THE OMER WAS GROUND INTO FINE FLOUR

The Mishnah Menachot 10:1-5 describes the ceremony.

If the barley was ripe it was taken from the vicinity of Jerusalem; otherwise, it could be brought from anywhere in Israel. It was reaped by three men each with his own scythe and basket. The grain was then brought to the Temple where it was threshed, parched, spread on the courtyard floor to be dried by the wind, milled and ground into fine flour.