My mother-in-law, Nan, likes to buy Louisiana sweet potatoes direct from a local farmer, resulting in a large box of spuds that get passed around among my husband’s large extended family. We’ve been well-plied with Beauregard variety sweet potatoes for several weeks now, and each time I go back to the till for more, she repeats the same directive: Keep the dirt on them until you cook them.
Is this true, or just rural myth? I recently asked LSU AgCenter Associate Professor Tara Smith, who studies the Louisiana sweet potato at the state’s research station in Chase, Louisiana, southeast of Monroe. The dirt, Smith says, keeps the sweet potatoes from bruising before use.
“Sweet potatoes are stored with the dirt on them after harvest. They’re not washed until they’re packed and shipped to market,” she says. “If you buy direct from a producer with the dirt on them you can store them in that manner until you’re ready to use them. Really, it is the handling component. They are susceptible to bruising and the more they are handled the more likely you are to encounter losses due to shriveling, bruising and subsequent breakdown.”
So there you go.
The dirt is a sort of protective layer for Louisiana’s favorite vegetable.
And what about curing?
Unlike other fresh picked produce, sweet potatoes have to “set up” before they’re ready to consume, or so they say. True? Yep. Consumers never really see this stage, though. Smith says that sweet potatoes are cured immediately following harvest, a process that involves bringing them into the storage shed and subjecting them to 85-90 degrees F and 90% humidity for 5-7 days. Potato sauna! Afterwards they’re stored at 55-60 degrees also with high humidity. After about 6 weeks they’re ready to be packed and shipped. The curing process quickens the conversion of starches into sugar and makes the spud tastes sweeter. It also begins the healing process of any bruises and skinning that occurred during the harvest operation, and “sets” the skin, allowing the sweet potatoes to be washed and packed with less damage to the outer surface.
As for shelf life?
Sweet potatoes can be stored for a year or longer under the right conditions, making them seasonal in Louisiana year round.