Machine Production of Mantou, Flower Rolls, Silver Thread Rolls, and Gua Bao

Mantou (饅頭), flower rolls (花捲), silver thread rolls (銀絲捲), and gua bao (割包) are all fermented flour foods, but their shapes differ a great deal, and so do the machine methods. Sorting them by shape first makes it easier to decide which equipment you need.

Do Mantou Need a Dividing Machine or a Forming Machine?

Depending on shape, mantou are made in roughly three ways:

• Round mantou (hand-kneaded mantou): The dough is divided into portions and rounded. This can be done with a divider-rounder, or with an encrusting and forming machine running "without filling" to cut round balls directly.
• Knife-cut mantou (square mantou): The dough is sheeted, rolled into a log, and cut into sections, using a dough sheeter with log-rolling and cutting equipment.
• Filled mantou and two-color mantou: To wrap one dough inside another or create a two-color pattern, you need an encrusting and forming machine or a dedicated mechanism.

So "divider or forming machine" depends on the shape you want. If you only make plain mantou, dividing and rounding is enough; for more varied products, an encrusting and forming machine offers more flexibility.

The products listed on Dong-Yih Machinery's website for the DY-201 Automatic Steamed Bun and Mantou Machine related to mantou include scallion rolls, two-color mantou, mini mantou, and longevity peach buns, and it can also produce silver thread rolls, gua bao, and silver thread flower rolls, with an output of 2,000–12,000 pieces/hour at 2.0 kW.

How Are Two-Color Mantou Made?

The common handmade method for two-color mantou is to layer white dough with colored dough (brown sugar, cocoa, red yeast rice, pumpkin, taro, etc.), roll them up, and cut into sections so a spiral pattern appears on the cut face. Machines follow a similar idea:

• Co-extrusion: Using the encrusting machine principle, one dough is fed as the outer layer and the other as the "filling," so after cutting the outside is white and the inside colored, or a pattern is created depending on the nozzle design.
• Layer-and-roll: The two doughs are sheeted separately, layered, rolled up, and cut into sections.

The two doughs need to be similarly firm, or the proportions will drift during extrusion and the pattern will distort. Doughs with added vegetable purée or cocoa powder absorb water differently, so their recipes must be adjusted separately.

Flower Rolls and Scallion Rolls

Flower rolls are made by brushing a dough sheet with oil, sprinkling it with scallions or other toppings, rolling it up, cutting it into sections, and twisting them into shape. The keys on a machine are:

• Oil and toppings must be applied evenly; too much makes the dough layers slide apart so they cannot be twisted together.
• The twisting motion is mostly done by a dedicated mechanism, or the sections are shaped by hand after cutting.

The bread-making peripherals on RHEON's Japanese website include a "twister" (ツイスター, twist-forming machine), which shows that twist forming can be mechanized; however, each manufacturer's twisting method and resulting appearance differ, so you need to see the actual machine.

Can Silver Thread Rolls Be Made by Machine?

Silver thread rolls are made by cutting dough into fine strands (the "silver threads"), oiling them, and wrapping them in a sheet of dough. After steaming, peeling back the outer layer reveals strand after strand of noodles inside. The difficulty is that "the fine strands must not clump together":

• The strands need to be sheeted and cut, then oiled evenly.
• The outer wrapper must wrap them tightly without flattening the strands inside.

Dong-Yih's website lists silver thread rolls and silver thread flower rolls among the products the DY-201 "can also produce." For the actual fineness of the strands and the thickness of the wrapper, we recommend bringing your recipe for a test run.

Gua Bao (刈包)

Gua bao is an oval dough sheet brushed with oil and folded in half, which can be opened up after steaming to add fillings. The machine method is usually: sheet the dough → cut oval pieces → oil (or brush with a thin layer of oil) → fold in half → pan and proof. Oiling is the key to letting the fold separate after steaming; too little oil and it sticks shut, too much and the edges slide apart. Dong-Yih's website also lists gua bao among the products the DY-201 can also produce.

Common Points to Watch

• The temperature of fermented dough must be stable, or earlier and later batches will vary in size.
• The capacity of final proofing and steaming after forming is often the bottleneck of the line.
• When cleaning and maintaining, stop the machine and cut the power. Article 57 of the Occupational Safety and Health Facilities Regulations (職業安全衛生設施規則) requires that machinery be stopped, locked out, and tagged when it is cleaned, oiled, inspected, repaired, or adjusted.

For steamed buns, see Machine Production of Steamed Buns. To confirm whether the DY-201 can make the mantou or silver thread rolls you want, call 06-257-4644 or ask through our Contact page.

FAQ

Q: Do I need an encrusting machine if I only make plain mantou?
A: Not necessarily. Round mantou can be made with dividing and rounding equipment, and knife-cut mantou with sheeting, log-rolling, and cutting. An encrusting and forming machine becomes more necessary when making filled or two-color mantou.

Q: Can two-color mantou be made by machine?
A: Yes, commonly by either co-extrusion or layer-and-roll. Dong-Yih's website lists two-color mantou for the DY-201. The two doughs should be similarly firm.

Q: Can silver thread rolls be made by machine?
A: Dong-Yih's website lists silver thread rolls and silver thread flower rolls among the products the DY-201 can also produce. For strand thickness and wrapper thickness, we recommend a test run with your recipe.

Q: Why won't my gua bao open after steaming?
A: Usually there was too little oil at the fold or the dough sheet was too wet, so it stuck together during steaming. In machine production, keep the amount of oil consistent.