By 1726 porters where very popular in London with the workers moving to London at the beginning of the industrial revolution. Those workers were called porters and so the beer got its name.
In the 1770s brewers changed to using mostly pale malt with some brown malt. Customers thought people were watering down their porter when that happened, so some brewers started adding stuff like opium and hemp to shut them up LOL.
By 1780 porter brewing was a massive industry in England.
Daniel Wheeler invented the malt roasting drum in 1817 and black patent malt was able to be made, thus solving the problem. 90% pale male and 10% black patent malt.
Modern-day Robust porter uses black patent malt. Modern-day brown porter does not.
Brown porter is supposed to have toast and nutty flavours with some caramel. Little or no hop flavour. Slight roastiness and a balance that ranges from slightly malty to slightly bitter.
Fuller’s London Porter is supposed to be a good example. I found some at the NSLC. Not tasted it yet.
