Hoshi Imo is a classic fall snack in Japan, allowing you to enjoy the natural sweetness of Japanese sweet potatoes. Its rich, concentrated flavor will leave you craving more with every bite.
Wash the sweet potato thoroughly to remove any dirt. Fill a steamer with water and heat it until it boils. Once boiling, add the sweet potato and steam it for about an hour. Alternatively, you can boil it for about an hour.
Remove the sweet potato from the steamer. Trim both ends and peel off the skin along with any brown parts inside. Cut it into your preferred size, about ⅓ inch (7-10 mm) thick.* I cut the sweet potato into bite-sized pieces, but you can also keep its natural shape by cutting it into large vertical slices, or cut it into easy-to-eat sticks—as long as each piece is about ⅓ inch (7-10 mm) thick.
Spread the sweet potato pieces on a wire rack or bamboo colander, making sure they don't overlap. Let them dry in the sun for 2 or more consecutive sunny days. Once they reach your desired level of firmness, they are ready to enjoy.Note: Store the pieces at night in a cool, well-ventilated place to prevent mold growth. Drying for 2 days results in a slightly softer texture (recommended), while drying for 3-5 days yields a firmer texture. If you want to keep insects away from the pieces, cover them with a net or similar material.
Notes
If you dry your sweet potato pieces in the sun for 2 days, you can store your hoshi imo in an airtight container in the refrigerator for up to 4 days. Drying them in the sun for 5 days will allow the hoshi imo to last for up to a week.