What is the Difference Between a Porter and a Stout?

One of the biggest mysteries in the beer world: what is the difference between a porter and a stout? At first glance, they are seemingly interchangeable; dark beers with a nice foamy head. To the average palate, they even taste similar. The porter may seem a bit lighter and sweeter, but the difference can be hard to detect. So what is it then that sets these two apart? The answer, it seems, is not so black and white. Instead, you have to go back in history to the 18^th century. According to A General Dictionary of Commerce, Trade, and Manufacturers, published in 1810, "Porter may be divided into two classes, namely brown-stout and porter properly so called… Brown-stout is only a fuller-bodied kind of porter than that which serves for ordinary drinking." Simply put, back in the day, a brown-stout was just a stronger porter. The Beer Connoisseur has a fantastic article on the full history of porters and stouts, but we are going to attempt to summarize it for you:

• In the 18^th century, brown-stout was the name for a strong porter, because stout simply meant "strong" beer, and one could still find pale stouts during that time.
• The arrival of patent malt in 1817 changed the way many breweries brewed porters, since it could now be brewed cheaper using all pale malt. Some breweries began using only pale malt, while some used a mixture of pale, brown, and roast malts for their stouts and porters.
• In 1844, Whitebread, one of the top London porter breweries, was making 5 different types of dark beer: a porter, a keeping porter, a single stout, a double stout, and a triple stout. Their brewing books show that they were using a ratio of ¾ pale malt to ¼ brown malt for both their porters and stouts, but they were making one strong mash for the stouts, and then using that same mash a second time to create their porters. Therefore, due to the re-used mash to make the porters, the stouts were coming out stronger than the porters, which was the only difference between the two.
• The legalization of roasted barley as an ingredient in beer in 1880 began to change porters and stouts slowly but surely. While some breweries jumped on the roasted barley train, many others were adamant that the flavor of roasted barley was "inferior."

So how does this history lesson play into the different porters and stouts we see now? Well between the 1800's and the craft brewery revolution that began in the 1970's, there was hundreds of years worth of different brewing recipes for both porters and stouts. These recipes all varied in their pale and brown malt ratios, as well as their roasted barley use. Therefore, breweries in the 1970's had thousands of different recipes that had been created over the years to try and replicate, further muddling the hard distinction between porters and stouts. Bottom line? Now a days, porters and stouts are whatever you want them to be. They are both dark, delicious beers, and each brewer can put their own unique spin on them, and label them as whatever the heck they want. And so the mystery continues…