How and Why Sweet Potatoes are Cured
Within one to two hours of harvest, the sweet potatoes are taken to storage where they are cured for 4 to 7 days at 80 to 85 degrees with a relative humidity in the 90 - 95% range. Ample ventilation is also necessary at this time. During this early curing process, sweet potatoes rapidly heal any cuts, bruises or skinned areas that may occur during harvest. The actual act of curing allows the periderm to thicken and to reform. Curing also converts some starches to sugars which enhance the flavor of the sweet potato.
Sweet potatoes are normally stored in bulk containers that hold from 20 to 40 bushels.
A small portion (15 to 20 %) of the marketable roots are washed, graded, and packed within a few days of harvest and immediately shipped to the buyers. Such roots are referred to as “fresh” and are usually not as sweet as cured sweet potatoes.
A leader in innovation, Wayne E. Bailey Produce Co. installed the Southeast’s first special storage units to hold the sweet potato crop. Efficiencies in overcoming weight loss (shrinkage) have been significant because of special techniques used.
WEB was one of the first growers in the state to use forced-air cooling to further cure and sweet potatoes at 55 to 60 degrees with 85 percent relative humidity. In this horizontal ventilation system, bin boxes are stacked allowing air to pass through keeping the sweet potatoes cool and moist, while creating more flavor and allowing for year-round shipping.
Properly cured and stored sweet potatoes can be held up to 12 months with little reduction in quality. Shrinkage occurs at 1 to 2 % per month if cured, 2 to 5 % if uncured.