Wheat is a grain that grows wild in Israel. The original strain of wheat which has been honed throughout human history comes from the Galilee. Wheat is divided into different products. The most popular is white flour. However, the highest quality is Semolina flour called Solet in Hebrew.
Semolina seems to be the first wheat product discussed in the Torah. Avraham Avinu served a massive amount of semolina cake to the angels who came to visit him while sick, after his circumcision. He asked his wife Sarah Imenu to prepare three Se’a of Semolina cake. This equals more than 15 kilo (33 lb) Some say that he actually made the 15 kilos of Semolina cake. He might have invited his entire household of workers, associates and students. Ramban says that Sarah might have filtered 15 kilos of wheat flour and ended up with 5 kilos of quality semolina.
Semolina flour is produced by sifting away the courser bran. The semolina flour is thicker than white flour, so when it is sifted the semolina stays in the sieve. Our Rabbis of Blessed memory have used semolina as an allegory. Ezra Hasofer made Aliyah with the Jews of Bavel before building the Second Temple. He only encouraged Jews of the lowest pedigree to move to Israel. He took the lowest class of Jews to Israel, They said that he did not go up to Israel until he made the higher class Babylonian Jews, who remained in Bavel, into pure semolina flour. (Ha’ruch, Kedushin 69)
The finest student is compared to semolina sieve. The leftover is passed through the sieve while the high quality, thicker semolina stays on top. (Avot 5-15)
There are many grain sacrifices in the Bet Hamikdash which use Semolina. When you serve G-d you must give the highest quality sacrifice even when it is just a meal offering.
The Jews of India have a wonderful custom. They prepare special cookies on the Shabat that we read Parashat Vayera. They are made of flour or semolina, sugar and water.