During the last centuries BC, long before the development of the Incan empire, the sweet potato was domesticated, and became a staple food for peoples throughout the American tropics, spreading as far north as Mexico and the Caribbean islands. According to Hawaiian and Maori records, the sweet potato was later taken westward to Easter Island and the Hawaiian islands during the 13th century AD, and, in the following century, to New Zealand. It was a match made in botanical heaven, since New Zealand’s soil proved particularly hospitable to the sweet potato. As a result it became the Maoris’ most valuable crop in the pre-contact period.
The first Europeans to encounter sweet potatoes were members of Columbus’ 1492 crew that landed at Hispaniola (the island now shared by Haiti and the Dominican Republic), but the regional varieties cultivated at the time were not sweet at all. Some were starchy and others fi brous. European explorers were only interested in the sweeter varieties and, largely through their efforts, these strains were spread and have flourished, while the others have largely disappeared. Beginning in the early 16th century, sweet potatoes were cultivated in the south of Spain. The plant is easily grown in hot countries from roots or cuttings, but in cooler areas it has to be nurtured in a hothouse.
At the same time Spain was planting its first sweet potatoes, the root veg spread further, arriving first in the Philippines courtesy of Spanish explorers, then as Portuguese traders introduced it to India and the Dutch East Indies. By the end of the 16th century the sweet potato fi nally arrived in China. In 1593, a famine in Fujian province forced the governor to send an expedition to the Philippines in search of a new food crop. The following year, the ships returned carrying sweet potatoes. China now leads world production, almost half of it used for feeding livestock.
The sweet potato was likely introduced to Africa via slave traders. Since then, the crop has been steadily nudging out the yam as a major carbohydrate staple in tropical Africa. And speaking of yams, the terms “yam” and “sweet potato” are often used interchangeably. This is incorrect, as the two plants are unrelated; American farmers and retailers started the confusion about a century ago when they began selling sweet potatoes as yams. It’s easiest to
differentiate the two by the rougher, bark-like skin of the yam, which, as the tuber of a tropical vine, also shows a greater variance in size.
North American Indians have long grown sweet potatoes in the warm climates of the American southeast, especially in Louisiana, where de Soto discovered them in 1540. During both the U.S. Civil War and the Revolutionary War against the British, sweet potatoes were highly prized for their ability to mature rapidly and flourish underground—making them less vulnerable to the deliberate destruction of war than surface crops.
Sweet potatoes are usually baked, broiled or boiled in their skins, or fried. They can be incorporated into breads and cakes; sweetened, spiced and used in pies; or made into chips. In New Zealand, sweet potato’s long history makes it a natural choice for creative culinary interpretations such as this decadent, creamy and easy-to-make risotto.
Sweet Potato Risotto
Traditionally, this creamy Italian rice dish requires liquid to be added gradually and stirred constantly—rather labour-intensive for today’s time-deprived home cooks. In this version, the rice is stirred only when the sweet potato is added. Serve as a first course, main dish or side dish with grilled meats or fish.
- 2 tbsp olive oil
- 1 onion, chopped
- 2 cloves garlic, minced
- 1 1/2 cups short-grained Italian rice such as arborio
- 4 cups chicken broth
- 1 tbsp white wine vinegar
- 1 tsp dried sage
- 1/2 tsp salt
- 1/2 tsp dried thyme
- 1/4 tsp ground black pepper
- 4 cups large, bite-size pieces peeled sweet potato
- 1/2 cup light or half-and-half cream
- 1/2 cup grated Parmesan cheese
- 1/4 cup minced fresh parsley (optional)
- In large saucepan, heat oil over medium heat. Cook onion and garlic, stirring for 2 to 3 minutes. Add rice. Cook, stirring, for 2 to 3 minutes.
- Stir in chicken broth, vinegar, seasonings. Bring to a boil.
- Cover and reduce heat to medium-low. Cook for 5 minutes. Stir in sweet potato. Simmer for 15 to 18 minutes or until sweet potato and rice are tender but still slightly fi rm.
- 4. Stir in cream (rice should be moist and creamy). Serve immediately topped with cheese and parsley. (If rice becomes dry after standing, add a little more chicken broth). For a variation, add diced cooked bacon or smoked sausage.