In brief
Tangzhong involves heating a portion of a recipe’s flour and liquid into a thick paste, then incorporating it into the remaining dough.
Useful to know
Tangzhong involves heating a portion of a recipe’s flour and liquid into a thick paste, then incorporating it into the remaining dough. King Arthur links the method to pre-gelatinizing starch and retaining more moisture in suitable soft breads. [1]
The paste is not extra flour and water added outside the formula: its ingredients come from the recipe’s totals. Tangzhong also differs from yudane, in which flour is scalded with boiling water. Do not automatically transfer the same ratio and procedure between the two methods.
Sources
For further detail and to check the information: