On Shabbat, the sages prohibited heating any type of food, even if it is fully cooked. This means that even when heating is not considered “cooking” (for example, when the food is completely cooked and in a solid state), the sages still prohibited it out of fear that one might manipulate the fire to speed up the heating, or because it still appears as if one is cooking. However, this applies when one wants to heat the food over direct fire (for example, on a gas or electric stove), or over coals as was done in the past. But if one wants to heat the food on an electric hot plate, it is allowed, since it is not customary to cook on it, nor can the temperature be adjusted. Nevertheless, certain conditions must be met, which we will mention below.
What are the conditions for heating food on Shabbat? (For example, if you take it off the hot plate and want to put it back, or if it was in the refrigerator).
1. The food must be completely cooked.
2. The food you want to heat should be without sauce or juice, as heating a food in a liquid state is considered cooking according to Halacha.
3. The electric hot plate must not have a temperature regulator. (If it does, you must place an interruption between the food you want to heat on Shabbat and the hot plate itself. Consult a rabbi for precise guidance on how to proceed).
Can bread be placed on the electric hot plate to toast it?
Yes, it is allowed, as the bread is completely baked (if that is the case), and there is no issue with heating it. Even if you heat it a lot to make toast, it is allowed. (Some authorities prohibit this). If you take the bread out of the freezer and it has ice around it, you must remove the ice before placing it on the hot plate, as the ice will melt from the heat of the plate, which is considered cooking.
Can a cheese empanada be placed on the hot plate if the cheese will melt?
Yes, it is allowed, as the cheese is in a solid state when you place it to heat. The same applies to any food that is solid in its natural state and melts with heat. If it is previously cooked, it is permitted to heat it on Shabbat when it is in its solid state. (Ashkenazim are more stringent in this matter).
I have food on the hot plate and see that it is drying out. Is it allowed to add water?
No, because in that case, you would be cooking the water you add. Even if the water is boiling in a kettle also on the hot plate, it is still prohibited. The reason is that although the water is completely hot, when it leaves the container, it loses some heat, and upon entering the hot food pot, it is considered that this water is being cooked again. The same applies if you remove the pot from the hot plate; as long as it remains hot in the same container (keli rishon), it is prohibited. But if the food has been transferred to a tray (keli sheni), you are allowed to pour both cold and hot water into it. (In the case of adding hot water, it is correct that the hot water should not be poured directly from the kettle or thermos where it was heated (keli rishon) but should first be transferred to another container (keli sheni)).
If I want to warm a pot of food with juice or a container of water, can I place it on the electric hot plate, ensuring it does not reach the level of cooking?
No. We are afraid that you might get distracted and forget to remove it before it reaches the cooking point.
[1] See Chazon Obadia (Shabbat volume 4, page 344). And Menujat Ahab (volume 2, page 347).
[2] The first position is that of Rabbi Obadia Yosef (Jazon Obadia mentioned above, p. 290). But there are those who prohibit it for various reasons. Among them the ben ish chai (responses Rab Pealim volume 2. Responsa 52), the chacham Ben Zion Abba Shaul (Or Letzion volume 2, chapter 30 responsa 6), and Rabbi Moshe Levy in the book Menujat Ahaba (volume 2 page . 367).
[3] See Shulchan Aruch (253,4). Chazon obadia (shabbat volume 4, page 388). Or Letzion (volume 2. Cap. 17. Responsa 8). Biur Halacha (318, 4. Title: “dehave”).
[4] The temperature point considered “cooking” in liquids is what is called “iad soledet bo”. That is to say, the hand burns. And the Ben Ish jai (year 2, perashat Bo. Halacha 5) explains that it is the point at which consumption is impossible due to its temperature. There are those who said it is approximately 40 degrees. See Or Letzion (volume 2. Cap. 30. Responsa 12). Chazón Obadia (shabbat volume 4. Page 370).
