📋 Shiur Overview
Rambam Hilchos Shabbos Chapter 4 – Hatmanah
Introduction – The Topic of Hatmanah in the Context of Chapters 3-4
Chapter 3 dealt with shehiyah and chazarah — placing on the fire before Shabbos or returning to the fire on Shabbos. Chapter 4 deals with hatmanah — insulating the food in materials that retain heat, without fire. This is a different method of keeping food warm for Shabbos.
From both chapters (3 and 4) we see that Chazal held that it is an important thing to have hot food on Shabbos. The Rambam doesn’t say it explicitly, but the Rema in Shulchan Aruch says it clearly. This explains why they worked out so many halachos regarding how one may keep food warm — it’s not just anything, it’s a valuable thing. Another approach: perhaps from chapter 3 itself we already see that it’s permitted, and the prohibitions are only because of shema yachteh — this itself already emphasizes that it’s a valuable thing.
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Halacha 1: Davar Hamosif Hevel and Davar She’eino Mosif Hevel
Words of the Rambam: “There are materials that if one insulates food in them, they heat up and add to its cooking, such as gefes (olive waste), manure, salt, lime, sand, wet zagin (grape skins), wet mochin (cloth scraps), and herbs when they are moist — and these materials are called davar hamosif. And there are materials that preserve the heat but do not add — such as dry zagin, dry mochin, and dry herbs, clothing, fruits, pigeon wings, flax fibers, wood shavings, wool shearings — and these are called davar she’eino mosif.”
Explanation: The Rambam divides into two categories of materials for hatmanah: (1) davar hamosif hevel — things that make the food even hotter, (2) davar she’eino mosif — things that only maintain the warmth but don’t make it hotter. Three things (zagin, mochin, herbs) can be in both categories — when they are wet they are mosif, when dry they are eino mosif.
Novel Points and Explanations:
1. Novel point: “Davar hamosif” doesn’t mean it literally gets hotter. From a physical standpoint it’s impossible for a material that isn’t itself a heat source to make something else hotter than it already is. Even the best thermos (insulation) can only retain heat, not add heat. Therefore we must understand that “mosif hevel” means that it keeps the food almost at the same level of heat — it’s such good insulation that it can keep the food boiling hot, almost as it was. “Eino mosif” means that it keeps it warm but not at the same level. There are people who argue that one can actually find biological materials (like wet grass) that produce heat through fermentation/composting, but it’s expressed as doubtful whether this is what Chazal mean in the hatmanah context.
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Halacha 1 (continued): The Law of Hatmanah in Davar Hamosif — A Rabbinic Decree
Words of the Rambam: “According to the law it would have been proper to permit insulating in davar hamosif from before Shabbos… but the Sages forbade insulating in davar hamosif hevel even while it is still day, a decree lest the food boil on Shabbos and he will need to uncover it so that its boiling will subside, and he will return and cover it on Shabbos — and he will be found insulating in davar hamosif on Shabbos, and this is forbidden.”
Explanation: According to the law, hatmanah in davar hamosif before Shabbos would have been permitted, because it’s not cooking and not fire. But the Sages forbade it due to a decree: the food can become too hot, the person will need to uncover it on Shabbos to stop its boiling, and when he covers it back on Shabbos he is insulating in davar hamosif on Shabbos.
Novel Points and Explanations:
1. Why is hatmanah on Shabbos itself forbidden? The Rambam says that the ultimate problem is “and he will be found insulating in davar hamosif on Shabbos, and this is forbidden.” But why is hatmanah in davar hamosif on Shabbos itself forbidden? The Rambam in Perush HaMishnayos (chapter 3) brings that the decree is shema yitmin b’remetz — that it can lead to him insulating in hot coals. Other opinions: that hatmanah in davar hamosif on Shabbos itself looks too similar to cooking, or that he will come to place the food on the fire instead of in davar hamosif, and on fire one may not place even something fully cooked.
2. Question: He wants it not to be so hot — why would he place it on the fire? If the person uncovered it because it’s too hot (to stop its boiling), why would he go place it on the fire? The answer: “to stop its boiling” doesn’t mean it’s too hot in general — perhaps it means it’s boiling over, he only wants it to stop bubbling, but he still wants to keep it warm. These are two different things — he doesn’t want it to cook/bubble, but he wants it to remain hot. Therefore he can come to place it on the fire or back in davar hamosif.
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Halacha 1 (continued): Hatmanah During Bein Hashmashos in Davar Hamosif
Words of the Rambam: “Therefore it is permitted to insulate in davar hamosif during bein hashmashos, since they already boiled and subsided while it was still day — since they subsided, their remaining boiling hot, he is no longer concerned that he will need to uncover.”
Explanation: During bein hashmashos one may indeed insulate in davar hamosif hevel, because the food already cooked and settled (nachu) earlier, and it won’t become so hot that he would need to uncover it.
Novel Points and Explanations:
1. Bein hashmashos is more lenient than before Shabbos: An interesting point: bein hashmashos is more lenient than while it is still day! While it is still day one may not insulate in davar hamosif, but during bein hashmashos one may. The reason is because during bein hashmashos the food has already subsided (nachu), and there’s no longer the concern. Additionally, during bein hashmashos one may generally do rabbinic prohibitions, and hatmanah is only a rabbinic prohibition, and the decree of shema yachzor v’yitmin b’Shabbos is also only rabbinic.
2. Proof that “davar hamosif” doesn’t mean literally hotter: The Rambam says that during bein hashmashos it’s permitted because “they already boiled and subsided” — the food has already settled. If davar hamosif would literally make it hotter, this wouldn’t help — it could still become hotter! This proves that “mosif hevel” means that it keeps the food very hot (almost at the same level), but it can’t make an already-cooled food hot again. When the food has already subsided (nachu), the davar hamosif no longer has the power to bring it back to the boiling level.
3. Discussion: Perhaps davar hamosif is only when the food is very hot? Perhaps the distinction is as follows: when one places a very hot food into the materials, they have the power to keep it at that hot level (mosif/strongly retaining heat). But when the food has already subsided (nachu), the same materials no longer have the power to bring it back — therefore they already function like “eino mosif.” This is a novel understanding of the definition of “mosif” — it’s not a category of the material itself, but rather of the interaction between the material and the state of the food.
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Halacha 2: Hatmanah in Davar She’eino Mosif – On Shabbos Itself
Words of the Rambam: “According to the law it would have been proper to permit insulating food in davar she’eino mosif on Shabbos itself, except that even this the Sages forbade to insulate on Shabbos, a decree lest he insulate in remetz.”
Explanation: According to Torah law one should be able to insulate on Shabbos itself in davar she’eino mosif hevel, because it’s not cooking and there’s no concern. But the Sages forbade it even on Shabbos.
Novel Points and Explanations:
1. The reason for the decree – shema yitmin b’remetz: Remetz is a mixture of coals with fire, which contains sparks of fire. The concern is that if we permit insulating on Shabbos even in davar she’eino mosif, he will come to insulate in remetz, and then he is stirring the coals (choteh b’gachalim), which is close to kindling. This is a second level of decree — every hatmanah on Shabbos, even eino mosif, is forbidden because it can lead to hatmanah in remetz.
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Halacha 2 (continued): Doubtful Nightfall
Words of the Rambam: “Doubtful nightfall, doubtful if it has not become night — it is permitted to insulate the hot item.”
Explanation: When there is doubt whether it’s already night, one may still insulate a hot item.
Novel Points and Explanations:
1. Distinction between doubtful nightfall and bein hashmashos: Doubtful nightfall is not the same as bein hashmashos. Bein hashmashos is when the person knows for certain that it is bein hashmashos (which we already learned earlier that “ordinary pots during bein hashmashos are boiling”). But doubtful nightfall means that the person doesn’t know — it might be that it’s already completely night. Even then it’s permitted, because the prohibition of hatmanah on Shabbos is a weaker prohibition (rabbinic), and in cases of doubt it’s permitted.
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Halacha 2 (continued): Insulating a Cold Item on Shabbos
Words of the Rambam: “It is permitted to insulate a cold item on Shabbos in davar she’eino mosif, so that it should not become more cold, or so that its coldness should diminish.”
Explanation: A cold item may be insulated on Shabbos in davar she’eino mosif.
Novel Points and Explanations:
1. Two reasons – so it shouldn’t become more cold, or so its coldness should diminish: “So it shouldn’t become more cold” means that it shouldn’t become even colder. “So its coldness should diminish” means even that it should warm up a bit. Both are permitted with a cold item. We’re talking here about truly cold — “not hot at all” — not hot and not a bit hot, but truly cold.
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Halacha 2 (continued): Hot Water That Was Uncovered, Changing the Covering, and Transferring to a Second Vessel
Words of the Rambam: “Hot water that one insulated before Shabbos and was uncovered on Shabbos – it is permitted to cover it.” “It is permitted to cover the covering on Shabbos” — one may change the covering. “He removes coverings and places a covering” — one may change from one item to another. “Transferring the food from a vessel to another vessel” — if one pours from the first vessel into a second vessel, one may insulate that second vessel on Shabbos.
Novel Points and Explanations:
1. Hot water that was uncovered – fixing is not new hatmanah: When the hatmanah opened on Shabbos, one may cover it back. The reasoning is that he’s not adding any new hatmanah, he’s only fixing the same hatmanah that he already had from before Shabbos.
2. Changing the covering – even from mosif to eino mosif: One may change the covering from one davar hamosif hevel to another davar she’eino mosif hevel, or vice versa. But this only refers to covering (covering over), not to vessel upon vessel.
3. Transferring to a second vessel – the prohibition falls away: If one pours the food from the first vessel (the pot that was on the fire) into a second vessel, one may already insulate that second vessel on Shabbos. On this there is no prohibition.
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Halacha 3: Placing One Pot Upon Another Pot
Words of the Rambam: “One places a kettle upon a kettle on Shabbos, a pot upon a pot, a pot upon a kettle, a kettle upon a pot. And in their openings with stoppers. Not in order that they should be heated, but in order that their heat should remain.”
Explanation: One may place a pot on a warm pot on Shabbos, not so that it should become hotter, but so that it should remain warm. A kettle (meicham) is for water, a pot (kedeirah) is for cooked foods.
Novel Points and Explanations:
1. The principle – “upon” is not hatmanah: Hatmanah means when the pot is completely surrounded from all sides. But merely placing a vessel upon a vessel (al gabei) is not called hatmanah, therefore it’s permitted. Even if the lower vessel is davar hamosif hevel — because it’s not hatmanah, the prohibition falls away.
2. “Stoppers in their openings”: One may even plug the upper vessel at the opening (mouth) with a stopper. This is also permitted because it still doesn’t constitute hatmanah in the technical sense.
3. “Not that they should be heated but that their heat should remain”: The condition is that the purpose should only be to maintain the heat, not to make it hotter. This is the distinction why it’s permitted.
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Halacha 3 (continued): A Cold Vessel Upon a Hot Vessel
Words of the Rambam: “But one may not place a vessel that has something cold in it upon a hot vessel on Shabbos, for he is creating heat in it on Shabbos. And if he placed it before Shabbos – it is permitted.”
Explanation: A pot with cold items may not be placed on a hot pot on Shabbos, because one is creating heat (molid chom). But if one placed it there before Shabbos, it’s permitted.
Novel Points and Explanations:
1. “Molid chom” – what is the prohibition? What does the Rambam mean by “for he is creating heat in it”? Is this a prohibition of “molid” (a special category), or does he mean that it can become truly hot and then there’s a concern of cooking, or is it appearing like cooking (mechzei k’mevashel)? The Rambam doesn’t say explicitly what the problem is — he only says “creating heat in it” without further explanation.
2. Opinion of the commentators: The commentators say that it can become truly hot (namely, yad soledes bo), and then there will be actual cooking. Usually it doesn’t become truly hot, but it can happen.
3. Before Shabbos – permitted, because “upon” is not hatmanah: If one placed it there before Shabbos, it’s permitted. The reason: even if the lower hot vessel is davar hamosif hevel, “upon” is not hatmanah (because the vessel is not surrounded from all sides). And hatmanah in davar hamosif hevel before Shabbos is forbidden — but that’s only when it’s called hatmanah. Here, because it only sits on top of the pot, it’s permitted even from before Shabbos.
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[Digression: Crock-Pot]
There are people who hold that a crock-pot (slow cooker) is hatmanah in davar hamosif hevel, because the food is surrounded from all sides with heat. This is a practical application of these laws of hatmanah.
📝 Full Transcript
Rambam Laws of Shabbat Chapter 4 – Hatmanah (Insulation)
With God’s help, Rambam Laws of Shabbat Chapter 4.
We are holding in the middle of Laws of Shabbat, we are now going to learn the fourth chapter, hatmanah. In the previous chapter we learned about placing things on the fire on erev Shabbat, or returning them on Shabbat. Now we are going to learn when there is no fire involved, but rather one covers the food in merchandise or things that keep warm, the laws of what is permitted and what is forbidden.
And we must mention the sponsor of our shiur, the supporter of Torah, our friend the Rabbi R’ Yoel Halevi, who supports us so that we can produce the flour for the Torah. From him they will learn and so they will do.
Law 1: Davar HaMosif Hevel and Davar She’eino Mosif Hevel
The Rambam’s Words: Two Categories of Materials
The Rambam says, “There are things”, there are certain types of things… so the Rambam is going to tell us here what one may store in, it’s called hatmanah, storing the food. That is, on erev Shabbat there is another method. The previous method was that it should be on the fire on Shabbat. The other method is that you cook on erev Shabbat, and on Shabbat one should only store it in something that holds the warmth.
We see here in both chapters that there is a concept of having hot food on Shabbat. The Rambam didn’t say it clearly, but in the Shulchan Aruch… I mean the Rema says that there is a concept, the Rema goes like this, that there is a concept to eat a warm, hot food on Shabbat. We try, it’s not a lawless world, we don’t do many things we don’t do because of lest he stoke, but we calculate all the laws because it’s an important thing, it’s not just anything.
Yes, it could be that the Rambam meant that we saw the previous chapter, and we’re in the middle of saying that it’s permitted, there are only prohibitions because of lest he stoke, perhaps that’s what he’s emphasizing. I hear.
The Rambam says, “There are things”, there are certain types of things, “that if one insulates food in them”, if one places in them a warm dish, “they heat up and add to its cooking”, these things make the food become even warmer, and it helps to cook it, it adds cooking. Anyway, these things have heat almost like fire. Such as geft, waste from olives, manure, salt, sid. Sid is not paint, whatever, some kind of sand from which one usually makes lime. Etc., or sand, or zagin, I think it’s the shells, zagin chartzanim vezag, yes, it’s the shells from grapes, or mochtin is usually cotton, small pieces, and herbs, or grass, when they are moist from themselves, on these three things, zagin, mochtin, and herbs, if they are wet. All these things have a nature that they make things that are stored in them hotter.
And how are they called in the Gemara? The Rambam says, “And these things are called”, they are called in the… when one learns these things they are called “davar hamosif”, a thing that adds, that makes more heat.
But now he says, there are types of things that if one stores a dish in them “it holds the heat”, there are things that have the quality that they can keep warm, but they cannot make warmer. “And they don’t add to its cooking”, it doesn’t make it hotter, it only makes the food stay hot. That is, “they prevent it from cooling”, it only protects from becoming colder, it holds it. Such as zagin and mochtin and herbs, the three things that he enumerated, but “dry”, that are already dry. Or the other things are garments, merchandise, fruits, bird wings – feathers from a bird, ne’oret hapishtan – small pieces of waste, small pieces from flax, or sawdust from carpenters – small pieces of wood, and shelulin and gizei tzemer – two types of hide or skin from an animal.
All these things are also things that are good to store a dish in, but only to keep hot. This is called in the language of the Sages “davar she’eino mosif”, a thing that doesn’t add heat. The Gemara calls it “mosif hevel” or “eino mosif hevel”. The Rambam only says “mosif”.
Novel Point: “Davar HaMosif” Doesn’t Mean Literally That It Gets Hotter
Yes, I think one must understand, because I’ve seen people talk about this, I don’t remember what their final conclusion in it is, but simply it’s not possible that a thing that is not itself hot should make another thing hotter. That’s not the way reality works. Take the best thermos, the best insulation, put in it a hot soup, it stays very hot, but it doesn’t become hotter.
Apparently one must learn that when the Sages say davar hamosif, they mean like we have a good thermos, it holds it as if, let’s say, very hot, or it doesn’t become hotter than before. Or perhaps one mosif means that it keeps it not cold, not that it keeps it as hot as it was, or something like that, almost as hot. Because it’s very hard to believe that davar hamosif is literally that it becomes hotter.
I hear that there are those who will argue, and it makes some… there is some way that one can find some grass that should make hot, but it’s hard to believe that this is what we’re talking about in hatmanah.
Law 1 (Continued): The Law of Hatmanah in Davar HaMosif – A Rabbinic Decree
The Rambam’s Words: A Decree Lest He Boil and Return and Cover on Shabbat
Now, first of all the Rambam says a fact, right? Like a Mishnah. The Rambam says like this, apparently, just like that, from what we’ve learned until now, apparently there wouldn’t have been any problem in both of them, because there is no prohibition of cooking, and there is no fire. The Rambam says like this, according to the law it should have been, and it was, so originally the law was like this, that one may insulate even in davar hamosif hevel. If one wants to place a hot pot on erev Shabbat so that it should stay hot, one should be permitted to insulate from erev Shabbat even in a davar hamosif, even in the thing that adds or holds very strongly the heat, mosif hevel. “And the dish that is insulated should remain on Shabbat, and the dish should remain there on Shabbat, like on the fire on Shabbat”, I see here even a way that one may return to the fire, “a davar hamosif cannot be worse”.
But in practice, the Sages forbade insulating in davar hamosif hevel, the Sages did forbid insulating in the davar hamosif, even if one places it on erev Shabbat. Why? The decree is like this, we are afraid, because the thing is mosif hevel, “lest the dish boil on Shabbat”, the pot becomes very hot, and he’s afraid that it shouldn’t be too hot, he will temporarily remove the cover, he needs to uncover it a bit, in order to calm its boiling, so that it should ease a bit from the heat, and only afterwards and he will return and cover on Shabbat he will go cover it on Shabbat.
What is the problem then? When we say like this it comes out that he is insulating in davar hamosif on Shabbat, when he puts it back, he is again covering, he is then insulating in davar hamosif on Shabbat, and this is forbidden. Why exactly is this forbidden we also don’t yet know.
Discussion: Why Is Hatmanah in Davar HaMosif on Shabbat Itself Forbidden?
The Rambam in Perush HaMishnayot that stands in siman 3 says that the decree lest he insulate, must have the same decree lest he insulate in hot ashes. He brings that in Perush HaMishnayot it says something else, that if in the middle of Shabbat it can be too similar to cooking, or it looks itself like cooking, or as others say, so it says in the Shlomo and other places, or he says that the Rambam says that he came to heat on Shabbat, he will place it on the fire, on the fire one may not place on Shabbat, even though even a thing that is fully cooked, it looks too similar to cooking, and if he goes to open on Shabbat and put back, he came to place on the pot also something, on the fire also something, it will warm up more, so he brings, it’s also a bit unclear.
Question: He Wants It Not To Be So Hot – Why Will He Place It on the Fire?
Why then, he wants it not to be so hot, he opened it in order to calm its boiling.
Yes, but perhaps the calming from boiling is not the same as it being cold, perhaps this is something else. Do you understand like this? One cannot say the same detail, perhaps it’s cooking, perhaps it’s bubbling, he doesn’t want it to bubble, perhaps it’s bubbling over, so he warms himself afterwards. He needs to make sure it’s the right temperature. It can be two different things.
The point is hatmanah on Shabbat we certainly don’t know, therefore a davar hamosif, since it can cause that one should need to insulate on Shabbat, is also forbidden.
Law 1 (Continued): Hatmanah During Bein Hashemashot in Davar HaMosif
The Rambam’s Words: Permission During Bein Hashemashot
Therefore, it is permitted to insulate in davar hamosif during bein hashemashot. During bein hashemashot one may insulate in davar hamosif hevel. It’s not while it’s still day, but when it’s already becoming Shabbat.
Right.
And during bein hashemashot one may do hatmanah in davar hamosif hevel. Why is the reason? Because during bein hashemashot they have already boiled and calmed from while it was still day, they have already eased from the heat, therefore there is no longer the concern of he will need to uncover, since they have calmed from being boiling, therefore it won’t become so strongly hot anymore, there is no longer the concern of lest he need to uncover, the whole thing.
Discussion: Bein Hashemashot Is Easier Than Erev Shabbat
Speaker 1: Which is an interesting thing, because bein hashemashot, it seems bein hashemashot is a time when one may still do melachot.
Speaker 2: Rabbinic melachot.
Speaker 1: With rabbinic. It’s only a rabbinic prohibition hatmanah.
Speaker 2: But the whole question is lest he boil and return on Shabbat.
Speaker 1: Mm.
Speaker 2: It’s also only a rabbinic prohibition.
Speaker 1: Mm.
Speaker 2: Hatmanah is not a prohibition, it’s not cooking, cooking.
Speaker 1: No, but it’s interesting that bein hashemashot is even easier than on erev Shabbat, yes, because there isn’t the decree, yes.
Right. And here it also seems clear that he doesn’t say even a boiling pot is permitted. Permitted we learn because it’s already just a boiling pot, it’s interesting, they have already boiled.
We’re talking about, well, necessarily, if someone has a pot that is coming down from the stove, perhaps he may not, but during bein hashemashot he may, because a person doesn’t cook before Shabbat right during bein hashemashot, he cooks an hour earlier, and now he only wants to insulate so that it should be warm for the meal.
Proof That “Davar HaMosif” Doesn’t Mean Literally Hotter
And here you also see clearly that davar hamosif doesn’t mean that it becomes literally hotter, but that it can become boiling.
Speaker 2: But if that were the word, he would have said because then it’s not called mosif hevel. If like you say, because then itself it’s already not mosif hevel.
Speaker 1: It’s already not a davar hamosif. He doesn’t say like this, he says because it’s just because, they have already boiled and calmed.
Speaker 2: But one should have said that all these things that were said mosif is only when one places in a pot when it’s very hot it is mosif. When one places in a pot when it’s not very hot it’s not mosif hevel, it can no longer, it no longer has the power.
Speaker 1: I didn’t understand what we’re talking about. I’m just saying that I argued that davar hamosif doesn’t mean that it becomes literally hotter. If it were literally hotter, “since they have calmed from being boiling” wouldn’t be correct, because it can still become davar hamosif. Does this make hotter? The answer is no, it makes it stay very hot, but it doesn’t make hotter.
I didn’t understand what you answered, I still didn’t understand what you meant. I understand like this, that the davar hamosif is good enough that when you place a very hot pot, that it doesn’t keep strongly hot, but when you place not a hot pot,
Law 2: Hatmanah in Davar She’eino Mosif – On Shabbat Itself
I hold that there is a distinction. I don’t agree. I hold that there is a distinction. But then this is permitted. I mean, on erev Shabbat one may even lechatchilah.
The Rambam says further, “And likewise, according to the law it should have been permitted to insulate a dish in davar she’eino mosif on Shabbat itself”. According to the law one should have been permitted, there is no reason why one shouldn’t be allowed to insulate on Shabbat. It’s not cooking and it’s nothing. We’re talking about a davar she’eino mosif, there isn’t even a concern, it doesn’t look like cooking or what.
“But even this thing the Sages forbade to insulate on Shabbat”. Why? “A decree lest he insulate in hot ashes”. There is another way of insulating in hot ashes. Hot ashes means just a mixture of coals with fire, and there are sparks of fire in it. Then, if he insulates in hot ashes on Shabbat, this is raking the coals, this is close to being kindling. So, every thing that is, every insulating we are afraid lest he insulate in hot ashes. Even davar she’eino mosif, even on Shabbat, even she’eino mosif one may not. Why? Because he will then insulate in hot ashes, and then he is actually raking the coals.
Okay.
Doubtful Darkness
Not clear. And also, another thing, sorry, until here. The Rambam says, doubtful darkness or not darkness, when it’s a doubt if it’s already Shabbat. What may one do then and what not? It’s like this, it is permitted to insulate the hot thing. Then one may. Then there is not yet the prohibition of lest he boil, then there is still, one may still insulate in a hot thing.
We already learned this actually, that during bein hashemashot, because it’s not just pots during bein hashemashot that are boiling, this is not that. This is when during bein hashemashot, now he’s talking about a doubt. A doubt that it’s already actually night. Bein hashemashot is when he knows for sure that it’s bein hashemashot. A person doesn’t know, it could be that it’s already actually night. Then it is permitted. There is already a… in doubts it’s permitted, the prohibition of… this is a weaker prohibition.
Okay.
Insulating a Cold Thing on Shabbat
What may one do on Shabbat? On Shabbat itself, a thing that is not hot at all, it is permitted to insulate the cold thing on Shabbat in davar she’eino mosif. Why does he want to insulate it? So that it shouldn’t become too cold, or so that its coldness shouldn’t dissipate, so that it shouldn’t be so cold, or so that it shouldn’t become colder. One may. A cold thing, that its coldness shouldn’t dissipate means even to warm up a bit. A cold thing one may insulate on Shabbat. He doesn’t say hot and a bit hot, actually cold, like whatever, not hot at all. Permitted.
Hot Water That Was Uncovered, Changing Covering, and Transferring to a Second Vessel
Another thing, sorry, hot water that one insulated on erev Shabbat and was uncovered on Shabbat, it opened, the insulation didn’t hold, it is permitted to cover them. One may fix the insulation. It’s not she’eino mosif. He doesn’t add any new insulation, he goes the same insulation that he had, he fixes it. This is not a problem.
Right. And it is permitted to cover, what happens to the covering, the thing that one places on the pot? It is permitted to cover the covering on Shabbat. One may on Shabbat change the thing over the pot. How? He takes off the coverings, he may remove what was covered with coverings, and lift the pot there is still another covering. May one remove that and place a vessel on top of a vessel and put other merchandise? A vessel on top of a vessel is the thing that we talked about earlier, one of the things has a… one mosif hevel.
Yes.
Yes. So one may change. But not a vessel on top of a vessel, but rather place a covering. May change from one davar hamosif, one mosif, from the other davar she’eino mosif. What… what is already one mosif. What is not mosif. Already.
Transferring the dish and in it hot water from a vessel to another vessel. Until now we’re talking that he takes the pot that was on the fire and he wants to now insulate it. But if one takes a fresh pot and pours in the dish from the first vessel, from the pot that was on the fire, the second vessel one may already insulate on Shabbat. One may, on this there is not the prohibition.
Law 3: Placing a Kettle on Top of a Kettle
Next law. The Rambam says like this, what happens regarding not placing things directly on fire, but like this: One may place a kettle on top of a kettle on Shabbat. One may place a pot on a warm pot on Shabbat. Or kettle usually means a teapot for water. A pot is a pot for dishes, for solid things. One may place a kettle on top of a kettle, a pot on top of a pot, or a pot on top of a kettle, a kettle on top of a pot. And in their mouths are stoppers, one may even… stop up the upper kettle… the upper kettle or one means to say that both we’re talking with a stopper. What exactly? One may even place with the spout stopped. Not so that they should be heated, not that the upper pot should now become hot, but so that their heat should remain, but so that the heat should be maintained.
Why? Ah, you’re saying also that it’s like a davar hamosif hevel, the lower pot makes hotter the upper pot. But they only forbade insulating on Shabbat. The prohibition that the Sages said in hatmanah is only when one insulates, when one takes completely around a pot. But to place a hot vessel on top of a hot vessel so that its heat should remain, is permitted, so that it should stay warm is permitted. The distinction is whether he places it in, it’s surrounded by… hatmanah means when the pot is completely surrounded from all four sides, or the word is because it’s lying on something. In short, when it’s not called hatmanah one may.
A Cold Vessel on Top of a Hot Vessel
But one may not place a vessel containing something cold on top of a hot vessel on Shabbos. This is not permitted. That is, one may not place a pot that contains cold things that are completely cold on top of a hot pot on Shabbos, for he thereby generates heat in it on Shabbos. Through this he causes the upper pot to become warm.
What is the prohibition? Is the prohibition molid (generating something new), or is it mechazi k’mevashel (appearing like cooking), or is it a concern of mevashel (cooking)? For he generates heat in it. Does he mean that it’s a prohibition of being molid, or does he mean that it becomes hot? And we are stringent that it’s a concern of mevashel.
What? So it says here, I don’t know. So it says here, no?
Yes, but he doesn’t say, he says molid chom (generating heat), he doesn’t say what that means, what the problem is with this molid chom.
And one may place on erev… The commentators say that it can become actually hot, usually it doesn’t become actually hot, but it can become actually hot, and then there will be actual cooking. There are others who say differently, it’s not clear.
But if he placed it on erev, if one placed a vessel containing something cold on top of a hot vessel on Shabbos, on erev, before erev Shabbos, then yes it is permitted. Because this is only like hatmanah (insulation) with something that adds heat, which one also may not do on erev Shabbos. But again, because this is not hatmanah, this is only placed next to the pot, it’s not called hatmanah, as we learned earlier, al gabei (on top of) is not called hatmanah, so it is permitted.
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That’s the answer in chapter 4 in the laws of hatmanah, very quickly.
Do you sometimes do hatmanah?
I don’t do it so much. But a crock-pot warmer yes. There are people who hold that a crock-pot is hatmanah b’davar hamosif hevel (insulation with something that adds heat).
Okay.