The laws of leaving a pot of food on the fire into Shabbos 
When one desires to return a food to the fire before Shabbos without enough time for it to heat up by the time Shabbos begins, then in addition to the requirements discussed in this chapter, please refer to chapter 2 for other requirements, as will be explained there.
1. The reason for the Shehiyah restrictions:
In certain cases the sages decreed against leaving uncooked food on a fire from before Shabbos because if one were allowed to leave the food on the fire once Shabbos began, one may forget that it is Shabbos and stir the coals on Shabbos in order to finish the cooking. [See Q&A and footnote there regarding why this suspicion applies by today’s ovens]
2. The law by foods that one does not plan to eat until after Shabbos:
Even when one does not intend to eat from the food on Shabbos, all of the Shehiyah restrictions apply.
The reason for this is because: we are worried one may change his mind afterwards and decide to eat it on Shabbos, and now that he has the intention of eating it, he may come to forget and stoke the coals [in order] to finish the cooking.
3. The different types of ovens and their relative laws:
A. The laws in a case where the oven is no longer Yad Soledes:
If the oven has cooled off to the point that it is no longer Yad Soledes there, then it is permitted to leave [a pot of food] inside any type of oven, and certainly it is permitted to leave [a pot of food] on top of the oven or next to its outside, if it isn’t Yad Soledes in the place that one [wants to] leave it.
On Shabbos itself: [In fact if it isn’t Yad Soledes then] even on Shabbos itself it is allowed to put [a pot of food near the outside of the oven]. However to place [the pot] actually inside the Tanur or inside the Kirah is forbidden on Shabbos, even if the food is fully cooked, [and] even if the oven [had its coals] swept or covered, [and] even if it is not Yad Soledes [inside the oven], as will be explained later on [in The Laws of Chazara].
B. The Kirah Oven: 
What is a Kirah oven? A Kirah oven is made like a large pot in which a fire is lit inside it, on its bottom, and on its opening surface which is on top the pot is placed. It is long and short. On its top there is room to place two pots [as its top contains two holes, and one would place one pot over each hole].
What is its status regarding leaving food on it over Shabbos? If the fire [in the Kirah] was fueled with the waste of olives or with wood, then it is forbidden to put a [raw] dish on it before Shabbos in order to have it stay on the fire [and cook so it be ready] for [the] Friday night or Shabbos day [meal], if by the time the night [of Shabbos] begins the dish is still not cooked to the [same] point as the food [cooked by] Ben Drusaiy. (Ben Drusaiy was the name of a robber who would eat his food even though it was not still yet fully cooked.) [See Halacha 5B]
If however it is fueled with only twigs and straw, or [is even fueled with other types of wood and] has had its coals covered or removed, then it is permitted, as will be explained next.
The reason for the prohibition is: [because if one were allowed to place raw food on the fire, then] maybe one will [forget and] stir the coals and turn them over with a Machteh on Shabbos in order to finish the cooking.
Food which one plans to eat only the next day: Has the same status as food meant to be eaten on Friday night.
Fueled with twigs or straw: If it was fueled with straw or twigs then it is permitted to leave [even raw] food on it [from before Shabbos], even though it will not even be half cooked by the time Shabbos begins, and even if the Kirah has not been swept [of its coals] or [had its coals] covered.
The reason for this is: because the coals of the straw and twigs have no [real] tangibility left to them at all, and we are therefore not worried that one will come to stir the coals.
Ways to avoid the prohibition: Removing or covering the fire: If the oven is Gerufa, which means that all the coals have been swept, or if it is Ketuma, which means that the coals have been covered with ashes in order to diminish the ovens heat, [then it is permitted to leave even raw food on the oven before Shabbos, even though it will not be even 1/3 cooked before Shabbos].
How well the coals must be covered: It is not necessary to cover the coals until there is no recognizable fire in them at all; rather it is sufficient to cover it in any form even if the fire will still remain. [See Q&A regarding how to cover today’s stoves]
If the coals re-enflame: Once the coals have been covered even if the coals afterwards light up again by themselves, it is valid. [See Q&A regarding if the blech falls off, and if one may increase or lower the flame once the blech is on]
The reason for why the above removes the prohibition: is because since one revealed his intention from before Shabbos that he is no longer interested in the coals, we are no longer worried that perhaps he will stir the coals on Shabbos.
Coals that have dimmed by themselves: Coals that have dimmed are considered covered [and thus if all ones coals have dimmed there is no need to do anything to them and one may leave raw food on them from before Shabbos].
Leaving food near the oven:  One is allowed to place food near the oven, outside the wall of the oven, even if its fire inside has not been covered or removed, and even if the food has not been cooked to the point of Ben Drusaiy. This is allowed because we do not suspect one will stir the coals that are in the oven in order to speed up the cooking of the pot of food that is outside of it, as this stirring of the coals will not be of much help to quicken the cooking.
Leaving a pot directly on top of the coals: Is allowed in any case that Shehiyah is permitted. [See the laws of Hatmanah Chapter 1 Halacha 6 where this law is explained in more depth.]
Removing the pot from the coals on Shabbos in a case that it was placed directly on the coals: See “The Laws of Hatmanah” chapter 1 Halacha 7
Summary of the Kira oven:
The Kirah oven may not have food which is cooked less than the point of Ben Drusaiy placed on it before Shabbos unless either:
- It is fueled with only twigs and straw,
- Has had its coals covered
- Has had its coals removed.
- The coals have diminished on their own.
Placing near the oven: One is allowed to place food near the Kirah, outside by its walls, even if its fire has not been covered or removed.
C. The Tanur oven:
What is the Tanur oven? A Tanur is made similar to a large pot, wide at the bottom and narrow at the top. Due to this its heat is a lot more insulated inside of it than in a Kirah oven.
What is its status regarding leaving food on it over Shabbos? It is forbidden to even place [a pot] next to [the oven] if [the area which the pot is placed] is Yad Soledes. [This applies] even if [the coals in the oven] were swept or covered, and even if one used straw or twigs to fuel [the fire]. Certainly there is no need to mention that [it is forbidden to] place [a pot] on top or inside [this oven].
The reason for the above stringency is: since the heat [in this type of oven] is very hot, one will not remove his mind [from its flame, even if he covers it or removes most of it], and [thus] we suspect that he may stir the small fire [which remained after the coals were removed] even if this fuel is straw or twigs and has been covered by ash.
[The reason for] why we [suspect for the above, and thus] forbid [to leave the food, even] if one removed the coals of the Tanur is because: The sweeping [of the coals] only sweeps [away] the majority of the fire and its main strong point [and thus there is some fire which still remains], as it is impossible to sweep [out] the entire fire to the point that there isn’t even one spark left. [Thus since some fire inevitably remains in the oven, and] the heat [of this oven] is very hot, we suspect that perhaps he will stir those few sparks that remained in the oven, in order to flame up the fire [and thus speedy the cooking of his dish].
The Tanur oven may never have food left on or near it once Shabbos begins if the food has not yet been cooked to the point of Machel Ben Drusaiy, unless the area in which the pot is placed is not Yad Soledes, in which case one may leave the food even inside the oven.
D. The Kupach oven:
What is the Kupach oven? A Kupach is made similar to a Kirah with exception to that on its top there is only space for one pot. Due to this its heat is greater than that of the Kirah but less than the heat of a Tanur.
What is its status regarding leaving food on it over Shabbos? If the Kupach was fueled with straw or twigs, it has the same law as that of a Kirah which was fueled with straw or twigs [of which the law is that one may leave food on it before Shabbos even if the fire was not covered or removed]. [However] if it was fueled with olive waste or wood it has the same law as a Tanur for all matters.
E. The status of the ovens in the Alter Rebbe’s times:
Our ovens which open from the side, [since] their heat isn’t as strong as the Tanur of back in the day, and [it is also] not as hot as a Kupach, therefore it has the same laws as does a Kirah with regards to all matters.
The reason for why our ovens are not as hot as even a Kupach is: because [today’s ovens] are wider [on their top], and thus allow placing more than one pot [on top of them. Their heat is hence given more room to dissipate causing the oven to not be as hot].
F. The law by an oven which is plastered shut:
If one plastered clay around the covering of the opening of one’s oven there are no Shehiyah restrictions which apply in any of the cases, even by the Tanur oven, and even if the fire has not been removed or covered.
The reason for this is: because [in such a case] we are not worried one may trouble himself so much to break through the plaster in order to stoke the coals and still not remember that it is Shabbos. Therefore it is permitted to leave the food inside, whether it is roasting on coals, or whether it is cooking in a pot, whether it is completely raw, or whether it had already begun to roast or cook before Shabbos, and it did not yet roast or cook to the point of the food of Ben Drusaiy. [See Q&A regarding electrical appliances which do not have variation of temperatures]
- When one has plastered the opening of the oven shut regarding how it is permitted to break it on Shabbos, see Laws of Hatmanah Chapter 1 Halacha 8.
G. The law if the oven is not currently on but will eventually turn on, on Shabbos:
It is forbidden to place water close to Shabbos into a fixed pot that is inside the heater, unless there is enough time for it to heat half of its [desired] heat from before Shabbos. Now, even though his intention [in placing the water] is so that the pot not break, nevertheless since he also desires that this water heat up in order to use it to wash vessels with on Shabbos, as is common to do with this water, [therefore] we are worried that he may come to stoke the coals. (Now, although it is permitted to place food near an oven [even] if it is not swept or covered, as explained in chapter 253/3, nevertheless since this [set] pot protrudes onto the coals it is as if it is sitting on the actual coals.)
If one transgressed and placed water in the set pot of the heater before Shabbos: If one transgressed and placed water there, even if done inadvertently, and it was not heated to a 1/3 of its [desired] heat from before Shabbos, it is forbidden to even wash vessels with this water until enough time has passed after Shabbos to be able to heat it. (However if one placed it there before the oven was turned on, then it is possible that one could be lenient if this was done inadvertently.)
General summary of Ovens:
The allowance of leaving foods which have not been cooked to the point of Ben Drusaiy over a fire for the sake of Shabbos is dependent on the type of oven used.
It may never be left on a Tanur oven, irrelevant of form of fuel used. It may never be left on a Kupach oven that has been fueled with wood or olive waste. It may be left without restriction on a Kirah or Kupach oven that has been fueled with light fuel such as twigs and straw. If a Kirah oven is fueled with wood or olive waste, it may only be left there if the coals have been covered, removed, or dimmed. The covering of the coals which hence allows one to leave uncooked food on the fire is referred to as “Ketuma”.
What status of oven do our stoves and ovens have today?
All of our stoves [both gas and electric] and ovens today, being that they all have adjustable flames, have the same status as a Kirah which has been fueled with olive waste or wood, of which the law is that they must be covered in order to leave less than half cooked food on them before Shabbos.
Toaster oven: A toaster oven which only has room for one pot requires further analysis as to what status its oven should have; Kupach or Kirah.
What status of oven do Crock-pots, electric plates, and water boilers have today?
Adjustable temperatures: If they have adjustable temperatures they have the same status as stoves and ovens, and must be covered in order to leave less than half cooked foods on them before Shabbos.
One setting: If they have only one setting, either on or off and it is thus impossible to higher or lower the temperature, they never need to be covered. However there are Poskim which are stringent in this matter regarding water boilers. [To note that boilers with Shabbos setting are considered to have adjustable temperatures and hence the water must be cooked to the point of Ben Drusaiy before Shabbos begins.]
Attached to a timer: If the electric plate, crock pot etc is attached to a timer which turns on and off constantly on Shabbos, then even if the electrical device itself contains no adjustable temperatures seemingly it has the same status as an electric device that does contain adjustable temperatures, and hence must be covered in those cases where Ketumah is required.
How does one achieve “Ketumah” on today’s stoves, oven, crock-pot, and electric plate, in order to allow leaving uncooked food on them from before Shabbos?
Ovens: Some Poskim rule all the walls of the oven must be covered. Others rule it suffices to cover one wall, and the knobs which turn the flame. Practically one should avoid using an oven for less than half cooked foods. According to all one may use a tin oven insert which surrounds the food from all sides.
Shabbos oven: Those ovens which contain a Shabbos setting must likewise be covered in order to leave less than half cooked food on them before Shabbos. However there are Poskim which say that if it is placed on this setting it does not need to be covered.
Regarding opening an oven which is temperature based, see “The Laws Of Cooking” Halacha 15!
Electric plates with adjustable temperatures: Is to be covered with a sheet of tinfoil.
Crock pots with adjustable temperatures: Foil is to be placed between the outer cooker and the inner pot. However one is to beware not to place more than a single sheet of foil, as this can constitute a problem of Hatmanah/insulating. [One should also cover the knob of the crock pot.]
Boilers with adjustable temperatures: These systems do not contain a method of being covered, and thus must have their water heated up to 110 degrees from before Shabbos. [To note that boilers with a Shabbos setting are considered to have adjustable temperatures and hence the water must be cooked to the point of Ben Drusaiy before Shabbos begins.]
If the flame is turned on to its highest level, must it still be covered if the food is not half cooked?
Is there any minimum thickness which the blech must be?
No. However there are those which are stringent to use only a thick blech in order so it somewhat diminishes the heat of the flame.
May one cover the fire with tinfoil?
Ideally this is a legitimate form of covering, although there are opinions which doubt its validity. For this reason if one has nothing else to use but tinfoil he should try to fold the foil to make it thick, or to also cover the knobs of the stove.
May one use a blech that has holes in it?
If the holes are small, it is a valid covering. However if the holes are large enough to allow the flame to enter through it, then it is not considered a valid covering.
Must the entire area of the stove, or electric plate, or crock pot be covered?
Only the areas that are under the pots of food need to be covered. [Thus by a crock pot that the walls of the pot touch the entire inside, all of the inside must be covered, although as already explained in the previous question, if there are small holes, this does not pose a problem.]
Must the knobs of the stove etc be covered?
From the letter of the law it suffices to cover the flame alone. Nonetheless, there are Poskim which rule that the knobs should also be covered. According to all it does not suffice to only cover the knobs and not the flame.
If the blech fell off before Shabbos, must one replace it?
If one had already placed the food on it there is no obligation to replace it even if the food is not cooked.
May one adjust the flame after having placed the blech on it?
4. The law regarding leaving foods on forms of heat other than a stove and oven:
A. Leaving food by an open fire/Bon Fire:
One may place uncooked food near the fire before Shabbos even if the food has not yet been cooked to Machal Ben Drusaiy from before Shabbos. [However one may not place the food on the fire, or very near the fire, unless it has been cooked to the point of Ben Drusaiy.]
B. Leaving food on Tiberius springs from before Shabbos:
One is allowed to leave food over the hot springs of Tiberius from before Shabbos, having it cook over Shabbos. However to insulate it completely inside [the spring] is forbidden even from before Shabbos due to the insulating prohibition of, as is explained in chapter 326 [Halacha 3].
5. Cases in which the prohibition does not apply, even by a problematic oven:
A. Meat which is completely raw before Shabbos begins:
Completely raw meat may be placed right before Shabbos in a pot that is on an uncovered fire, even if the rest of the food in the pot has already begun cooking and is not yet half cooked, as the raw meat saves the food from the prohibition of leaving uncooked food on an uncovered flame.
The reason for why we do not suspect that one will come to stir the coals by raw meat, while by foods which have begun to cook we do suspect is: because since the food is now raw, one removes his mind from it until morning [Shabbos day], as by [Friday] night, the food will in any case not be ready even if he stokes the coals. As well there is no reason to suspect that he will stoke the coals so the food be ready for the Shabbos day meal, as since the food is on the fire from the night time until the next day, it is able to be cooked for Shabbos day even without stoking it at all.
When before Shabbos is the raw Meat to be placed on the fire? It may only be placed in the pot on the fire very close to the beginning of Shabbos, which is by sunset. [See Q&A].
The reason for this is: because if one places it there while it is still day [a while before sunset] then it has already cooked a little prior to the entrance of Shabbos, and one will thus have to remove it [from the oven] before dark [i.e. Shabbos begins], unless it is already cooked to the point of the food of Ben Drusaiy [½ cooked] before Shabbos comes in.
Which raw foods are allowed to be placed on the fire immediately before Shabbos? All the above allowance to place raw foods on the oven before Shabbos is only with regards to placing raw meat, as raw meat placed right before Shabbos is impossible to become fully cooked for the night meal. However other raw foods such as vegetables and the like are forbidden to be placed on a forbidden oven before Shabbos unless it has been cooked before Shabbos to the point of the food of Ben Drusaiy. [This prohibition includes also all types of raw legumes and cold water, as will be explained below.]
The reason for this is: because by other foods even if they are now raw, nevertheless if one were to stoke the coals it is possible for it to be fully cooked for the night [meal], and we thus suspect that maybe one will try speed up the cooking so it’s ready for the Friday night meal.
Raw legumes: One may not fill a pot with pounded wheat or lupines, or other types of legumes, and place it on top of a Kirah or inside of our type of Tanur which is not sealed with clay, if it is not swept or covered, unless there is enough time left during the day for it to cook to the point of the food of Ben Drusaiy, according to the custom. However if there is not enough time left in the day [for it to become cooked to the point of Ben Drusaiy], then it is forbidden to place it there even very close to Shabbos, [even] in a way that if this were to be meat then it would be permitted to leave meat there. [The reason for this is because by meat,] since the meat is completely raw close to Shabbos it will not be able to be ready for the night meal, however [by legumes it is forbidden as] all types of legumes are quick to cook, and can thus be ready for the night meal. This same law also applies to all types of vegetables [as explained in the 253/ 8]. [See Q&A]
The law if one transgressed and placed the legumes there: If one transgressed and placed it there, whether inadvertently or whether advertently, and it was not cooked to the point of the food of Ben Drusaiy from before Shabbos, then it is forbidden until enough time has passed after Shabbos to be able to cook them.
Completely raw meat [which is unable to become cooked in time for the Friday night meal-See Q&A below] may be placed right before Shabbos in a pot that is on an uncovered fire, even if the rest of the food in the pot has already begun cooking and is not yet half cooked.
If the raw meat will be fully cooked prior to daybreak on Shabbos day, does the above leniency still apply? 
It all depends on if the food will be ready by a time that it is commonly eaten by people in the home. For example if the food will be fully cooked in time for the main course of the Shabbos meal, as is usually the case when the raw meat has been cut small, then it is forbidden. If however it will only be ready by midnight, which is a time that no one plans to eat from it then it is valid. However if one is accustomed to taste the food towards midnight, then once again it loses its leniency.
If it is possible to raise the flame and thus cause the raw meat to be fully cooked by the night meal, does the above leniency still apply? 
No, as in such a case the suspicion that one may raise the flame to quicken the cooking fully applies.
When exactly before Shabbos does the raw meat have to be placed in the pot? 
It must be placed in close enough to Shabbos that the food will not be able to begin to cook before Shabbos, even if it will have the ability to warm up. This matter is very difficult to verify, and thus the above leniency of placing raw foods on an uncovered flame before Shabbos is difficult to place into application. Nevertheless from the letter of the law, as long as in ones estimation the meat will not begin to cook before Shabbos, it is allowed, if the other conditions explained in the previous questions are fulfilled. [Thus one who is accepting Shabbos early, may still follow this leniency as long as it will not begin to cook by the time that sunset arrives.]
Does the leniency to place raw foods on the flame apply to any other foods other then meat?
There are opinions which rule that legumes which require much time for them to cook may be placed on the fire right before Shabbos if they are raw. Others however argue that no such leniency applies by any food other than meat.
What is the definition of meat? Is chicken and other poultry defined as meat?
This matter requires further analysis.
B. The food has been cooked to the point of the food of Ben Drusaiy before Shabbos begins:
First Opinion: If before Shabbos commences the food has already cooked to the point of the food of Ben Drusaiy [see next Halacha for the exact definition], one is allowed to place the food on any type of oven. [See Q&A]
The reason for this is: because once it has become half cooked we are no longer worried he will stoke the coals, as even without stoking, the food is able to be fully cooked for the night meal being that it has already cooked half way from before Shabbos.
As well [another reason is] since the food has been [half] cooked from before Shabbos, the food is already [cooked enough to be] fit to be eaten in a pressing situation, [and we thus do not suspect that one will come to stir the coals].
Second Opinion: There are opinions which say that [the Shehiyah restrictions apply] even [by] food which has been cooked to the point of the food of Ben Drusaiy. [Furthermore it applies] even if it has been fully cooked but [further cooking will still make] it condense [in a way that] will benefit the food. Meaning [not that it will benefit the actual taste of the food per say but] that it’s [further cooking] is beneficial to the person [cooking it] and he is pleased with the [further] condensing of the food.[see footnote ]
The reason for why if the food can still condense it is prohibited according to this opinion is because: Perhaps one will stoke the fire on Shabbos to make it ready more rapidly, or in order so it will be condensed. For this reason it has the same laws, for all matters, just as if it had begun to cook [before Shabbos] but was not yet cooked to the point of the food of Ben Drusaiy, of which was explained above [that it has restrictions in regards to which ovens it may be placed on before Shabbos].
The final Halacha: The custom has already spread to be lenient like the first opinion [that if the food has been cooked to the point of Ben Drusaiy, then it may be left on any flame over Shabbos]. [See Q&A]
Is there room to require one to be stringent like the second opinion stated above that if further cooking of the food is beneficial we do not allow it to be left on an open flame?
Although as stated above the custom is not like this opinion, nevertheless today many are stringent to make sure that the food is fully cooked on Erev Shabbos, and in addition to this they still make sure that the flame is covered.
This is done in order to satisfy all existing opinions on the matter. [Nevertheless according to the Alter Rebbe there is no obligation for one to follow this stringency and at best it is only that there is room for stringency even in accordance to the Alter Rebbe’s opinion.]
If one accepts Shabbos early, must the food be half cooked before he accepts Shabbos, or does it suffice for it to be half cooked before sunset, the time that Shabbos actually begins?
As long as the food will be half cooked before sunset it may be placed on an uncovered fire before one accepts Shabbos.
Does all the food in the pot need to be half cooked, or does it suffice if most of the food in the pot is half cooked?
All the food in the pot needs to be half cooked, as otherwise the suspicion that one may come to raise the flame to hasten the cooking is still applicable to the minority part that is not yet cooked.
How does one measure if a food is half cooked?
Some Poskim say that it is determined in terms of the quality of the food, meaning that only if the food has reached half the point of its desired quality is it considered half cooked, even if it has already cooked for half the time that it needs. Other Poskim however say that it is determined by if the pot has stayed on the fire for half its required time.
The Kaf Hachaiym writes that it is determined as follows: As long as one is already able to eat the food at a pressing situation, such as when he is in a hurry, then it is considered half cooked.
C. What is the amount of cooking required for a dish to be considered cooked to the point of the food of Ben Drusaiy?/How much is Machel Ben Drusaiy?
Other Opinions: Others [however] say that it is half cooked [from the amount that people consider fully cooked].
The Final Ruling: Practically the law is that even though by Rabbinical prohibitions we rule leniently [when there is a dispute], nevertheless due to the severity of Shabbos one needs to be careful initially that from before Shabbos the food is cooked half the amount of its required cooking, [in a case that] none of the [above explained] leniencies apply.
However if after the fact [one had placed the pot on the fire without it having been ½ cooked] then the food is permitted in all cases, if it had cooked a third of its required cooking from before Shabbos [see Q&A].
May one be lenient by a pressing situation to leave the food on a revealed fire if it is only 1/3 cooked?
6. The laws of Shehiyah by foods that can be eaten raw:
Foods that are normally always eaten raw: Fruits that are eaten raw, such as apples and the like, are permitted to be baked very close to Shabbos, even if there is no time for them to become even half baked from before Shabbos.
The reason for this is because: Foods which are normally eaten raw and are not better when cooked, are no less different then a roast which has been roasted to the point of the food of Ben Drusaiy.
Foods which are only occasionally eaten raw: Fruits which are not eaten when they are raw, including even an onion which is at times eaten raw, nevertheless since it is not good to eat them raw, it is therefore forbidden to roast them too close to Shabbos to the point that it will not be able to cook to the point of Ben Drusaiy before Shabbos.
7. The laws of Shehiyah by Water:
All the Shehiyah regulations apply regarding placing water into a pot to heat before Shabbos. Thus if the fire is not covered, [which is the common case by all electric water urns, then if the urn has more than one heat setting,] one needs to place the water on the fire from before Shabbos with enough time left during the day for it to be able to heat up at least half its desired heat lechatchilah. [This is] according to our custom which is lenient like the opinions which allow Shehiyah when the food is cooked to the point of Ben Drusaiy. However according to those which prohibit to leave food on an oven unless it is fully cooked to the point that further condensing will damage it, then here too the water must be placed on the oven with enough time for it to fully heat up to the point that it condenses in a damaging way. [see Q&A]
Heating the water for purposes other than drinking: Whether one wishes to heat it for the purpose of drinking or for the purpose of cleaning vessels with it on Shabbos, all the Shehiyah restrictions apply.
Placing the water on the fire right before the beginning of Shabbos: One may not place the water on the flame [even] very close to Shabbos, as water heats up quickly, [and thus it can be ready for the night meal, and there is thus worry that one may come to stoke the coals to speedy its heating].
Why water has the Shehiyah restrictions if it can be drank without cooking? Now, although water can be drunk even cold [and thus it should be permitted as explained regarding raw fruits], nevertheless [since] it is not as good [to drink it cold] as is to eat fruits raw as explained above [therefore it is not allowed].
If one transgressed and placed water on the fire before Shabbos: If one transgressed and placed water there, whether inadvertently or whether advertently, and it was not heated to 1/3 of its [desired] heat from before Shabbos, then it is forbidden until enough time has passed after Shabbos to be able to heat it, just as is the law by all other cases.
Placing water before Shabbos in the set vessel that is inside the heater: It is forbidden to place water close to Shabbos into a fixed pot that is inside the heater, unless there is enough time for it to heat half of its [desired] heat from before Shabbos. Now, although his intention [in placing the water] is so that the pot not break, nevertheless since he also desires that this water heat up in order to use it to wash vessels with on Shabbos, as is common to do with this water, [therefore] we are worried that he may come to stoke the coals. (Now, although it is permitted to place food near an oven [even] if it is not swept or covered, as explained in chapter 253/3, nevertheless since this [set] pot protrudes onto the coals it is as if it is sitting on the actual coals.)
If one transgressed and placed water in the set pot of the heater before Shabbos:  If one transgressed and placed water there, even if done inadvertently, and it was not heated to a 1/3 of its [desired] heat from before Shabbos, it is forbidden to even wash vessels with this water until enough time has passed after Shabbos to be able to heat it. (However if one placed it there before the oven was turned on, then it is possible that one could be lenient if this was done inadvertently.)
What is the definition of half cooked water with regards to being allowed to leave it on an uncovered flame over Shabbos?
Half cooked water is approximately 50 Celsius [122 Fahrenheit]. By water left to be used for tea there is doubt as to whether this suffices, and perhaps it is required to boil before Shabbos.
In a time of need may one leave water on an uncovered flame if it is only 1/3 cooked? 
Does the water or oil that is inside a heater need to be half cooked before Shabbos, if it has adjustable temperatures?
Some Poskim rule it must reach half of its cooking point. Others however rule there is no need to do so. Practically it is best to initially be stringent and make sure that it is half cooked before Shabbos.
Does the water of a hot Mikveh need to be heated to its half way point before Shabbos?
If the Mikveh is to be used at the night of Shabbos [such as a women’s Mikveh], then it is to be pre-heated before Shabbos to its half way point. If this is not able to be done, one should lock the room that has the temperature settings, and this is considered as if he covered the fire [under a pot of food].
If the Mikveh is heated for the day [such as a men’s Mikveh] one is likewise to verify that the Mikveh reach its half way point before Shabbos, or at the very least lock the thermostat area. However then there are opinions which say that there is no need to verify that the water be preheated half way before Shabbos.
8. What is the law if one transgressed and left a pot over a flame in a case that it was prohibited to do so?
In all cases that it was explained that it is forbidden to leave food/liquid on the fire from before Shabbos if one transgressed and left it on the fire, even if this was done inadvertently, such as one forgot to remove it before Shabbos or that he thought it was allowed, nevertheless the food is forbidden for himself and for others to eat until enough time has passed after Shabbos for it to be able to cook.
One who does not have anything to eat other than cooked food which was left on the oven in a prohibited way: If one does not have anything else at all to eat on Shabbos besides for this food alone, then if it was left there inadvertently, he is allowed to eat it. [This is] due to the honor which is required to be shown for Shabbos, being that it is forbidden to fast on Shabbos.
General Summary of Shehiyah by Cooking
Is always permitted for all ovens in the following cases:
- One places a [large] piece of raw meat in a pot right before Shabbos.
- The food will be cooked to the point of Ben Drusaiy before Shabbos [½ cooked]
- The area that the food is being placed on is not Yad Soledes
- The oven is sealed shut with plaster.
If neither of the above four conditions are met, such as a food which is not yet half cooked and it does not contain raw meat, and one wants to place it by an area which is Yad Soledes, then it depends on the following:
- A Tanur fueled with any fuel and Kupach fueled with olive waste and wood: Is never allowed even near the oven.
- A Kirah: Is allowed in any of the following cases:
- Is fueled with straw or twigs.
- Its coals have been swept or covered.
- One is not placing the food on the oven but near the oven on its outside.
 As opposed to dough that is baked as well as foods that are roasted directly over the fire. These laws will be discussed in further chapters.
 However if one desires to initially begin cooking the food at this time, then only the requirements mentioned here are needed
 However to place on top of the oven is only permitted by a Kirah, and only if its coals have been swept or covered, as is explained in 253/21.
 This means that its length is longer than its width.[Shabbos 38b Rashi “Kupach”]
 Thus here the intention is that the food must be at least ½ cooked by the time Shabbos begins, as will be explained later on, as less then this amount of cooking even Ben Drusaiy would not eat.
 A tool used to stoke the coals.
 If the main idea regarding removing the coals is the removal of one’s mind from the fire, then why is there a difference in ovens regarding a case that one removed the coals?
It does not suffice to merely show that one is uninterested in the fire. As even if one placed signs and made promises that he is totally uninterested in the coals he would still be liable to follow all the Shehiyah restrictions. Hence merely showing lack of interest is not enough. Rather one must do an action which proves this lack of interest in a practical way. Hence one is required to diminish the fire to a point it would now be useless to stoke the coals, and only then are the restrictions lifted. Thus by a Tanur in which full removal of the coals is impossible, and in such an oven the fire can still be stoked to a cooking ability, therefore this method of showing un-interest does not work.
 Tzaruch Iyun why the Alter Rebbe here uses the term 1/3 cooked as opposed to Ben Drusaiy.
 1/2 cooked as will be explained in Halacha 5
 Shabbos Kehalacha Vol. 1 page 299
 Although electric stoves are covered by metal or fiber, and hence are physically similar to a gas stove with a blech, nevertheless since the metal is constantly there, without one doing any action, it does not serve as a reminder against raising the flame. In a similar case of doing Chazara to a heater in 253/26 Admur brings a dispute regarding if we consider the constant metal covering deemed as Ketumah, and he rules to be like the stringent opinion.
 There is a discussion amongst Poskim regarding if in truth the suspicion of “Shema Yechta” applies today by our ovens and stoves being that one can only higher the flame, while the suspicion back then was not that one may come to add more wood to the flame but that he may blow on the coals. The Igros Moshe [1/93] thus sides that today the suspicion is no longer applicable, however nevertheless even he rules that the flame must be covered, and so rule all the Poskim today. [Shabbos Kehalacha Vol. 1 page 296]
 On the one hand it has an opening on its side as does the ovens in Admur’s time. On the other hand there is only room for one pot on top, which is the main logistic ramification between the heat of the two ovens. See however Igros Moshe 4/74-26 which rules that if an oven is thermostat based, and it hence prevents the flame from becoming too hot, then it always has the status of a Kirah.
 Shabbos Kehalacha Vol. 1 pages 298-300
 Although electric plates, boilers and crock pots are covered by metal, and hence are physically similar to a gas stove with a blech, nevertheless since the metal is constantly there, without one doing any action, it does not serve as a reminder against raising the flame. In a similar case of doing Chazara to a heater in 253/26 Admur brings a dispute regarding if we consider the constant metal covering deemed as Ketumah, and he rules to be like the stringent opinion.
 Now although it is possible for one to remove the plug from the socket, nevertheless we do not suspect one may come to lower the flame, but rather only to raise it.
 Igros Moshe 4/74-23
 Perhaps this is for the reason mentioned by the questioner there, that one may come to remove water from the boiler on Shabbos prior to it being fully cooked, and doing so is forbidden due to hastening the cooking. However such a logic seems puzzling as we have no precedent that the Sages ever suspected for such a matter, and from the clear rulings it is implied that the opposite is the case.
 Authors note
 Such as one set up his electric plate to turn on for half hour intervals in order to keep his food warm, and not burn the food.
 As we suspect one may come to adjust the time in a forbidden way in order so the food be ready on time.
 The covering of the fire which hence allows one to leave uncooked food on the flame over Shabbos.
 Shabbos Kehalacha Vol. 1 pages 302-304
 Although this form of covering is not exactly similar to the concept of “sweeping or covering the coals” being that the latter effected a diminishing of the heat as opposed to the former, nevertheless many Poskim permit this to be used, including the Kaf Hachayim, Igros Moshe [1/93], and many of today’s Poskim.
Their reasoning is:
- It does somewhat diminish the heat.
- The main point is to show recognition that there is a decree, and this is accomplished also by placing a sheet of metal over the fire.
Other Opinions: The Ketzos Hashulchan [71/4] and Chazon Ish voice doubt regarding the validity of the Blech to achieve the state of Ketumah.
 Regarding why simply lowering the flame before Shabbos does not suffice as Gerufa: See Shabbos Kehalacha 8/14 that Gerufa means to completely remove the coals from under the pot and not to simply remove a portion of them.
 Shabbos Kehalacha page 312
 Chazon Ish 37/9, Minchas Yitzchak 3/28 and Igros Moshe 4/74-27
 Sheivet Haleivi
 This is similar to a tin box with an opening.
 This places the oven on a set temperature.
 As one can easily switch the oven from a Shabbos setting to a non-Shabbos setting, just as we suspect one may come to raise the flame. What the Shabbos setting is useful for is to allow removing food from the oven on Shabbos without worry that doing so may lead to the fire turning on, or staying on longer. [Shabbos Kehalacha 8/17]
 SSH”K 1 footnote 17
 It does not suffice to claim that a Shabbos setting serves as a reminder that one not raise the flame, as the Sages did not suffice with a mere reminder but rather with an act that diminishes the flame, as is evident from the concept of Ketumah. Perhaps however one can claim that placing it on a Shabbos setting diminishes the flame, and hence it can serve as a reminder.
 Shabbos Kehalacha pages 300-302
 Shabbos Kehalacha page 299
 Igros Moshe 4/74-25
 This is due to “Lo Plug” that we do not differentiate in the decrees of the Sages. However regarding diminishing the flame, this we do not suspect for. However by our gas ovens which are easily able to be diminished, perhaps the Sages would have likewise suspected for lowering the flame. [ibid]
 Shabbos Kehalacha Vol. 1 pages 304
 Shabbos Kehalacha Vol. 1 pages 304
 As at times tin foil is placed also during weekdays if one does not want the stove top to dirty, as well as that the foil burns off.
 Shabbos Kehalacha Vol. 1 pages 305
 Shabbos Kehalacha Vol. 1 pages 305-306
 Shabbos Kehalacha Vol. 1 pages 306
 So rules Shemiras Shabbos Kihilchasa, Igros Moshe [1/93] and other Poskim, based on the fact that the covering is only needed as a recognition.
 Igros Moshe ibid, and Sheivet Haleivi, in order so the area from where one raises the flame also have a recognition.
 Shabbos Kehalacha Vol. 1 pages 307-309
 As explained in Halacha 1
 Shabbos Kehalacha Vol. 1 pages 310
 Rav SZ”A [SSH”K 1 footnote 185]; See Shabbos Kehalacha 8/15 for an analysis on this subject.
 As doing so uproots the recognition made by the covering of the blech, as the entire purpose of the recognition is to show one is uninterested in the flame. Hence by adjusting the flame one uproots this recognition.
 253/23; 318/24
 318/24: There Admur explains regarding Chazara that “Kineged Hamedurah” means that the food may only be placed a slight distance away from the fire, however when placed very near the fire it is as if it has been placed on the fire. Seemingly this same ruling applies regarding Shehiyah, as is also evident from the wording in 253/23. However Tzaruch Iyun as there to the case is discussing Chazara before Shabbos and hence no real proof can be given.
 253/ 8
 Lupin is a plant which contains yellow seeds. These seeds are known as lupine beans and are a legume eaten in many Mediterranean countries.
 Meaning the Tanur in the Alter Rebbe’s time
 Meaning this alone suffices according to our custom, as opposed to other opinions which require it to be fully cooked, as will be explained in Halacha 5B.
 Therefore by meat it is permitted
 In contrast to other foods.
 As the raw meat saves the food from the prohibition of leaving uncooked food on an uncovered flame.
 Shabbos Kehalacha Vol. 1 page 324
 Shabbos Kehalacha Vol. 1 page 325
 Shabbos Kehalacha Vol. 1 page 327
 To note however that the Chazon Ish [37/22] learns that the definition of beginning to cook is when it reaches Yad Soledes. Seemingly on this basis the Shevisas Shabbos concludes that today in which we accept Shabbos early, with Tosefes Shabbos, this allowance is no longer applicable. However Rav Farkash rules as explained above for reasons written there in Shabbos Kehalacha.
 Ketzos Hashulchan 71 footnote 10
 Shabbos Kehalacha Vol. 1 page 330
 Second opinion in Michaber
 Rif/Rambam first opinion in Michaber
 The condensing of food that is being cooked causes its taste to be thicker and better, even though it is considered already fully cooked.
 Rav Farkash explains in Shabbos Kehalacha [Vol. 1 page 293] that the definition of further cooking being beneficial is solely dependent on the person cooking it. Meaning that if the person cooking wants the food to condense, such as that he desires it to be tastier, then it is considered beneficial, while if the person does not want it to condense, such as that he wants the portions to look nice and plump, rather than condensed and shriveled, even though doing so gives it a better taste, then nevertheless for him such further cooking is not considered beneficial, and would be allowed according to all.
 Shabbos Kehalacha Vol. 1 p. 320
 So rules Rav Farkash in Shabbos Kehalacha [Vol. 1 page 320], based on Mishneh Berurah and others. In the supplements [page 339] he as well seeks basis for this in the wording of the Alter Rebbe.
 Shabbos Kehalacha Vol. 1 pages 313-314
 This is inferred from the wording of the Alter Rebbe in Halacha 1 “if by the time the night [of Shabbos] begins the dish is still not cooked to the point of Ben Drusaiy. This is based on the ruling of the Magen Avraham 253/26. Regarding the question why the decree applies only by sunset and not beforehand by Tosefes Shabbos, Rav Akivah Eiger answers that only a single moment before Shabbos is Biblically required for Tosefes Shabbos. The Peri Megadim answers that the Sages only made their decree when the laws of Kareis and Sekilah apply on Shabbos, and thus since Tosefes Shabbos is only a positive command, it does not apply then.
 Shabbos Kehalacha Vol. 1 page 314
 Shabbos Kehalacha Vol. 1 page 314-316
 Sheivet Haleivi, and Kloizenberger Rebbe, based on Shut Mahrshag
 Chazon Ish, based on Peri Megadim
 The Rambam
 Meaning a 1/3 cooked from the amount of cooking that is in a fully cooked food.
 Rashi, Riy, Rashba, Maharam and other Poskim [Kuntrus Achron 2]
 Meaning that if the fire is not covered, and the meat is not completely raw, then in such a case one needs to Lechatchilah beware that the food be half cooked. However if the fire is covered or the meat is completely raw, then as explained above one need not worry at all about this.
 Lit Bedieved
 Seemingly this is coming to include even if the fire had not been covered. Vetzaruch Iyun
 Shabbos Kehalacha 1 p. 315
 This is based on the rule in Poskim that a pressing situation is equal to a Bedieved situation. So rules also Mishneh Berurah [253/38], Elya Rabah, and Shemiras Shabbos Kihilchasa 1/63.
 Meaning since they are eaten raw, they have the same logistics as do foods that have been ½ cooked, in which we rule that they may be left on the fire Erev Shabbos without restriction.
 Meaning that they are not as tasty.
 See above Q&A 3
 Meaning half of its boiling point [100 Celsius], which is thus 50 Celsius. See Q&A1
 Bedieved, or in a time of need it suffices if it has/had enough time to cook 1/3 of its desired heat before Shabbos.
 Meaning that according to the stringent opinion, [as opposed to our custom] the water must be heated to the point that further cooking damages it, such as that it causes it to evaporate.
 Tzaruch Iyun why the Alter Rebbe here uses the term 1/3 cooked as opposed to Ben Drusaiy.
 Tzaruch Iyun why the Alter Rebbe here uses the term 1/3 cooked as opposed to Ben Drusaiy.
 Shabbos Kehalacha Vol. 1 pages 317-319
 There are two options: Either half of Yad Soledes [45 Celsius, or 110 Fahrenheit], which is 55 Fahrenheit or half of its boiling point [100 Celsius, or 212 Fahrenheit] which is 50 Celsius [122 Fahrenheit].
The Igros Moshe strongly proves like the latter, as if the water is only a third [or half] of Yad Soledes then it is barely even warm, and thus it’s not logical to say it refers to Yad Soledes. Rather he explains that it refers to a third [half according to us] of the amount that a person usually desires his water to heat up to, which is half of boiling point.
Rav Farkash supports this ruling and infers it from the wording here of the Alter Rebbe “half of its heat” as opposed to half of its “cooking”.
The Tehila Lidavivd learns similarly in the Alter Rebbe that it refers to half of one’s desired heat for the water.
 The Ketzos Hashulchan questions whether if it suffices if water heated for tea is not boiled before Shabbos. This is because a person does not really want to use the water until it is boiling, and it is thus not considered fit to eat prior boiling point. He leaves this query without a conclusion. Rav Farkash however suggests in the supplements [page 338] that even in such a case it is allowed.
 Shabbos Kehalacha 1 p. 315
 This is based on the rule in Poskim that a pressing situation is equal to a Bedieved situation. So rules also Mishneh Berurah [253/38], Elya Rabah, and Shemiras Shabbos Kihilchasa 1/63.
 Shabbos Kehalacha Vol. 1 page 332
 Sheivet Haleivi
 Rav Shlomo Zalman Aurbach and other Poskim
 Shabbos Kehalacha Vol. 1 page 332-333
 Rav Shlomo Zalman Aurbach
 As is the simple understanding of the SHU”A 253/29; 254/14-15, and as is clearly ruled in 326/1. So is also the custom of Rav Wosner to be stringent in the Mikveh under his ruling.
 Mahrsham 229; Sheivet Haleivi 7/32
 Mahrsham rules it is allowed being that one does not plan to use the water until the next morning and is thus similar to raw meat, and because in any event it is forbidden to heat the Mikveh too much due to the prohibition of bathing in hot water. These arguments however are not relevant today being that we are accustomed to immerse in hot water. Furthermore Admur clearly rules that we suspect for stoking the coals even one leaves the food for the next day, and why should we differentiate between food and water of the Mikveh. Just like one may come to change his mind and decide to eat the food at night, perhaps one will desire to immerse in the Mikveh at night, past sunset on Shabbos. In any event the Mahrsham concludes that the fire [or area of raising the temperature] is to be covered.
 Meaning if it takes 90 minutes to make such a dish, then one must wait until 90 minutes after Shabbos to be allowed to eat it.
 254/ 8