That is a very good description of stout flvaour(s) in the 1800's. It's funny but the version of Guinness Stout brewed in Canada under license tastes quite like circa-1850 Guinness. It is very fizzy with a chalky, tart flvaour. This Guinness is made I understand by adding a concentrate of some kind from Dublin to a base beer made here. While seemingly a lesser version of Guinness (we get all the others too except FES and 250th), it is actually pretty good and is similar to the bottled Guinness I recall in the U.K. in the 1980's.The term "nut" as applied to brown ale in the poems was intended simply to emphasize its colour. Oddly though, while (as I recall) nut brown draughts were lauded as country drinks - e.g., by Oliver Goldsmith - it was not generally a country style of beer. I think the answer must be that the poets were city-based or inclined, and used a London beer style to evoke lyrically aspects of the country. Poetic, not brewer's, license.Gary