Oct 12, 2021

Sweet potatoes: Proper curing improves quality, shelf life

Sweet potatoes are not very sweet when they are initially harvested, Shaun Francis, Extension horticulture specialist for the University of Arkansas at Pine Bluff, said. Farmers should cure their sweet potato crop for a period of time to enhance the taste and ensure a longer shelf life.

“Sweet potatoes remain metabolically active after they are harvested,” Francis said. “As the tubers continue the respiration process, their starches are converted to sugars, hence the sweet taste. Curing improves this conversion process.”

Another purpose of the curing process is to heal any abrasions or bruises the sweet potatoes sustain during harvesting, he said. As the potatoes cure, a corky layer of cells develops just below the surface of the abrasions, which serves as a barrier against disease-carrying organisms and protects against storage diseases.

The curing process can begin immediately after sweet potatoes are harvested. First, they should be removed from the field as soon as possible to prevent sun-scald damage.

“If you are harvesting during moist conditions, allow the soil around the roots to dry for an hour or two,” Francis said. “Though you can remove excess soil around the roots, remember not to wash your freshly harvested potatoes.”

Store the potatoes in a warm, humid room for four to seven days. Ideal conditions for curing are a temperature of 85–90 degrees and a relative humidity of 80-90%.

“As these conditions may be difficult to establish inside a household, consider using a shed at the farm or a garage,” Francis said. “Some farmers can achieve the correct conditions for curing in a room with a space heater, thermostat and humidifier.”

If the temperature decreases during the curing process, increase the number of days the sweet potatoes spend curing. If it is 80 degrees outside, let the potatoes cure for 10 to 14 days, he said.

Good ventilation is also an important factor in the curing process, as it can prevent a buildup of the carbon dioxide that is released by the tubers. The circulation of air also enables excess condensation to escape, which prevents rotting.

After sweet potatoes have been cured for the correct amount of time, they should be stored at temperatures around 55-60 degrees and a relative humidity range of 85-90%, Francis said.

“Keep the storing conditions at a constant, as fluctuations will cause the deterioration of root quality,” he said. “Low temperatures cause the potatoes to develop too tough a center, while high temperatures will cause the roots to sprout, shrivel and become pithy.”

Francis said sweet potatoes stored in cool, constant conditions have a shelf life of up to several months.

For more information about sweet potato production or other horticulture topics, contact Francis at (870) 575-7224 or [email protected].

– Debbie Archer, University of Arkansas at Pine Blueff