The Torah commands ( 16:3) that during the Pesah holiday no hametz be eaten, rather that only matza – lehem oni – can be eaten. Lehem oni is usually translated as “the bread of affliction.” In the context of our Gemara it is understood to mean “poor bread.”
The Sages taught that the phrase poor man’s bread [lehem oni] excludes matza that was boiled [halut] in hot water after it was baked, which is considered to be a relative delicacy; and this expression also excludes matza that was baked as a large cake [ashisha]. I might have thought that a person fulfills his obligation to eat matza only with coarse [hadra’a] bread; therefore, the verse states: “Matzot,” “matzot,” which serves to amplify and include matza prepared with fine-grade flour. And in fact, one could fulfill his obligation even with matzot like those of King Solomon, which were prepared from the finest sifted flour. If so, what is the meaning when the verse states: “Poor man’s bread”? This phrase comes to exclude boiled matza and large cakes, but it does not exclude matza prepared from refined flour.
The Gemara on our daf brings this baraita that understands “lehem oni” to exclude halut and ashisha. These terms are unclear and are subject to a disagreement among the rishonim. Rav Hai Gaon explains that the dough was “boiled” in oil or honey and it is, therefore, considered matza ashira – “rich matza” – that cannot be used. Others understand that the dough was actually boiled (similar to the process used today to make bagels) and cannot be used either because boiling gives it a certain importance that negates the “poor bread” that we need (Ra’avad and others), or because the boiling process does not produce an end-product that is considered to be bread at all (Rabbenu Yehonatan).
An ashisha is a large cake. According to some rishonim, its very size gives it a certain importance that is problematic, as noted above. According to Rabbenu Yehonatan, the ashisha is kneaded together with oil or honey, again creating a situation of matza ashira.
The Gemara rejects the suggestion that lehem oni teaches that only pat hadra’a can be used – i.e. that low grade flour need be used – arguing that even King Solomon’s matzot, made of the finest flour, could be used as matza. While all commentaries agree that the pat hadra’a mentioned means something baked from low-quality flour, the actual definition of the term is subject to dispute. According to the Maharam Halavah quoting the Rambam, the word means “a worm” and the reference is to worm-eaten flour. The Aruk had a slight variation on the reading of the word; his version is harda’a, whose source is the Latin horedeum, meaning barley. According to this, the suggestion raised in the Gemara is that normal wheat flour should be rejected for the “poor bread” and replaced with a lower quality barley grain.