Commentaire sur La Genèse 18:6

קמח סלת MEAL, FINE FLOUR — The fine flour (סלת) for the cakes, the meal (קמח) for the dough used by cooks to place over the pot to absorb the scum (Bava Metzia 86b).

MEAL, FINE FLOUR. The fine flour for the cakes; the meal for the dough used by cooks to place over the pot to absorb the scum. Thus the words of Rashi. And so it is found in Bereshith Rabbah.⁸⁶48:13, with changes. Now there the Sages explained that there were three measures of meal and three measures of fine flour for each one of the guests. But we do not know why he served so much bread for three men. Perhaps he was aware of how the food disappeared successively,⁸⁷See above, Note 51. and it was as if he was offering more Burnt-offerings upon the altar, or perhaps because in their honor chiefs of his house dined with them.
By way of the simple meaning [of Scripture, the verse is to be interpreted as follows: Make ready quickly three measures of meal to make of them fine flour. Thus from the entire three measures of meal, they extracted a bit of fine flour.

CHOICE FLOUR. Wheat flour, for wherever it says "solet," it is from wheat, as is expounded from the consecration offering, where it is written (Ex. 29:2), "make these of choice wheat flour" [solet hitim].