Kemach is meal; solas is fine flour. They are not the same. The Talmud Bava Metziah 87a wonders how we reconcile these contrasting “flours” in the same cakes. They explain that Avraham Avinu asked for fine flour. Sarah Imeinu responded with inferior flour. Chazal conclude from here, that we may derive that a woman is stingier than a man toward guests. Anyone who studies Torah understands that this dialogue between Avraham and Sarah contains more than meets the eye. Especially noteworthy is the fact that Hashem had earlier instructed Avraham to listen to Sarah, because she was greater than him with regard to nevuah, prophecy. Moreover, we find in Sefer Mishlei that Avraham praised Sarah for her open hand in doling out food to travelers. As I said, this is another perspective which demands an additional level of understanding of the dialogue. For this, we must plumb the depths of Torah exposition.
The Chasam Sofer illuminates the debate (Derashos chelek bais daf 403), explaining that Avraham Avinu’s hospitality towards wayfarers consisted of two components: physical nourishment; and spiritual sustenance. Indeed, Avraham would employ the physical provision to cultivate a conversation about G-d and spiritual growth. Thus, the Chasam Sofer explains that the debate between Avraham and Sarah concerning the quality of flour to serve the guests was not referring to physical flour, but rather, the spiritual definition (with regard to Torah study) of kemach, inferior flour, and solas, fine flour.
In the Talmud Nedarim 38a, Chazal state that the laws of the Torah were intended for all of Klal Yisrael, with pilpul, dialectic, to be reserved for Moshe Rabbeinu. Hashem taught Moshe a methodology by which to derive keen insights from the Torah’s text. Moshe, however, generously imparted this methodology to all of Klal Yisrael. [Maharasha explains that, while the entire law applies to the entire nation, the issue at hand was concerning the study of Torah’s text and the corollary capacity to rule on the Torah, which was to be the prerogative of Moshe alone, and his descendants.]
The Chasam Sofer continues: Hashem sought to impart the Torah to Klal Yisrael in a clear-cut, unambiguous state, leaving no room for any logical dialectical. Moshe, however, was hoping to increase the nation’s merits by giving each man the opportunity to delve deeper and deeper, plumbing the depths of Torah knowledge, exerting himself, diligently applying himself to its study and perfection of its knowledge. Is this better than error-free, absolutely – perfect Torah? There is also the fear that, through the application of one’s own logic, he might approach the halachic application with tainted logic. This was the “debate” between Hashem and Moshe, and, likewise, says the Chasam Sofer, it was the debate between Avraham and Sarah.
Our patriarch insisted on solas, fine flour, Torah in its pristine halachic form, leaving no room for dialectic, allowing for no false logic, no misguided analysis to creep in. (We have witnessed throughout history that those whose beliefs are misguided think along the same lines in order to validate their ignominious deeds.) Sarah insisted on kemach. Let the people learn, study, exert effort, toil in Torah, submerge in its depths until they bring up its pearls of wisdom. Moshe Rabbeinu bequeathed the power of pilpul, dialectic, to Klal Yisrael. Avraham lauded Sarah, piah paschah b’chochmah, “She opens her mouth with wisdom.” She disputed Avraham by insisting on kemach. This was a wise choice. Our Matriarch saw the value of Torah study amid toil. Their debate was how to make the best “bread”: Torah knowledge and observance.