地瓜球Sweet Potato Balls

Sweet potatoes are peeled, steamed and mashed while hot, then thoroughly mixed with tapioca starch (recipes differ: some use or add sweet potato starch, potato starch or glutinous rice flour, plus sugar), kneaded into a dough and rolled into small balls. The choice and proportion of starches is each stall's own secret: sweet potato starch adds chew, but too much dries the dough and the fried balls turn hard.

Once in the oil, the balls are first left to set, then pressed again and again with a ladle. Each press squeezes out the oil they have soaked up and lets air in, so the balls swell into hollow spheres with a crisp shell and a chewy lining. They are crispest straight from the fryer; as the shell meets moisture in the air it softens and can collapse, so they are best eaten fresh.

The sweet potato ball has no reliably documented date, but the sweet potato itself has a long story in Taiwan. It is thought to have come from Fujian in the late 16th century, the scholar Chen Di noted Indigenous people growing it in 1603, and by the 1700s it was a key crop. Poorer households ate it as porridge or soup, while better-off ones steamed it with rice to stretch the grain. In the 1950s and 1960s it was grown mostly as pig feed, peaking at about 3.7 million tonnes in 1969 before falling sharply as feed shifted to corn.

Two stories circulate about the snack's origin. In one, a retired man grew sweet potatoes under a bridge (a Supertaste report names Zhongzheng Bridge in New Taipei); when river-bank works dug up his field, he fried the tubers rather than waste them, and the recipe was refined into the sweet potato ball. In the other, the snack was inspired by deep-fried sesame balls (English Wikipedia cites Clarissa Wei's 2023 book Made in Taiwan for both). Both are hearsay with no original documents behind them.