When it comes to the thickness of beer, stouts are often considered to be thicker than porters. This is due to a few factors that contribute to the overall mouthfeel and texture of the beer.
One of the main reasons stouts are thicker is because of the higher amount of residual sugars present in the beer. During the brewing process, the yeast ferments the sugars in the wort, converting them into alcohol and carbon dioxide. However, not all of the sugars are completely fermented, leaving behind some residual sweetness in the beer. Stouts generally have a higher original gravity (OG) than porters, meaning there is a higher concentration of sugars in the wort before fermentation. This results in a thicker and more viscous final product.
In addition to the residual sugars, stouts often contain a higher percentage of unmalted roasted barley compared to porters. This roasted barley adds a distinct bitterness and roasted flavor to the beer. The unmalted barley also contributes to the thickness of the beer, as it contains proteins that can increase the viscosity of the liquid.
Another factor that contributes to the thickness of stouts is the use of specialty malts, such as chocolate malt or black malt. These malts are heavily roasted and add flavors of chocolate, coffee, and roasted grains to the beer. These specialty malts also contribute to the overall body and thickness of the beer.
Furthermore, stouts tend to have a higher alcohol content than porters. This higher alcohol content can contribute to a fuller and heavier mouthfeel. The alcohol can create a warming sensation and add to the overall perception of thickness in the beer.
It's important to note that not all stouts are equally thick, as there are various sub-styles within the stout category. For example, an Irish dry stout like Guinness tends to have a lighter body compared to a Russian imperial stout, which is known for its extremely thick and rich texture.
In my personal experience as a brewer and beer enthusiast, I have found stouts to indeed be thicker than porters. The creamy head, the velvety mouthfeel, and the lingering flavors of roasted coffee and chocolate all contribute to the perception of thickness in stouts.
To summarize, stouts are generally thicker than porters due to their higher residual sugar content, the use of unmalted roasted barley, specialty malts, higher alcohol content, and the specific brewing techniques used to create this style of beer. The combination of these factors results in a rich and thick beer that is often enjoyed for its complex flavors and luxurious mouthfeel.