Arukh HaShulchan, Orach Chaim 313:5-13

Sugya Map

• Issue: The parameters of Mevashel (cooking) via Toldot HaChama (heat derived from the sun) on Shabbat.
• Nafka Mina: Whether chama is functionally equivalent to eish (fire) regarding bishul or simply a gezeirah (rabbinic decree) to prevent confusion with eish.
• Primary Sources: Shabbat 39a, Shulchan Aruch, Orach Chaim 318:3, Arukh HaShulchan, Orach Chaim 313:5-13.

Text Snapshot

• Arukh HaShulchan 313:9: "וכל זה הוא מדברי סופרים... דמדאורייתא אין בישול אלא באש."
• Nuance: R' Epstein emphasizes that bishul by sun-heat is midivrei sofrim (rabbinic). Note the dikduk on ein bishul ela b'eish—he grounds the exemption in the classic machloket regarding the melacha definition.

Readings

• Rambam (Hilchot Shabbat 9:3): Maintains that cooking with toldot ha-chama is forbidden rabbinically to prevent error with toldot ha-eish.
• Arukh HaShulchan (313:10): Chiddush: Even if the sun-heat is concentrated (e.g., via a lens), he argues it remains toldot ha-chama and is only rabbinically prohibited, resisting the Magen Avraham’s stricter classification of concentrated sun as eish.

Friction

• Kushya: If the heat is sufficient to sear meat, why distinguish between solar and fire heat?
• Terutz: The melacha requires the ma'aseh (act) of eish. Chazal focused on the source, not merely the thermal effect. Thus, toldot ha-chama lacks the "fire-like" melacha identity.

Intertext

• Shabbat 38b: The Gemara’s discussion of chama vs. toldot chama.
• Mishnah Berurah 318:32: Contrasts with the Arukh HaShulchan by suggesting that modern technological heat sources might carry stricter status than the Arukh HaShulchan’s lenient stance on solar derivatives.

Psak/Practice

• Follow the consensus: While toldot ha-chama is d'rabanan, the poskim treat it as a shvut that effectively mirrors the melacha of bishul. One does not rely on the d'rabanan status to circumvent cooking; rather, it informs she'eilot regarding solar water heaters.

Takeaway

The Arukh HaShulchan reminds us that melachot are not merely physics (heat transfer) but formal categories defined by their ma'aseh (fire-based agency); bishul requires fire, not just calories.