Filling Temperature: Why Fillings Are Often Chilled Before Going on the Machine

In bun and dumpling factories, you often see workers push freshly mixed filling into the walk-in cooler and take it out to run on the machine only after a while. This is not just habit; there are very practical reasons: temperature changes a filling's firmness and its release of water and oil, and it also bears on food hygiene.

Should Meat Filling Be Chilled First?

We recommend it. Chilling meat filling has several benefits:

• Firmer: At low temperatures, the fat in meat filling solidifies and the protein network stabilizes, so it holds together when extruded rather than spreading.
• Less water and oil release: As the temperature rises, fat softens and water seeps out, soaking the wrapper.
• Seals stick well: Only when the filling is not wet will the dough stick together when the shutter cuts and seals.
• Hygiene: Raw meat filling is an ingredient in which microorganisms grow easily, and the longer it sits at room temperature, the higher the risk.

Meat filling also warms up as it is mixed, so many factories add ice water or crushed ice during mixing to control temperature and chill it after mixing; see Meat Filling (Adding Water, Mixing, Stickiness).

Does Temperature Affect Weight?

Yes. Encrusting machines and dividing machines mostly feed filling by volume or a fixed stroke, and as temperature changes, so do the filling's firmness and flowability:

• When filling softens, it is more easily compressed or flows back in the passages, so the amount extruded drifts.
• Once the fat softens, the filling gets slippery and may slip during feeding.
• When a tub of filling is taken out of the cooler, the first part is cold while the last part has already warmed up, so weights differ from start to finish.

So to stabilize weight, run the filling within a fixed temperature range and top up in small amounts frequently from the cooler, rather than taking it all out at once. For troubleshooting weight problems, see Inconsistent Piece Weight.

High-Fat Fillings

High-fat fillings such as meat filling with a lot of lard, sweet fillings with butter, lotus seed paste, and sesame filling are especially sensitive to temperature. As they warm up, they soften and get slippery, tending to seep out of the seal and keep the dough from sticking; when too cold, they are too firm and hard to feed. The approach is to find the temperature at which that filling is easiest to work with, take it out of the cooler, let it warm slightly to that state before running it on the machine, and record it. For oil content in sweet fillings, see also Hardness and Oil Content of Sweet Fillings.

What the Hygiene Regulations Say

Articles 4 and 5 of the Regulations on Good Hygiene Practice for Food (食品良好衛生規範準則, GHP; most recently amended June 4, 2025) require food businesses to manage the hygiene of their premises, facilities, and equipment, as well as personnel and equipment and utensils, in accordance with Annexes 1 and 2. Article 8, Subparagraph 7 provides that during transport, the ambient temperature of vehicle compartments carrying refrigerated food must not be higher than 7°C, and for frozen food not higher than -12°C. The annexes to the regulations contain additional provisions on refrigerated and frozen storage, and after the 2025 amendment some provisions take effect in phases; for actual figures, refer to the current articles and annexes in the Laws & Regulations Database of the Republic of China (Taiwan). There is no uniform regulatory figure for how cold the filling should be before going on the machine during processing; it should be set according to product characteristics and your own hygiene management plan.

Dong-Yih Machinery's dividing machine DY-528M can divide all kinds of fillings. For the machine-ready condition suited to different fillings, please call 06-257-4644.

FAQ

Q: Should meat filling be chilled after mixing?
A: We recommend chilling it before going on the machine: it is firmer, does not release water or oil, seals well, and is more hygienic.

Q: Does filling temperature affect the weight of each piece?
A: Yes. Once filling softens, it is easily compressed or flows back in the passages, so the weight drifts. Run the filling within a fixed temperature range.

Q: How do I run a very oily filling on the machine?
A: Chill it first so the fat solidifies, then let it warm to the state that is easiest to work with before running it, and top up in small amounts frequently.

Q: Do the regulations specify refrigeration temperatures?
A: The Regulations on Good Hygiene Practice for Food do; for example, refrigerated compartments during transport must not be higher than 7°C. For storage figures, refer to the current annexes in the Laws & Regulations Database.