Among Adam Smith’s friends in Glasgow, where Smith was both student and later, Professor, was Joseph Black, whose father was a resident Scottish wine négociant in Bordeaux.

At the time, Baron Montesquieu, was active in the Bordeaux ‘parliament’. Though a Monarchist, he was the author of ‘The Spirit of the Laws’ (De l’Esprit des Lois, 1748), still the classic account of the evolution of law and the need for the constitutional ‘separation of powers’ (legislature, executive and judiciary), which operates today, if sometimes imperfectly (e.g., the UK), in secular democracies, but not in dictatorships.
There is a direct connection between Bordeaux and Scotland and not just in the importation of wine (‘claret’), but also in Baron Montesquieu’s ideas. Smith, among many others, used them extensively in his own writings and he translated sections of The Spirit of the Laws in articles he published in the Edinburgh Review.

When he visited Bordeaux twice in 1764-66 he had introductions to several wine producers, almost certainly from the father of his close friend, Joseph Black. Given what we know of Smith’s diligence as an observer, he would have paid close attention to wine making and its economics. He would have walked the vineyards with his pupil, the Duke of Buccleugh, and listened closely to the local experts regarding every aspect of wine growing, production and marketing.

Joseph Black was a life-long friend of Adam Smith, he became a professor of chemistry in Glasgow and later at Edinburgh, and was appointed an Executor of Adam Smith’s Will. Close contact with Joseph Black accounts for Adam Smith’s knowledge of the wine trade through regular contact and exchanges with Joseph’s father and from his visits to Bordeaux – and it seems from a taste for the region’s finest products.