Machine Production of Sweet Potato Balls: Dividing, Rounding, and Freezing

Sweet potato balls (地瓜球, also called QQ balls) are a popular item at night markets and snack stalls. As they fry, they are pressed and turned, so the outside becomes hollow and crispy while the inside stays chewy. To fry them nicely, every ball must be the same size: big ones have not puffed yet when small ones are already overdone. This is also why many stall operators and frozen food businesses have started dividing by machine.

What Machine Divides Sweet Potato Balls?

Sweet potato ball dough is similar to taro ball dough: cooked sweet potato paste plus sweet potato starch or tapioca starch, with sugar, kneaded into a dough. The machine dividing method is the same too: a dividing machine extrudes the dough into a rope of fixed thickness and cuts it into sections by length, so every section weighs the same.

Dong-Yih Machinery's website lists two models that can make sweet potato balls:

• DY-528MS Taro Ball and Sweet Potato Ball Dividing Machine: 3,000–12,000 pieces/hour, 10 g–30 g per piece or heavier, single-phase 220V, 1.6 kW (three-phase 380V/415V/440V must be custom-ordered). Suitable products also include sweet potato balls (蕃薯圓), taro balls, mochi, various fillings, and rice cakes.
• DY-528M Automatic Dough and Filling Dividing Machine: Same output and weight per piece as above; suitable products are sweet potato balls, mooncake filling, mung bean paste, red bean paste, sun cake filling, Dajia pastry filling, taro pastry filling, and dividing cookie dough bars.

The two differ in the range of suitable products, so you can choose based on what other products you also need to make.

How Are the Pieces Rounded After Dividing?

A dividing machine cuts short pieces, and sweet potato balls need to be round to fry evenly. Common methods:

• Rolling by hand: The most straightforward for small-scale production. Since the dividing machine has already fixed the size, rolling is just shaping, much faster than portioning from scratch.
• Rounding equipment: A drum or rotating disc tumbles the pieces into balls. Dusting is usually needed during rounding to keep them from sticking together.

The firmness of the dough affects rounding: too soft and they flatten and stick together; too firm and the surface cracks, making them prone to bursting during frying.

Dough Recipe and Machine Performance

• Water content of the sweet potato: Yellow-fleshed and red-fleshed sweet potatoes differ in water content, and the steaming method also changes it. It is best to judge the recipe by "the state of the kneaded dough" rather than sticking rigidly to proportions.
• Type of starch: Sweet potato starch and tapioca starch give different textures, and some recipes mix the two.
• Sugar: More sugar browns more easily and also makes the dough stickier.
• Knead until smooth: If the dough has cracks or dry flour, the cut faces will not be smooth after extrusion.

Should They Be Frozen Before Frying?

It depends on how you sell them:

• Made to order: If a stall divides and fries on the same day, freezing is not necessary, but the divided raw balls should be dusted and covered to keep the surface from drying out or sticking together.
• Frozen semi-finished products: For wholesale to stalls or sale as frozen food, divide and round them, dust them, spread them out flat to blast freeze, and then bag them. Freezing sets their shape so they do not stick together and extends shelf life. For frozen transport, under Article 8 of the Regulations on Good Hygiene Practice for Food (食品良好衛生規範準則), the ambient temperature of frozen compartments must not be higher than -12°C.

Whether frozen sweet potato balls need thawing before frying depends on the recipe and frying method. A common approach is to put them straight from the freezer into medium-low temperature oil, and once they float and soften, start pressing them to make them puff; after thawing, the surface becomes wet and sticky and is more likely to stick to the pan.

Cleaning and Safety

Sweet potato paste contains sugar and starch, and residue on the extrusion outlet and cutter quickly turns sour and moldy. Disassemble and wash them at the end of every day. Before disassembly, stop the machine, cut the power, and apply lockout/tagout; this is the basic requirement of Article 57 of the Occupational Safety and Health Facilities Regulations (職業安全衛生設施規則) for cleaning, inspecting, and adjusting machinery.

For taro balls, see Machine Production of Taro Balls and Sweet Potato Balls. To find out whether the DY-528MS or DY-528M is right for you, call 06-257-4644 or ask through our Contact page.

FAQ

Q: How many sweet potato balls can a dividing machine make per hour?
A: Dong-Yih's website lists the DY-528MS and DY-528M at 3,000–12,000 pieces/hour, at 10 g–30 g per piece or heavier.

Q: Does a dividing machine make round balls directly?
A: A dividing machine cuts short pieces; for round balls, they need to be rolled by hand or run through rounding equipment.

Q: Should sweet potato balls be frozen before frying?
A: Made-to-order frying does not require freezing; frozen semi-finished products for sale must be blast frozen. Frozen sweet potato balls are commonly put straight into medium-low temperature oil without thawing.

Q: What is the difference between the DY-528MS and DY-528M?
A: Output and weight per piece are the same; the difference is in the suitable products listed on our website: the DY-528MS adds taro balls, sweet potato balls (蕃薯圓), mochi, Ningbo rice cakes, Korean rice cakes, and more.

Q: What should I do if the sweet potato ball dough is too sticky?
A: Usually the sweet potato is too wet or there is not enough starch. Add more sweet potato starch or tapioca starch and knead until smooth and no longer sticky before running it on the machine.