Mishneh Torah, Leavened and Unleavened Bread 1

Sugya Map

• Core Issue: The legal definition of "eating" (achilah) regarding chametz on Pesach, specifically concerning transformation into liquid form (memacheh) and the resulting liability for karet.
• Primary Sources: Pesachim 21b, Chullin 120a, Tosefta Pesachim 1:1, Mishneh Torah, Hilchot Chametz U’Matzah 1:1.
• Nafka Mina:
  • Whether shtiyah (drinking) is inherently achilah or requires a specific scriptural inclusion (ribui).
  • The transition of measurement from kazayit (solid) to revi’it (liquid).
  • The status of mixtures where the chametz loses its identity or consistency.

Text Snapshot

Mishneh Torah, Chametz U’Matzah 1:1:

"אחד האוכל ואחד הממחה ושותה" (One who eats and one who dissolves [it] and drinks [it])

Dikduk/Leshon Nuance: Rambam uses the term memacheh (dissolves/liquefies). The Maggid Mishneh notes the tension between this and the Talmudic derivation. By placing memacheh as an active verb (pa'el), Rambam implies that the human act of transformation is the mechanism that equates drinking to eating, rendering the liquid a legally significant "foodstuff."

Readings

1. Nachal Eitan

Chiddush: Nachal Eitan resolves the contradiction between the kazayit measurement for eating and the revi’it requirement for drinking. He argues that when the Torah or Sages refer to a kazayit for a liquefied substance, it refers to the volume of the solid before it was liquified. Once it becomes a liquid, the legal standard shifts to revi’it. The kazayit remains the baseline for the cheftza (the object), while revi’it is the standard for the gavra (the consumption act) once the substance enters a liquid state. This preserves the Rambam’s consistency across Hilchot Nazirut and Hilchot Shabbat.

2. Seder Mishnah

Chiddush: Seder Mishnah tackles the Lechem Mishneh’s critique regarding the source of shtiyah as achilah. He argues that the Rambam maintains a "natural" approach: eating and drinking are both acts of achilah based on the svara (rational logic) that people say "come, let us taste/eat/drink." He rejects the necessity of a ribui from the word nefesh in every instance, suggesting that the Talmudic ribui acts only as a clarification for specific, non-obvious cases. This elevates achilah to a functional definition (satisfying the body) rather than a rigid taxonomic one.

Friction

The Kushya: The Lechem Mishneh (to Hilchot Sha’ar Avot HaTumah 3:10) raises a devastating critique: Rambam consistently cites the verse "the soul" (nefesh) from Chullin 120a to include shtiyah as achilah. However, the Talmud in Chullin explicitly derives this from the word nefesh because the act is not inherently eating. If it were inherently eating, no ribui would be needed!

The Terutz:

1. The "Conceptualization" Defense: One could argue that the ribui serves to elevate a substance that would otherwise be considered "spoiled" or "non-food" into the category of achilah. Thus, the ribui doesn't define drinking as eating; it defines the liquefied substance as a foodstuff.
2. The "Svara" Defense: Following Seder Mishnah’s line, the ribui is a fallback. The fundamental legal reality is that drinking is eating, but the Torah provides the ribui to silence any claim that "drinking" is a distinct, non-punishable mode of consumption for forbidden substances. The kushya is essentially a dispute over whether the Torah's language is descriptive or constitutive.

Intertext

• Pesachim 21b (Chizkiyah vs. R. Abahu): The Rambam’s shifting reliance on Chizkiyah (for chametz benefit) vs. R. Abahu (in Ma'achalot Asurot) highlights the halachic tension between local derivation and general principles. The Kessef Mishneh notes that the Rambam prioritizes the most explicit derivation, even if it contradicts a general rule he applies elsewhere.
• Shvuot 22b: The discussion on nefesh and achilah regarding ma'aser sheni provides the necessary parallel. The debate there—whether the inclusion of drinking is a svara (logic) or a kra (scripture)—is the exact "DNA" of the Rambam's methodology in Hilchot Chametz U’Matzah.

Psak/Practice

In modern halachah, the kazayit vs. revi’it calculation is critical for chametz mixtures. Per Shulchan Aruch HaRav (486), we follow the more stringent Tosefot opinion for Torah-level kazayit measurements. When consuming liquid-based chametz (e.g., grain-based sweeteners or syrups), if it is "dissolved" (not merely a mixture), the revi’it standard is the functional threshold. If the chametz has not been fully liquified or is a solid suspended in liquid, the kazayit remains the operative threshold for karet. Always prioritize the kazayit of the solid component if it retains its cheftza status.

Takeaway

• Achilah is not restricted to mastication; it is defined by the body's consumption of a substance.
• Liquefaction is a legal "event" that forces a measurement shift from volume of the cheftza (solid) to the volumetric capacity of the consumption act (liquid).