Special powder is good.

1. Good degree of fineness: Teyi flour is fine, has few impurities and is whitish. It is a high-grade flour. Specially refined flour is a flour with rough surface, many impurities and blackening, and is a low-grade flour.

2. High protein content: Teyi flour is also called strong gluten flour and has high protein and gluten content. Specially refined flour is low-gluten flour, also known as weak-gluten flour, with low protein and gluten content.