Raisin harvesting in full swing on Jan Hanekom's Potsepan farm in Upington, South Africa
10 Mar 2020 | Article published in IEG VU Agribusiness
South African raisin and sultana grower covers all bases
Jan Hanekom’s Potsepan farm in Upington, South Africa, uses a combination of air drying and sun drying for its raisins and sultanas crop.
The company finds that sun drying on elevated platforms is particularly effective and it is increasingly moving over to this method.
Conventional sun drying consists of fresh grapes placed either directly onto ground level concrete or on netting, which is then placed on the concrete surface.
The elevated net drying, introduced about five years ago, comprises a raised platform on wooden stakes secured to the ground, and netting on which the fresh grapes are placed to dry out in the sun. This method has the advantage that there is no contamination with soil and any rain that does fall can drip away.
Thompson raisins are produced using these methods.
Jan Hanekom, owner of the farm, explained that the Golden sultanas are air dried on trays in wooden crates which are piled up in the sun outside with a cover over them. This method preserves the distinctive colour of the Goldens as any sun bleaching must be avoided. Hanekom’s farm was averaging about 30 kilos (wet kgs) of sultanas per tray.
The process is known as air drying because this type relies on natural air circulation to dry as opposed to also using the heat of the sun. Typically, it takes 18-21 days until the air dried product is ready for the next stage in the process. In humid conditions, it can take 30 days.
Like the US, South African sultanas are coated in an oil-based solution and dipped in potassium carbonate (potash) and sulphur dioxide prior to drying to speed up the process.
It was also noted that all raisin and sultana farms in South Africa are irrigated under designated water rights. The three methods used are micro, drip and flood irrigation. Costs for irrigated land average USD20,000 per hectare.