Raw black sesame has high oil content and hard cortex, which is not conducive to digestion. The finer the food, the easier it is to digest and absorb, but sesame itself is small, so it is difficult for machinery to grind it into uniform fine powder.
Sesame is steamed and dried for nine times (Compendium of Materia Medica records that everything washed with water must be dried, steamed with wine and dried from beginning to end). That is, from 10 in the morning to 10 in the afternoon), stir-frying, and mashing into powder after the black cortex is completely broken, so that sesame seeds can be more easily absorbed and utilized by the human body.
Extended data:
Ge Hong said in his book "Bao Puzi" that eating such black sesame pills will "eat for a hundred days, except for chronic diseases, one year's skin will shine, two years will turn black, three years will lose teeth, four years will not be invaded by fire and water, and five years will live forever." Sun Simiao believes that "the eyes are bright and the intestines are soft as tendons."
Baidu encyclopedia-nine steaming and nine drying