Generally, flour has no small black spots, which may be unqualified flour. Small black spot impurities generally come from impurities such as grass seeds and carbon residue contained in raw grain that have not been completely removed.
The variety and quality of wheat itself will lead to the difference of starch content (the ratio of amylose to amylopectin) and starch particle size; The advanced processing technology and equipment of flour mill will affect the ash ratio (from wheat germ/bran), amylase activity (also related to ash), particle size (related to water absorption, viscosity, elasticity and ductility) and so on. Many small flour mills directly add gluten (active gluten powder) to flour to increase the protein content of flour. Gluten is enough, but due to the above factors, the dough you made is still sticky, inelastic and difficult to operate. At present, the average level of wheat planting, the average level of flour processing and the requirements for flour grade in China are not far from those in big countries, which is why many people who love to make bread are more willing to buy imported flour.