRM values.

According to the standard guidelines, the recommended SRM value for Irish Stout ranges between 25 and 40. Guinness typically has an SRM of 38, meaning it meets the color intensity requirements of beer.

Aside from color and bitterness, the beer’s gravities are essential in determining the sub-category of the beer. Actually, there are two different gravities in place – the original (OG) and the final (FG). Original gravity measures the sugar content before alcoholic fermentation, while the final gravity measures the unfermentable sugars in the beer after fermentation.

The OG of Guinness is 1.050, which is just slightly above the recommended 1.036 – 1.044. The FG, meanwhile, is 1.009, which falls within the recommended 1.007 – 1.011 provided by the standard guidelines.

The final factor is the alcohol by volume (ABV). This value measures the alcohol content of the beer. Irish Stout has an ABV of 4% – 4.5%, according to standard guidelines. However, this value can be up to 6.5% for the Extra Stout category. Guinness typically has an ABV between 4 and 6, implying it falls under the ABV requirements for Irish Stout.

In line with all of these, it is safe to say Guinness is an Irish Stout. Want to know more about Guinness’ nutrition facts? You’ll find all the information on calories, carbs, and more here.

Has Guinness Always Been An Irish Stout?

Interestingly, the Guinness brand as we know it started in 1759 in Ireland by brewing ales. By ales, we mean the traditional light ales popular around that period. However, in 1778, Guinness moved to a type of beer known as porter.

Porter beer was darker in color and was characteristic of London beers. Guinness took the initiative and brought it into Ireland, and the results were fascinating. Technically, the porter beers were called porter stout beers.

However, as time progressed, the Guinness beers were made to be even darker and just called stout. To date, many still argue that the porter and stout beer are basically the same.

Nevertheless, Guinness itself recognizes the beer’s history as moving from ales to porters and then stout. So, to answer the question of Guinness has always been an Irish Stout – no.

Are All Guinness Irish Stouts?

One of the exciting features of the Guinness alcoholic brand is how many different variants and strengths they have. The overwhelming majority of these variants are Irish Stouts. The outlier is the Irish Extra Stout, which is usually made to be stronger in alcohol content and bitterness. The Guinness Irish Extra Stout aimed to cater to foreign audiences.

The two major Guinness variants in the two Irish Beer sub-categories – Irish Stout and Irish Extra Stout – are Guinness Draught and Guinness Extra Stout, respectively.

Enjoy drinking Guinness? Here are 10 other beers like Guinness you should try.

The primary difference between the two is that the Guinness Extra Stout is usually more bitter, with an IBU of 35-50, compared to Guinness Draught’s 25-45. Also, the Extra Stout contains between 5.5%-6.5% ABV, compared to Draught’s 4%-4.5%.

In short, not all Guinness beers are Irish Stouts. Some are Irish Extra Stout. Also, some Guinness drinks are not even ales at all, usually lager or entirely non-alcoholic.