Flour Types (Bread, All-Purpose, Cake) and Machine Production

Flour is the backbone of the wrapper; choose the wrong flour, and even the best machine cannot make a good wrapper. Flour on the Taiwanese market is broadly divided by protein content and gluten strength into high-gluten (bread flour), medium-gluten (all-purpose flour), and low-gluten (cake flour), and some mills further subdivide into extra-high-gluten, patent flour (粉心粉), and others. Classifications and names are not entirely consistent between brands; the most reliable way to judge is the nutrition label on the package: the more grams of protein per 100 grams, the more gluten it can form and the tougher the dough.

How Gluten Strength Affects Machine Production

When flour is mixed with water, its proteins form a gluten network that gives dough elasticity and extensibility. For a machine, this network is the key to whether the wrapper can be stretched around the filling and whether it can seal after cutting.

• Gluten too strong: The dough has a strong tendency to shrink back; after being stretched, it wants to pull back, so wrapped shapes tend to drift, and cuts are harder to seal. Thickness springs back during sheeting.
• Gluten too weak: The wrapper does not have enough stretch, tears easily during encrusting, and turns mushy after boiling or steaming.
• Just right: Stretches without shrinking back, seals well, and has chew after cooking.

Which Flour for Dumpling Wrappers?

Dumpling wrappers need to hold up to boiling and have stretch, so all-purpose flour is generally used, and some factories blend all-purpose and bread flour to adjust the texture. A Da-Yeh University study that made dumpling wrappers from five types of flour found that the higher the crude protein content of the flour, the higher the tensile strength of the wrappers; but protein content was negatively correlated with weight gain and loss on cooking, meaning wrappers with enough gluten strength are less likely to turn mushy when boiled. For frozen dumplings, you also have to consider whether they crack after freezing; see Frozen Quality: What to Do When Wrappers Crack or Dry Out.

Which Flour for Steamed Buns and Mantou?

All-purpose flour is the most common for steamed buns and mantou, because its protein and gluten strength are moderate, giving a fine crumb after fermentation and buns that stand tall after steaming. Research comparing flours of different gluten strengths for mantou has found all-purpose flour to be the most suitable for making mantou; bread flour also performs well with medium-heat steaming, but when the heat is too high, mantou made with both all-purpose and bread flour may shrink and wrinkle after being taken off the heat. For chewier skins and taller buns, you can blend in a small proportion of bread flour; for a softer texture, some blend in some cake flour. For fermentation-related points, see What to Watch When Running Fermented Dough on a Machine.

What to Watch When Changing Flour

1. Retest the water amount when you change brands: Different flours absorb water differently, and the same amount of water can give very different firmness; see also How Dough Water Content Affects Machine Production.
2. Run a small batch first: Confirm that tearing, sealing, and weight are all stable before mass production.
3. Keep lot number records: When a product has problems, you can trace which flour lot was used.
4. Weigh blends accurately: When blending all-purpose and bread flour, if the proportion is slightly off, the gluten strength will drift.

Dong-Yih Machinery's automatic steamed bun and mantou machine, the DY-201, can make meat buns, vegetable buns, xiaolongbao, mantou, silver thread rolls, and more. To do a test run with your own flour and recipe, please call 06-257-4644.

FAQ

Q: Should dumpling wrappers use bread flour or all-purpose flour?
A: All-purpose flour is generally the main flour; for more chew or better boiling resistance, you can blend in some bread flour, with the proportion decided by actual testing.

Q: What flour is used for steamed bun dough?
A: All-purpose flour is the most common; its moderate gluten strength gives a fine crumb after fermentation and buns that stand tall after steaming.

Q: How can I tell whether a bag of flour is bread flour or cake flour?
A: Look at the protein content on the nutrition label; the more protein per 100 grams, the stronger the gluten usually is.

Q: What happens when gluten that is too strong runs on a machine?
A: The wrapper shrinks back, shapes tend to drift, seals do not close easily, and thickness springs back during sheeting.