by David Thompson
The Okinawan sweet potato
photo by Peter French
is dull as a brown paper bag on the outside, but inside, it’s a different story: The flesh is a stunning purple. Equally stunning is the sweet spud’s sudden emergence as the Big Island’s newest cash crop. In the past year, Mainland exports more than doubled, to 100,000 pounds a week. Along the lower Hamakua Coast—where the deep, volcanic soil and ample sun and rain offer perfect growing conditions— farmers are now devoting acreage to it like mad.
The regally colored tuber is believed to have been introduced to Hawaii by contract laborers recruited to work on sugar plantations in the nineteenth century. Plantings surged last year after the U.S. Department of Agriculture allowed farmers to begin zapping their spuds at a Big Island irradiation facility rather than shipping them to a fumigation facility on Oahu, a costly detour. (The treatment step is required to keep Hawaii from accidentally exporting pests such as the West Indian sweetpotato weevil and the sweetpotato stem borer.)
With the popularity of sweet potatoes in general growing—thanks in part to two influential fans, Oprah Winfrey and TV chef Emeril (BAM!) Lagasse—Big Island farmers think the Okinawan variety could get even more popular on the Mainland. No longer just contained to Asian markets, it’s now cropping up in mainstream supermarkets. It’s also appearing in more and more restaurants, as chefs discover its delicately sweet, nutty flavor and the deep, rich color it brings to a plate. Certainly, the tasty purple tuber’s got a lot going for it: Like all sweet potatoes, it’s loaded with vitamins and minerals. Like the blueberry, it is chock-full of antioxidants. And like any potato, it’s wonderfully versatile. Iris Shepard, who has twenty acres of Okinawan sweet potato planted at her farm in Onomea, likes to make purple potato salad, with fruit, nuts and yogurt. "It’s tasty," she says. "Really, really tasty."