IN SOUTH AFRICA’S wine lands, the oldest in the new world, the whitewashed homes of early Dutch settlers in the Cape have been transformed into sleek tasting rooms with views of the valleys and vineyards. On many estates stands a slave bell, once rung for the start and end of the working day in the fields, now a memorial to the men and women who toiled away and a backdrop for tourist photographs.

Some of today’s workers are the descendants of those slaves. Many are still poor and live in shacks; farmworkers in the Cape are among the country’s lowest-paid. Nearly all the farm owners are white, the workers brown or black. Tourists can sip a sundowner in the quaint wine-lands town of Franschhoek as lorries rumble down the main street, loaded with low-paid men being delivered home after a day’s work.

This lack of social and economic change is one of South Africa’s most intractable problems, and a source of growing frustration. Last year it exploded in the country’s mining belt near Johannesburg. More recently, violent demonstrations have occurred almost every day in the wine- and fruit-growing region of Western Cape province, with police firing rubber bullets at stone-throwing protesters who blocked the country’s main north-south road.

Though some of the protesters are unemployed criminals taking advantage of the lawlessness, most of them sorely want to improve their poor conditions. The latest protests have centred on the grape-growing area around the town of De Doorns. Workers are demanding a daily wage of 150 rand (about $16), more than double the government-set minimum of 69 rand a day for farm workers. They also want better living conditions. Some describe their dwellings as rat-infested hellholes, without toilets, running water or electricity. In a report in 2011 Human Rights Watch, an international lobby, documented workers’ exposure to toxic pesticides.

The Congress of South African Trade Unions (Cosatu), the labour federation allied to the ruling African National Congress, has threatened to call for a worldwide boycott of South Africa’s fruit and wine, citing “slave labour conditions”. But farmers say they are losing money and cannot afford to pay more. A boycott would devastate a big chunk of the country’s farming and cause job losses at a time when nearly 40% of workers, by some measures, are already out of work. Even more job losses are likely as farmers increasingly mechanise.

Some wineries have shown how it can all be done differently, getting ethical-trade certificates. Solms-Delta, an estate near Franschhoek, is run as a trust with workers and their families, many of them descendants of slaves, now owning a one-third stake. They are trained to work at other levels of the business, not just in the fields. A restaurant on the estate serves indigenous “Cape cuisine”, influenced by the spicy food of the Malay slaves, as well as ingredients used by the Khoi people (formerly known as Hottentots) who lived in the valley thousands of years ago.