Hilchos Shabbos Table Learning
A Weekly Guide to Shabbos Laws for Personal Study and Family Discussion
✨ This Week’s Topic ✨
🫖 Yad Soledes Bo – The Minimum Heat of Cooking in Halacha
📜 The Law
- Definition
Yad Soledes Bo is the minimum level of heat at which Halacha considers food capable of being cooked. Chazal define it descriptively as “hot enough to scald a baby’s stomach” (Shabbos 40a), leaving its precise measurement subject to dispute among the Poskim.
⚖️ Halachic Ramifications
🔥 Heating Food on Shabbos
Heat below Yad Soledes does not cook and is therefore permitted even for foods normally subject to bishul, provided the food will not reach Yad Soledes even if left there all of Shabbos.
✅ Examples: • Pouring warm (non‑Yad Soledes) water directly onto tea leaves
- Adding salt to a non‑Yad Soledes kli rishon
- Adding cold water to a mikveh whose water is below Yad Soledes
- Warming moist food near a blech if it will not reach Yad Soledes
🍲 Reheating Liquids
- If a cooked liquid remains Yad Soledes, all agree there is no bishul achar bishul.
• If it cooled below Yad Soledes: – Ashkenazim are generally lenient
– Sephardim prohibit reheating
🥛 Kashrus – Ta’arovos
Taste transfer of non‑kosher food occurs only if the food is Yad Soledes.
✅ Example: Hot milk spilled on a meat utensil does not render it non‑kosher if the milk was below Yad Soledes.
🌡️ How Is Yad Soledes Determined?
🖐️ By Physical Sensation (Primary on Shabbos)
Since measuring temperature on Shabbos is forbidden:
- Finger test – If one cannot comfortably keep a finger in the heat for an extended time, it is Yad Soledes.
• Mouth test – If most people would avoid putting it directly into their mouth without blowing or shifting it around, it is Yad Soledes.
📏 By Temperature (Reference Only)
Poskim offer a wide range of estimates: • 40°C (104°F) – lowest opinions
• 43–45°C (109–113°F) – many Poskim; common Ashkenazi practice
• 50–71°C (122–159°F) – stringent opinions
• Sephardic stringency for reheating liquids: 71°C (159°F)
🧭 Bottom Line
Yad Soledes Bo marks the threshold of halachic cooking and affects Shabbos, reheating, and kashrus laws. • Below Yad Soledes → no cooking
• At or above Yad Soledes → treat as cooked
On Shabbos, rely on comfort‑based tests, not thermometers, and apply additional stringency according to minhag—especially for reheating liquids among Sephardim.
Sources:
Shabbos 40a; Shulchan Aruch HaRav; Igros Moshe;
Minchas Shlomo