Daily Halacha: Salting Hot Foods on Shabbos: Halachic Considerations and Guidelines (Thursday, 26th Teves)

Salting Hot Foods on Shabbos: Halachic Considerations and Guidelines:

1. Introduction:

The act of adding salt to food is one of the most basic steps in food preparation and consumption. Often, a dish may not contain enough salt to suit one’s taste, prompting the desire to sprinkle additional salt onto the food. While this seems simple, the question of salting food on Shabbos is far from trivial. It raises significant halachic concerns, particularly regarding the prohibition of cooking (bishul) on Shabbos.

The issue with salting even cold foods:[1] Interestingly, this discussion is not limited to hot foods alone. The principle applies to cold foods as well, prompting a substantial chapter in halachic literature that addresses the issue of salting foods on Shabbos. This is due to concerns regarding transgression of the prohibition of Meabeid, particularly when salt alters the natural state of certain items, such as specific vegetables. In this article, we will focus specifically on salting hot foods and whether doing so constitutes a violation of the cooking prohibition. The method of salting and items that may be salted are of course limited to the laws of Meabeid that apply even to cold foods. However, in general, most foods that are served hot do not have a prohibition of Meabeid associated with adding salt to them, either due to it containing liquids which nullifies the power of the salt, or due to them being foods that do not have a Mebaied prohibition applicable to them, as explained in the corresponding chapter.

The Core Halachic Questions and Factors associated with salting hot foods: The core halachic question associated with salting hot foods on Shabbos is whether adding salt to hot food on Shabbos transgress the prohibition of cooking with regards to the salt. To answer this, we must examine several key factors:

1. Temperature of the Food: Which temperatures are considered problematic for salting? Does the food need to be boiling hot, Yad Soledes, or is warm enough to pose a concern?
2. The Status of the Vessel – Kli Rishon, Sheiyni, Shelishi: Does Halacha differentiate between salting a hot food that is in a Kli Rishon, the original pot in which the food was cooked, versus a Kli Sheni, a secondary vessel into which the food was transferred, versus a Kli Shelishi, a third vessel into which the food was transferred
3. The Case of a Davar Gush: A Davar Gush is a solid item, such as a piece of meat or potato. Being that solids retain heat differently than liquids, does the permissibility of adding salt to a Davar Gush follow the same laws as adding salt to a food that is found in a Kli Sheiyni or Kli Shelishi.

4. The Status of the Ladle and Subsequent Bowl: If a ladle is used to transfer soup from a Kli Rishon into a bowl, what is the halachic status of the bowl? Does the ladle act as an intermediary, making the bowl a Kli Shlishi, or does it retain the status of a Kli Sheni? How does this impact the permissibility of adding salt?
5. Type of Salt: Is there a difference between raw salt, such as rock salt that has never been cooked (i.e. Himalayan Pink Salt), and salt that has already been cooked or processed, such as typical table salt? Does previously cooked salt mitigate the concern of cooking on Shabbat?
6. If One Transgressed: What is the halachic status of the food if salt was added in violation of the prohibition? Are there corrective measures or consequences?

The General law:

As stated above in the introduction the core issue in determining whether one may add salt to hot food on Shabbos depends on several interrelated factors: the temperature of the food, the status of the vessel—whether it is a Kli Rishon, Kli Sheni, or even a Kli Shlishi—the nature of the food itself, distinguishing between liquids and solid items known as Davar Gush, and the type of salt being used, whether raw rock salt or processed, pre-cooked table salt. Each of these elements carries unique halachic implications, as the prohibition of cooking (bishul) on Shabbat may apply differently based on these variables. In the following discussion, we will analyze each of these aspects in detail and outline the practical rulings that emerge from the classical sources and contemporary authorities.

1. The Temperature of the Food – Yad Soledes versus Below:[2] The issue of adding salt to hot food on Shabbat applies only if the food has reached the temperature of Yad Soledet Bo, which is approximately 110°F (45°C). ^[3] This is defined as a level of heat that cannot be comfortably tolerated by the touch of a finger—if the finger cannot remain on the food due to its heat, it is considered Yad Soledet Bo.[4] If the food is below this temperature, it lacks the ability to cook, and therefore, in all cases, it is permitted to add salt to the food^[5], so long as it is no longer on the fire or heating element. However, a stringency exists regarding a Kli Rishon, the original pot that was on the fire, by which we rule that it is proper for one to not add anything uncooked, including spices, into a Kli Rishon, even if it has cooled below Yad Soledet Bo.^[6] Nevertheless, regarding salt, there is greater room for leniency in this matter, to allow adding salt to a Keli Rishon that is no longer Yad Soledes without any discouragement[7], although perhaps even here we can say that one who is stringent is blessed.[8]
2. The Type of Salt: Raw Rock Salt vs. Pre-Cooked Table Salt:[9] According to all opinions, adding raw rock salt—or any salt that has never undergone prior cooking—into liquids at a temperature of Yad Soledet Bo raises a concern of bishul (cooking), subject to additional factors we will address later. In contrast, pre-cooked salt, which includes virtually all commercially produced table salt that undergoes a dehydration process involving cooking, is the subject of debate regarding whether the principle of ein bishul achar bishul (no cooking after cooking) applies.[10] Practically, while those who are lenient have authorities upon whom to rely, the Alter Rebbe concludes that one should adopt stringency and refrain from distinguishing between cooked and raw salt.[11] One who follows this stricter approach is considered praiseworthy.[12] This applies even if the salt will not dissolve, nevertheless, it is proper to be stringent.^[13] [To note, that many modern salts today, including table salts are not considered pre-cooked; they are simply dried in an oven or through the sun, not boiled or fully cooked, and hence would not be subject to any Bishul Acher Bishul leniencies.[14]]
3. Adding Salt to a Keli Rishon:[15] According to all opinions, it is biblically forbidden—due to the prohibition of cooking (bishul)—to add salt to a Kli Rishon that is on the fire and is at the temperature, or will reach the temperature, of Yad Soledet Bo.[16] However, if the pot has been removed from the fire, the matter becomes subject to debate among the Poskim: some Poskim[17] permit adding salt of any type to a Keli Rishon that is off the fire even when it remains Yad Soledet Bo, while other Poskim[18] forbid it [with previously uncooked salt, and one is to be stringent with even cooked salt, as stated above]. Practically, the accepted ruling is to be stringent, and this is the prevailing custom[19], as the Poskim[20] stated that one who is stringent is blessed.
4. Adding Salt to a Keli Sheiyni:[21] There exists a major dispute amongst the Poskim[22] regarding the cooking status of a Kli Sheni and whether uncooked foods may be placed inside it. Practically, we rule that one should be stringent with all uncooked foods, with the exception of spices and certain liquids, which may be placed in a Kli Sheni [provided it is not extremely hot—since excessive heat renders it similar to a Kli Rishon^[23]].^[24] Despite this leniency, some Poskim[25] rule that salt is be an exception to the spice category and could cook even in a Kli Sheni, and hence it is forbidden to place salt even in a Keli Sheiyni. As we concluded previously, this stringency would apply even if the salt was previously cooked. Practically, one who is stringent and refrains from placing any type of salt in a Kli Sheni is praiseworthy[26], and indeed the prevailing custom is to avoid doing so. As stated above, this applies to all types of salt, whether pre-cooked or raw.
5. Adding Salt to a Keli Shelishi, or Iruiy Keli Sheiyni:[27] It is permitted without restriction to add salt to a Kli Shlishi, or pour onto it from a Keli Sheiyni, as a third vessel does not possess the capability to cook foods, with the exception of items classified as kalei habishul—foods that cook extremely easily—among which salt is not included.[28] Therefore, all types of salt, whether rock salt, previously cooked salt, or dissolvable salt, may be added to a Kli Shlishi without concern. [Nonetheless, even here, a person of desires to be stringent by a Keli Shelishi has upon whom to rely, although he is not the rule this way for others.[29]]
6. Adding Salt to a bowl of hot food [i.e. Soup]:[30] Although the halachic status of a ladle or serving spoon is debated^[31]—whether it retains the status of a Kli Rishon or is downgraded to a Kli Sheiyni—practically, one may be lenient and consider the bowl into which the ladle poured as a Kli Shlishi.[32] This leniency is especially relevant regarding salt, since even in a Kli Sheni abstaining from adding salt is merely a matter of stringency and blessing; therefore, with food in a Kli Shlishi served via a ladle, one may certainly be lenient. However, this applies only to liquid foods such as soup. Solid foods, when transferred into a bowl, fall under the category of Davar Gush, which will be addressed next.
7. Davar Gush – Adding salt to a hot solid food (i.e. thick cholent or rice):[33] The halachic status of a hot solid food (Davar Gush) that is at Yad Soledet Bo is (Davar Gush) that is at Yad Soledet Bo is debated among the Poskim. The question is whether such a solid becomes downgraded when placed into subsequent vessels—such as a Kli Sheni or Kli Shlishi—and follows the same leniencies as regular liquids, or whether it retains its original Kli Rishon status as long as it remains at Yad Soledet Bo, regardless of how many vessels it enters. Practically, although many authorities are stringent and treat Davar Gush as retaining its cooking power[34], there is significant room for leniency regarding salt, which itself is under debate even in a Kli Rishon. Accordingly, one is not required to be stringent about placing salt onto solid foods that have entered a Kli Shlishi, although one who adopts stringency has upon what to rely. However, this only applies to solid foods that have been removed with a spoon or spatula and then placed onto the plate, however, if it was taken from a Kli Rishon with a fork then retains its original status until it is placed into an actual vessel. Once transferred onto a plate or bowl, it is considered at most a Kli Sheni even according to the lenient opinion, and hence in this case one who is stringent to not place salt onto the food is blessed just as we apply to every Keli Sheiyni.^[35]
8. If One Already Added Salt (Bedi’eved):[36] Although the general rule is that one who transgresses the prohibition of bishul may not benefit from the food on Shabbos, this applies only when the act was forbidden according to all opinions. If, however, there are authorities who permit the action even initially, the food remains permissible to eat on Shabbat.^[37] Accordingly, if one added any type of salt to a Kli Sheni, the food remains permitted. Furthermore, even if the salt was added to a Kli Rishon while it was still on the fire—where all opinions agree that doing so is prohibited—many Poskim rule that spices are an exception to the general rule, and therefore the food remains permitted even bedi’eved.^[38] However, there are opinions^[39] which argue and prohibit the food even by spices.^[40]

The practical Ruling:

On Shabbos, adding salt to food depends on the vessel and temperature: if the food is below Yad Soledet Bo (≈110°F / 45°C), it is permitted in all cases once off the fire, even in a Keli Rishon. Adding salt to a Kli Rishon on the fire is strictly forbidden. Furthermore, even in a Keli Rishon that is off the fire, and even in a Kli Sheni, the prevailing custom is likewise to refrain from adding any type of salt, though leniency exists amongst the Poskim, especially regarding precooked salts. Practically, one who is stringent  is blessed. In a Kli Shlishi or when pouring from a Kli Sheni, it is permitted without restriction to add salt of any kind. A bowl served via a ladle is treated as a Kli Shlishi for liquids, so adding salt is allowed, while solid foods (Davar Gush) in a Kli Shlishi do not require stringency, though one who is strict is praiseworthy. If salt was added improperly (bedi’eved), the food remains permitted in most cases, even when added to a Kli Rishon on the fire, as many authorities allow eating it.

Examples of Adding Salt on Shabbos:

• Soup in the Original Pot (Kli Rishon): If the soup is still in the pot that was on the fire and is at Yad Soledet Bo, it is forbidden to add salt. Even if the pot is off the fire but still very hot, the custom is to be stringent and avoid adding salt.
• Soup in a Bowl (Kli Shlishi): After serving soup into a bowl using a ladle, the bowl is considered a Kli Shlishi. It is permitted to add any type of salt without restriction.
• Cholent in the Original Pot (Kli Rishon): If the cholent is still in the original pot at Yad Soledet Bo, one is not to add salt.
• Liquid Cholent in a Bowl (Kli Shlishi): Once served into a bowl, liquid cholent is treated like soup in a Kli Shlishi, and adding salt is permitted.
• Solid Cholent (Davar Gush) in a Bowl: Even in a bowl, many poskim treat Davar Gush as retaining heat and cooking power if it is still Yad Soledes. However, practically, one may be lenient and add salt if the cholent was served with a serving spoon, though one who is stringent is praiseworthy. This stringency only applies so long as the food is still Yad Soledes.
• Rice in the Original Pot (Kli Rishon): If the rice is still in the pot and at Yad Soledet Bo, one is not to add salt.
• Rice in a Bowl (Kli Shlishi): Even in a bowl, many poskim treat Davar Gush as retaining heat and cooking power if it is still Yad Soledes. However, practically, one may be lenient and add salt if the rice was served with a serving spoon, though one who is stringent is praiseworthy. This stringency only applies so long as the food is still Yad Soledes.
• Mashed Potatoes in a Bowl: Even in a bowl, many poskim treat Davar Gush as retaining heat and cooking power if it is still Yad Soledes. However, practically, one may be lenient and add salt if the mashed potatoes was served with a serving spoon, though one who is stringent is praiseworthy. This stringency only applies so long as the food is still Yad Soledes.
• Hot Fish or Meat or Chicken with Gravy Served on a Plate: When hot fish, meat, or chicken is served on a plate together with gravy, the gravy gives the food the status of a Kli Shlishi, similar to soup. Therefore, it is permitted to add salt without restriction.
• Hot Fish or Meat or Chicken without Gravy Served on a Plate: When served without gravy, the food is considered a Davar Gush (solid item) and retains significant heat. Practically, one may be lenient and add salt in this case if the food was served with a serving spoon, although one who is stringent and refrains from doing so is praiseworthy. However, if the food was served using a fork then according to all it is proper to be stringent and not add salt so long as the food is still Yad Soledes, as we apply to every Keli Sheiyni that one who is stringent is blessed.
• Adding Salt to Kugel: If a piece of hot kugel at Yad Soledet Bo is taken from the original pot (Kli Rishon) and placed onto a plate using a fork, then even according to the lenient opinion it retains the status of a Kli Sheni and not a Kli Shlishi, and therefore salt should not be added to it, just as we rule regarding all Kli Sheni. However, if the kugel is transferred with a spoon or spatula, one may follow the leniency applied to Davar Gush as mentioned earlier, and adding salt in such a case is permitted, though one who is stringent is praiseworthy. This stringency only applies so long as the food is still Yad Soledes.

Summary

Adding Salt to Hot Food on Shabbos is Permitted in Any of the Following Scenarios:

1. When the food is below Yad Soledet Bo (approximately 110°F / 45°C).
2. When the food is in a Kli Shlishi (third vessel), even if served with a serving spoon and even if it is a Davar Gush.
3. When pouring from a Kli Sheni into a Kli Shlishi.

Table

[1] For further details and comprehensive halachic analysis, please refer to our corresponding sefer, The Shabbos Kitchen, Chapter 15

[2] See Admur 318:9; 11; 24; 29; Michaber 318:14; Shabbos 40b; For further details and comprehensive halachic analysis, please refer to our corresponding sefer, The Shabbos Kitchen, Chapter 6 Halacha 2!

[3] See Igros Moshe 4:74 ; Minchas Yitzchak Likkutei Teshuvos 29; Rav SZ”A in Minchas Shlomo 1:91; SSH”K 1 footnote 3; For further details and comprehensive halachic analysis, please refer to our corresponding sefer, The Shabbos Kitchen, Chapter 6 Halacha 2!

[4] Vayeishiv Moshe 178; Hilchasa Rabasa Leshabbaso in name of Chasam Sofer that he would check with his finger; Yeshuos Chochmah 80; Minchas Yitzchak 5:127; Birur Halacha [Zilber] 318; ; Piskeiy Teshuvos 253:1; See Rashi Shabbos ibid “His hand goes backwards due to fear that he may get burnt” ; For further details and comprehensive halachic analysis, please refer to our corresponding sefer, The Shabbos Kitchen, Chapter 6 Halacha 2!

[5] See Admur 318:9; 11; 24; 29; Michaber 318:14; Shabbos 40b

^[6] Admur 318:17 “It is proper to abstain from placing spices in a Keli Rishon even if it is no longer Yad Soledes”; M”A 318:28, based on Yerushalmi Shabbos 3:4; Iglei Tal Ofeh 12; Kaf Hachaim 318:5; Shevisas Hashabbos Mivasehl 47; Piskeiy Teshuvos 318:46

The reason: This is done in order to distance [oneself] and make a fence around the matter [so that one not come to transgress the prohibition of placing spices when it is Yad Soledes]. [Admur ibid]

Other Opinions: Some Poskim rule that once the Keli Rishon is no longer Yad Soledes then one may place any food in it [that does not contain a Molid prohibition].  [M”B 318:64 and Shaar Hatziyon 318:89 in name of Elya Raba, and Shach and Peri Chadash[

[7] See 1st and Stam opinion in Admur 318:17 as rules Michaber 318 “Some Poskim rule that [all] salt [even if never previously cooked, i.e. rock salt] is allowed to be placed inside [a Keli Rishon that is Yad Soledes] that has been removed from the fire, as salt requires a long amount of cooking similar to ox meat and does not cook unless it is on a fire.”; Now, although Admur records a second stringent opinion and concludes that one who is stringent even by a Keli Sheiyni is blessed, as brought in the next footnote, nevertheless, this is only with regards to if the temperature is Yad Soledes, however, if the temperature is below Yad Soledes, then it would be a very far-fetched stringency, and a stringency upon a stringency for one to be advised to be careful even in such a case; See Piskeiy Teshuvos 318 footnote 414 for a similar argument

[8] See 2^nd opinion and final ruling in Admur 318:17 regarding non-precooked salt [i.e. rock salt] “[However] there are opinions which say that salt only requires a slight amount of cooking and is thus forbidden to be placed even in a Keli Sheiyni so long as it is Yad Soledes. One who is strict will be blessed.” Now, although we concluded in the footnote above that this opinion is referring to a case that the liquid is Yad Soledes, nevertheless, certainly one who chooses to be stringent even by a Keli Rishon which is less than Yad Soledes is praised, even though it is not a requirement for suggested practice. See Kaf Hachaim 318:5; Shevisas Hashabbos Mivasehl 47; It is noteworthy that although the status of a Kli Sheni is subject to a three-way debate regarding its cooking power—and the general ruling permits adding spices to a Kli Sheni—many authorities adopt stringency specifically concerning salt. Both the Alter Rebbe and the Rama conclude that one who refrains from adding salt to a Kli Sheni is praiseworthy and receives a blessing. This demonstrates that even in a case involving multiple doubts—such as whether foods cook in a Kli Sheni at all, and whether salt is capable of cooking even in a Keli Rishon—there remains room for stringency, and one who does so is indeed blessed.

[9] Siddur Admur regarding both rock and sea salt “One may not be lenient regarding our salt that although it is previously cooked, nevertheless since it dissolves upon re-cooking one may not be lenient with it any more than the salt of the old days [which was not previously cooked] based on the difference of opinions mentioned in Shulchan Aruch of which there are opinions which hold that it is forbidden to even place it in a Keli Sheiyni that is Yad Soledes, and one who is stringent is to be blessed.”; 2^nd opinion and final ruling in Admur 318:17 regarding non-precooked salt [i.e. rock salt] “[However] there are opinions which say that salt only requires a slight amount of cooking and is thus forbidden to be placed even in a Keli Sheiyni so long as it is Yad Soledes. One who is strict will be blessed.”; Conclusion of Admur 318:18 regarding precooked salt [i.e. sea-table salt]: “Nevertheless one who is stringent in this just like by other salt [which is not cooked], will be blessed.”; Levush 318; Elya Raba 318:24; See P”M 318 A”A 31; Piskeiy Teshuvos 318 footnote 410

Other opinions in Admur regarding even rock salt [i.e. not-precooked]: Some Poskim rule that [all] salt [even if never previously cooked, i.e. rock salt] is allowed to be placed inside [a Keli Rishon that is Yad Soledes] that has been removed from the fire, as salt requires a long amount of cooking similar to ox meat and does not cook unless it is on a fire. [1^st opinion in Admur 318:17 as rules Michaber 318:9.]

[10] Lenient: Some Poskim rule that according to all opinions, precooked salt may be placed into a Keli Rishon. [Admur 318:18; M”A 318:31; M”B 318:71; Shaar Hatziyon 318:96] In the Shulchan Aruch, after Admur records the ruling of the stringent opinion in 318:17 who prohibits placing salt even in a Keli Sheiyni, he writes in 318:18 “All the above refers to salt which has not been [extracted through] cooking, however salt which has been extracted through cooking water is permitted to be placed in a Keli Rishon according to all opinions being that there is no [prohibition to] cook an already cooked [food] that is dry even if it dissolves through this second cooking as was explained above.”]

Stringent: According to the ruling of Admur in his Siddur ibid, foods which dissolve contain a cooking prohibition and thus according to the second opinion in 318:17, one is to be stringent not to place even previously cooked salt, even into a Keli Sheiyni. Even in his Shulchan Aruch in 318:18 Admur concludes as he does in his Siddur that “Nevertheless one who is stringent in this just like by other salt [which is not cooked], will be blessed.” Thus, there is no practical difference between Admur in his Siddur or Shulchan Aruch in this regard!

[11] Admur in Siddur ibid

[12] Admur 318:18

^[13] Shabbos Kehalacha p. 158

[14] Madrich Eida HaChareidit; Maor Hashabbos 13:10; Piskeiy Teshuvos 318:45; See P”M 318 A”A 31; Typical table salt is produced through a vacuum‑evaporation process in which brine is heated and boiled to form highly refined sodium chloride crystals, meaning it is effectively “cooked” during manufacturing; however, some table salts are made from solar‑evaporated or minimally processed sources that are not boiled and are instead simply washed and oven‑dried, so whether a given table salt is “cooked” ultimately depends on the brand and the production method it uses.

[15] See Admur 318:17

[16] Admur ibid “salt is allowed to be placed inside a pot that has been removed from the fire, as salt requires a long amount of cooking similar to ox meat and does not cook unless it is on a fire.”; Michaber 318:9; Rambam  Shabbos 22:6 “A large fire”; Rashi Shabbos 42b; Ran Shabbos 20a; Beis Yosef 318

Other Opinions: See Chidushei Tzemach Tzedek Shabbos 41b who argues that salt does not cook even in a Keli Rishon that is on the fire

[17] 1st opinion in Admur 318:17 “Some Poskim rule that [all] salt [even if never previously cooked, i.e. rock salt] is allowed to be placed inside [a Keli Rishon that is Yad Soledes] that has been removed from the fire, as salt requires a long amount of cooking similar to ox meat and does not cook unless it is on a fire.”; Michaber 318:9; Rambam  Shabbos 22:6; Rebbe Chiyah and Rav Nachman in Shabbos 42b; Ran Shabbos 20a; Beis Yosef 318

[18] 2nd opinion and final ruling in Admur 318:17 regarding non-precooked salt [i.e. rock salt] “[However] there are opinions which say that salt only requires a slight amount of cooking and is thus forbidden to be placed even in a Keli Sheiyni so long as it is Yad Soledes. One who is strict will be blessed.”; Rama 318:9; Rebbe Chiyah Shabbos 42a in Lishna Kama; Tosafus Shabbos 42a; Mordechai Remez 308; Hagahos Ashri

[19] Piskeiy Teshuvos 318:45

[20] See Admur ibid in 318:17 and in Siddur even regarding a Keli Sheiyni “One who is strict will be blessed”; Rama ibid; Tosafus ibid; Mordehai ibid; Hagahos Ashri ibid; Kaf Hachaim 318:6; Nimueki Orach Chaim 318:1 in name of his father the Darkei Teshuvah that who wants to lose the blessing of the Rama; Piskeiy Teshuvos 318:45

[21] See Admur 318:12; For further details and comprehensive halachic analysis, please refer to our corresponding sefer, The Shabbos Kitchen, Chapter 6 Halacha 13!

[22] First opinion-Rabbinically forbidden: Solid foods that have not been [fully] cooked before Shabbos, are Rabbinically forbidden to be soaked in a Keli Sheiyni being that it appears like cooking. [1^st opinion in Admur 318:11; 1^st opinion in Tosafus Shabbos 39a; M”A 318:15 and 19]

Second opinion-Completely permitted: There are opinions which allow any food, [even] if it has not yet cooked, to soak in a Keli Sheiyni [even if the Keli Sheiyni] is Yad Soledes. [2^nd opinion in Admur 318:11; 2nd opinion in Tosafus Shabbos 39a; second opinion in Michaber 318:5; M”A 318:19]

Third Opinion-Possibly Biblically forbidden: There is an opinion [Yireim] which questions and suspects [that there is] a sin offering liability [involved]  [in cooking] in a Keli Sheiyni that is Yad Soledes, being that there are delicate foods that cook even in a Keli Sheiyni and we are not experts [as to which foods are delicate and which are not], and [thus] perhaps food such as bread is also considered delicate in this regard and it cooks in a Keli Sheiyni which is Yad Soledes [and one is thus liable].  This doubt as well applies by other foods. [3^rd opinion in Admur 318:12; brought in Taz; Yireim; M”A 318:18; First opinion in Michaber 318:5]

[23] Implication of Admur 318:20 and Michaber 318:11 “A bathtub that is filled with hot water, even though it’s [water is considered] a Keli Sheiyni, [nevertheless] it is forbidden to pour cold water [or any other uncooked food] into it [just like a Keli Rishon]. The reason for this is because since the hot water in it is meant for washing it can be assumed that it is very hot and [will thus] cook the cold [water] which gets mixed into it.”; Admur 318:23 “[Furthermore] it is forbidden to place [a bottle] even into a bathtub that had drawn into it the hot springs of Tiberius directly from the spring, [such as one channeled the spring water into the tub], because it [a tub] is Rabbinically considered like a Keli Rishon. Rather one should enter water from the tub into a second vessel and then place [the bottle] into it.”; Tur 318; M”A 318:34; Levushei Serud ibid; Tzemach Tzedek Mishnayos 3:5, as explained in Ketzos Hashulchan 124 footnote 31; M”B 318:76; and 48; Chayeh Adam Shaar Mitzvas Haaretz 2:9; Rosh Yosef

Other opinions: Some Poskim learn that the bathtub case is an exception and was only made forbidden due to a decree that one may come to heat up also in a Keli Rishon. Hence according to them a very hot Keli Sheiyni would have the status of a Keli Sheiyni. [Machatzis Hashekel 318:35, based on Rashi 42a; Toras Shabbos 318:27; See P”M 318 M”Z 18]

[24] Final ruling in Admur 318:11 [regarding dispute on Rabbinical Michzi Kimivashel] “One should be stringent like the first opinion” and Admur 318:12 [regarding Kalei Habishul] “One should be stringent regarding all [uncooked foods and thus avoid placing them in a Keli Sheiyni] with exception to spices which the Sages [Mishneh Shabbos 42a] explicitly permitted to be placed in a Keli Sheiyni , as well as water and oil and other liquids  as will be explained.”; Rama 318:5; M”A 318:18; M”B 318:42

The reason: This is both due to that we suspect that all foods are Kalei Habishul which can cook in a Klei Sheiyni, as well as that we suspect of the opinion who rules that placing uncooked food in a Keli Sheiyni looks like you are cooking and is thus Rabbinically forbidden. [Admur ibid and ibid]

[25] Siddur Admur ibid regarding both rock and sea salt “One may not be lenient regarding our salt that although it is previously cooked….there are opinions which hold that it is forbidden to even place it in a Keli Sheiyni that is Yad Soledes, and one who is stringent is to be blessed.”; 2nd opinion and final ruling in Admur 318:17 regarding non-precooked salt [i.e. rock salt] “[However] there are opinions which say that salt only requires a slight amount of cooking and is thus forbidden to be placed even in a Keli Sheiyni so long as it is Yad Soledes. One who is strict will be blessed.”; Rama 318:9; Rebbe Chiyah Shabbos 42a in Lishna Kama; Tosafus Shabbos 42a; Mordechai Remez 308; Hagahos Ashri

[26] Siddur and Admur ibid and ibid; Rama ibid; See previous footnotes regarding Keli Rishon

[27] Implication of all Poskim ibid, including Admur 318:17-18 and Siddur Admur that the stringency for which one is granted a blessing only applies to a Keli Sheiyni; Piskeiy Teshuvos 318:43-45

[28] See Admur 318:11; Michaber 318:4; Peri Megadim 447 A”A 9; For further details and comprehensive halachic analysis, please refer to our corresponding sefer, The Shabbos Kitchen, Chapter 6 Halachas 15-16!

[29] Piskeiy Teshuvos 318:45; This follows those opinions who rule that a Keli Shelishi has the same status as a Keli Sheiyni as we explained in our corresponding Sefer recorded in the previous footnote

[30] Piskeiy Teshuvos 318:43; 45 footnote 412

^[31] See Admur 451:28; Shach 107:7; Taz 92:30; Shabbos Kehalacha Vol. 1 p. 84-86; For further details and comprehensive halachic analysis, please refer to our corresponding sefer, The Shabbos Kitchen, Chapter 6 Halacha 20!

[32] M”B 318:45; Minchas Yitzchak 5:127; Shabbos Kehalacha ibid

[33] See Igros Moshe 4:74; Shabbos Kehalacha Vol. 1 p. 88-92; Piskeiy Teshuvos 318:45 footnote 412; For further details and comprehensive halachic analysis, please refer to our corresponding sefer, The Shabbos Kitchen, Chapter 6 Halachas 11!

[34] M”B 318:45; 65; 118; Ketzos Hashulchan 124 footnote 15 and 39; So rule regarding Issur Viheter: Aruch Hashulchan 94:32; Kaf Hachaim Y.D. 94:72; Hakashrus 10:91; Rav Farkash rules that in accordance to Admur one may be lenient in this, however the M”B rules clearly that one is to initially be stringent unless it is a time of need.

^[35] Shabbos Kehalacha Vol. 1 p. 92

[36] For further details and comprehensive halachic analysis, please refer to our corresponding sefer, The Shabbos Kitchen, Chapter 6 Halacha 9E and Halacha 25!

[37] Admur 253:24 “If one transgressed and returned a pot on Shabbos to an area which (according to all opinions–So rules also) is forbidden for one to return there”; Admur 253:25 “(If a Jew himself) heated a food of which there are opinions which permit this to be done even initially, such as to place a food that was completely cooked but has liquid which has completely cooled down, and [by placing it near the fire] it heated up there until it became Yad Soledes, then even though [transgressing such a prohibition] makes one liable to bring a Chatas offering (for the Jew) [if the Jew placed the food there], nevertheless, since there are opinions which allow this to be done even initially, [therefore based on the letter of the law] one may rely on their words after the fact (to not forbid the food).” [Parentheses are in the original. See Ketzos Hashulchan 124 footnote 3 which says that Admur was in doubt in this ruling]; M”B 318:2; 318:27; Biur Halacha 253 “Veim Hichziru Yisrael” based on M”A 253:14; See Ketzos Hashulchan 124 footnote 3 based on Admur 253 KU”A 9

[38] Admur 318:17 “If one transgressed and placed salt even in Keli Rishon, even if it is on the fire, in which case he transgressed a prohibition [according to all], nevertheless the food is permitted [to be eaten on Shabbos] as the salt is nullified against the food. ”; Rama 318:9

[39] Admur ibid “There are opinions who argue and prohibit the food until after Shabbos.”; [Seemingly this refers to both the opinion of the Taz and M”A brought next which both write different limitations to the above ruling of the Rama. Admur does not specify anything of the ruling of the M”A here and hence seems to imply he holds that according to the Rama the salt is nullified in all cases.] Some Poskim rule the food is forbidden even if one placed a small amount of salt in the food. [Taz 318:15] Others rule it is forbidden only if one had not placed salt in the food before Shabbos, or if one placed so much salt that it alone is able to salt the food without the help of yesterday’s salt. [M”A 318:31; M”B 318:73]

[40] The reason: As the entire allowance of the Rama is because of the rule of Zeh Vizeh Gorem, and we do not say the rule of Zeh Vizeh Gorem when the two items are not working simultaneously. [Taz ibid] Alternatively, we only say the rule of Zeh Vizeh Gorem when there was a limited amount of salt added. [M”A and M”B ibid]