Honestly, it’s hard to say. Some people say that a porter has chocolate malt, and a stout has roasted barley. But if you dig into that even a little bit, you’ll find that it doesn’t hold true. Generally, if a brewery has both, the stout’s probably bigger. That’s because the original name for “stout” was “stout porter,” as in “a big-ass version of a porter.” Porter, by the way, was named after the big burly guys who carried things around London, and were big fans of the beer back in the 17th and 18th centuries (you could also probably describe them as stout, come to think of it.”

The BJCP, the high priests of beer orthodoxy, describe 8 types of stouts and 4 types of porters. They all vary slightly in strength, color, and ingredients, but largely overlap. Really, it’s like the Supreme Court definition of smut – you’ll know it when you see it (and you’ll probably like it either way).