Filling Viscosity, Particle Size, and Water Content

When an encrusting machine feeds filling, it pushes it forward, meters it, and then extrudes it into the wrapper. If the condition of the filling is unstable, no matter how precise the machine is, it cannot wrap accurately. The three problems most often encountered on the production floor are filling that is too runny, particles that are too large, and filling that releases water.

What Happens When Filling Is Too Runny

Runny filling flows too easily, leading to:

• Leaking and exposed filling: When the shutter cuts and seals, filling squeezes out through the parts that have not yet closed.
• Inaccurate metering: Runny filling flows back or drips in the feed passages, so the amount of filling in each piece varies.
• A soaked wrapper: Water seeps into the dough, making the wrapper soft and sticky and prone to tearing.

Filling for machine production should "hold together": when scooped up with a spoon, it mounds rather than spreading flat, and when extruded, it comes out as a strand, not a puddle. The test is simple: put a spoonful on a plate and let it sit for a few minutes. If water or oil seeps out around the edges, or the whole mound slowly spreads, it will most likely cause problems on the machine. Meat filling can be made cohesive by mixing until sticky, vegetable filling by dewatering and binders, and sweet filling by controlling the dryness and oil content during cooking; for specific methods, see the three articles on meat filling, vegetable filling, and sweet filling.

How Finely Should Vegetable Filling Be Chopped?

There is no universal number for particle size; it depends on the machine's feed structure and the product size. The principles are:

• Particles should be much smaller than the feed passages and nozzle, or they will get stuck, causing intermittent feeding.
• Particle size should be uniform: if sizes vary too much, large pieces make some pieces especially heavy and can easily puncture the wrapper.
• Be especially careful with hard or sharp items, such as uncut vegetable stems, cartilage, or shrimp shell, which can slice through the dough.
• The smaller the product, the finer the filling: the filling particles for xiaolongbao and small dumplings naturally need to be finer than for large steamed buns.

Some encrusting machines have options for handling solid ingredients; for example, the product page for RHEON USA's KN551 lists an optional solid-ingredient feeder for adding whole solid pieces of filling. If an ordinary machine does not have this type of device, the filling must be processed until it feeds smoothly. For how large the particles your model can accept, follow the recommendations of the original manufacturer or machine maker.

What to Do When Filling Releases Water

Water release is mostly caused by vegetables that were not dewatered thoroughly, meat filling with too much added water, or filling left at room temperature for too long. Ways to improve:

1. Dewater the vegetables first, then mix them evenly with the meat or binders.
2. Control how much water is beaten into meat filling, so the water is held by the proteins.
3. Add an appropriate amount of binder, such as starch or breadcrumbs, adjusted to the product recipe.
4. Chill before going on the machine: cold filling is less likely to seep water and is easier to form; see Filling Temperature.
5. Top up in small amounts frequently, rather than leaving a large tub of filling in the work area for too long.

Dong-Yih Machinery's dividing machine DY-528M can divide fillings such as mooncake filling, mung bean paste, red bean paste, and sun cake filling. To find out whether your filling can run on the machine, bring a sample and call 06-257-4644.

FAQ

Q: What happens when filling is too runny?
A: It tends to leak, the amount of filling is inaccurate, and the wrapper gets soaked, softens, and tears.

Q: How finely should vegetable filling be chopped for machine production?
A: Clearly smaller than the machine's feed passages and nozzle, and uniform in size; the exact upper limit varies by model, so ask the manufacturer.

Q: What should I do if the filling keeps releasing water?
A: Dewater the vegetables first, control the amount of water in the meat filling, add an appropriate binder, and chill before going on the machine.

Q: Can an encrusting machine wrap whole pieces of meat or egg yolk?
A: Some models can be fitted with a solid-ingredient feeder; for ordinary models it depends on the structure, so check with the manufacturer first.