Japanese sweet potatoes range in size from medium to big and have cylindrical, oblong, and slightly bulbous shapes with rounded to tapered ends. The textured skin is smooth and semi-rough, with a few shallow eyes and a colour range of pink, red, purple, and light brown with a red undertone. The flesh is firm and dense when raw, with a creamy white to pale yellow tint that deepens to a golden yellow and develops a softer feel when cooked. Japanese sweet potatoes have a drier, starchier texture than other sweet potato cultivars with a mildly sweet, nutty, flowery, chestnut-like flavour. Japanese sweet potatoes, botanically known as Ipomoea batatas, are the dry-fleshed root that grows on sprawling vines and belongs to the Convolvulaceae (morning glory) family. Japanese sweet potatoes, also known as Oriental sweet potatoes and Japanese yams in the United States, are a generic term for types with red-purple skin and white meat. These kinds, which originated in Asia, have gradually gained favour in North America as people understand the root's antioxidant-rich benefits. With increased demand, American breeders are generating superior Japanese varieties with extended storage capacities, disease resistance, and greater flavour to create a year-round supply. Common regional names for these potatoes include Kotobuki, Murasaki, and Boniato, but the roots are often branded generically as Japanese sweet potatoes in various markets.
Flavour profile of Japanese sweet potatoes
Compared to other sweet potatoes, Japanese sweet potatoes have a concentrated, natural sweetness that is earthier and nuttier. Due to their starchiness and low moisture content, they also have a lighter and fluffier texture.
Culinary applications
In almost every recipe or application, such as steaming, boiling, roasting, frying, mashing, and pureeing, Japanese sweet potatoes can be substituted for orange-fleshed sweet potatoes. They make great sweet potato fries and can be baked whole or in casseroles and gratins. They're also great chopped into cubes, rounds, or chunks and baked since they keep their shape. Because of the texture change, you may want to add a little extra moisture to a recipe that would normally be made with softer sweet potatoes to create a smooth texture, such as adding a little more liquid to a pureed sweet potato soup.
Storage
When stored properly, Japanese sweet potatoes can last for up to a month. Japanese sweet potatoes will sprout if exposed to light, so store them in a cool, dark, dry place, such as a closed pantry or cupboard. Avoid storing sweet potatoes in the refrigerator, and avoid washing them before storage because introducing moisture to the skins can cause them to decay prematurely.