The Edinburgh-based novelist recalled how he featured Precious Ramotswe, the leading character in his best-selling No. 1 Ladies’ Detective Agency series, drinking South African red bush tea.
He was later delighted to receive a letter from the biggest producer, thanking him after sales of the drink rocketed around the world.
Speaking on BBC Radio Scotland’s Somewhere Only We Know, to be broadcast tomorrow, he said: “In the first book in the No. 1 Ladies’ Detective Agency series, I had Mama Ramotswe drinking red bush – or rooibos tea as it is also known – and this did have a major impact on the fortunes of the red bush tea producers.
“It was produced at that stage, and still largely is, in a very small area of South Africa in the Cederberg Mountains. It’s not actually tea, but a similar plant.
“I remember receiving a letter a few years after the first book had been published and a number of the subsequent books had appeared, from the main company that produced and exported red bush tea from the Cederbergs. They wrote to me and they said ‘thank you so much for this’. Their sales had gone up by 70 per cent.
“So I was very pleased. I think the books launched the tea in the United States and elsewhere and I am of course delighted about that because it’s produced in a part of southern Africa where there is not necessarily a great deal else that people might be able to do, so it’s an important part of the local economy there.
“And I enjoy it. I drink it as my tea of choice.”
McCall Smith is most widely known for his hugely successful No. 1 Ladies’ Detective Agency series, which is set in Botswana.
He is also famed for his 44 Scotland Street series and The Sunday Philosophy Club series also known as the Isabel Dalhousie Mysteries.
Born and raised in Zimbabwe, he first moved to Scotland to study at Edinburgh University. Although he has settled in Edinburgh since 1984, he also has a Highland retreat on a remote part of the Morvern Peninsula, where he “recharges”.
Speaking from the home, the prolific author describes his remote getaway to presenter Nicola Meighan and reveals how he spends spare time repairing potholes and fishing for mackerel in the loch in front of his house.
He said: “This is a place where certainly I can get away from some of the pressures of my other life. I find, in particular, when I come back here after I’ve been on tour – I do a lot of book tours all over the world – it’s immensely recharging.
“This road belongs to me up as far as the bridge and one of my big hobbies is maintaining the potholes. I come here with my stamper and my spade.”
McCall Smith also describes how he bought an island chain, the Cairns of Coll, in 2014, just to leave it to nature and only visits it once a year.
He said: “When a group of small islands came on to the market north of Coll, called the Cairns of Coll, I was in the fortunate position of being able to acquire those just so that nothing would happen to them.
“These are the most beautiful little islands anywhere on the face of the earth, in my view.”