Sweet Potato

Ipomoea batatas

Sweet potato is a tropical root crop in the morning glory family, unrelated to the potato despite the shared name. Vaughan and Geissler note that it originated in tropical America and was carried to the West Indies in the sixteenth century, and McGee adds that its subtropical heritage shows in how it is handled and cooked.¹²

In the Northeast, sweet potatoes are a genuinely commercial crop, concentrated in southern New Jersey. Rutgers describes the state’s sweet potato acreage as sitting mostly in the southern half of the state on light, sandy coastal plain soils, with the crop planted only after the soil warms past 65°F and grown at an optimum of 70–85°F.³⁴ New Jersey’s prospective-planting reports have pegged sweet potato acreage around 1,200–1,300 acres, and Hammonton-area growers treat the roots as one of the state’s signature fall crops alongside cranberries.⁵⁶

The food science is what makes sweet potato interesting in a larder notebook. Most varieties sweeten noticeably during cooking because an enzyme breaks starch down into maltose, and moist varieties can convert as much as 75% of their starch that way.² The roots store best at 55–60°F, and chilling injury can cause “hardcore,” a condition where the center stays hard even when cooked.² That sugar load is also why koji-blackened vegetables include sweet potato as a substrate: the long blackening process has plenty of sugar to work with.