They ship molasses around the world – and in Belfast, their forebear made a lasting contribution to everyone's well-being when he bequeathed his house and its grounds to the city.
Nearly 70 years later, William Barnett's descendants at W&R Barnett are still running what has become Northern Ireland's biggest manufacturer of animal feed stuffs, with turnover of £500m in the group.
Many of its businesses are jointly owned with Origin Enterprises plc, and it has been in a joint venture with R&H Hall since the 1940s. W&R Barnett also owns animal feed company, Thompsons.
The Barnett family, William, (37) and his father Robert (69) are among the province's most remarkable business people.
They don't court publicity or seek to trade on the illustrious, philanthropic history of their family and the company, which was founded in 1896.
They are rarely photographed – though portraits of Robert Barnett and his father William hang in the Belfast Harbour Office, commemorating their chairmanship of the Belfast Harbour Commission.
But the name Barnett is indelibly linked with Belfast, and we have a reason beyond the purely economical to be grateful for their prowess in business.
In 1946, an earlier William Barnett, the co-founder of the company, bequeathed his house and grounds close to Shaws Bridge in the south of the city to Belfast Corporation.
He was also a keen horse breeder, and his horse, Trigo, was the winner of the 1929 Derby.
While the house is now known as Malone House, the grounds are still known as Barnett Demesne.
So the Barnett name will always endure – though it continues to resound in business as the family firm goes from strength to strength, particularly following the £71m acquisition of United Molasses from Tate and Lyle four years ago.
Economist, John Simpson, who compiles the Belfast Telegraph's annual Top 100 Companies countdown, has followed the growth of the Barnett empire for decades.
He described it as "one of the most profitable and successful family-controlled businesses" in Northern Ireland.
The business enjoyed "record levels" of turnover in the year to July 2013, when revenues grew to just under £500m.
"In the last five years the Barnett group of companies saw business more than treble," he said.
He points out that the group operates its own dockside facilities, and still retains an interest in horseracing.
The overall group results include trading figures for 26 active subsidiaries – 14 registered in other countries where they trade in the marketing of molasses – and seven other associated companies.
Mr Simpson said pre-tax profits were up £.16m to £22.3m, while employment increased from 256 to 278. He added: "The group has expanded its business successfully, with only a relatively modest increase in borrowed funding. In the last three years, the capital programme has been eased by the retention of significant post-tax profits in the business and bank borrowing outstanding in July 2013 of just over £40m."
The family never gives interviews – though Robert Barnett did speak to Alf McCreary for his book, Titanic Port (see panel).
The year to July 2013 was probably their most successful yet, and the acquisition of Advanced Liquid Feeds in February 2013 by United Molasses Group had added £32.9m to turnover.
Sharply increasing raw materials prices for feed grains and related agricultural commodities also contributed to rising profits.
There's no doubt that they have been able to benefit from the overall success of the agri-food sector in the province.
But the acquisition of United Molasses marked a turning point for the business, as it started to look far, far beyond Northern Ireland.
Now, United Molasses accounts for over 50% of reported group turnover, and the acquisition was one of the biggest in Northern Ireland history.
That has made W&R Barnett a global trader, and active in Western Europe, Asia and Central America. It is now buying, shipping and selling vessels of molasses around the world for use in yeast, rum, lysine, mono-sodium glutamate and steel production.
The company believes United Molasses has given it opportunities to grow over the last three years, and is likely to continue to do so.
But quiet and steady growth has been the defining characteristic of company strategy in this most private of family firms.
They're expected to continue to grow in a sensible and controlled manner.
That could mean continued growth and investment in their present assets, or even more acquisitions – but whether they'll be as big and bold as United Molasses remains to be seen.
'The port has always been in my blood'
"I SUPPOSE the port has always been my blood, just like the horses." Robert Barnett is chairman of W&R Barnett, and the father of BHH chairman, William Barnett. Robert was interviewed by journalist and author, Alf McCreary, for his book, Titanic Port: An Illustrated History of Belfast Harbour.
Robert was chairman of the board of the Belfast Harbour from 1993 to 1998, following his father William H Barnett's chairmanship between 1972 and 1980, and he shared rare insights into the driving force of the business with Mr McCreary.
According to Titanic Port, the family started out as farmers in Templepatrick and set up their first silos at the harbour in 1937. After the war, they entered into a joint venture with another grain company, R&H Hall. William Barnett, the company co-founder, was a well-known horse-breeder who owned Trigo, which won the derby in 1929. According to Mr McCreary, "industrial relations throughout the harbour were never better than when the Barnett stables were on a winning streak".
And Robert has continued the family's involvement in horse-breeding, telling Mr McCreary: "The dockers have always taken an interest in this, and I think it helps, because people feel that if you are involved in horses, you must be a real human being."
Mr Barnett added: "There are certain similarities between our business and our horse breeding. Both are high-risk ventures, and things don't always go the way one would like." He told Mr McCreary: "I have always enjoyed working at the port. I've loved the atmosphere, and the bustle in the old days when the dockers were doing difficult and often dangerous jobs. I also like ships, and even the pictures of ships. I suppose the port has always been in my blood, just like the horses."