Bishul

From Halachipedia
Cooking.jpg

This article discusses the prohibition of cooking on Shabbat and its practical ramifications. A very closely related topic is Permissible ways to heat up food on Shabbat which includes halachot related to the covered fire (Blech), a pot on top of another pot, Kedierah Blech, Electric Hotplate, and more. Also, for the topic of cooking on Yom Tov, please see the Cooking on Yom Tov page.

General Guidelines of Bishul

  1. The prohibition of Bishul, cooking on Shabbat, is a general classification which includes heating up any substance, food or non-food, until a property of the substance changes. [1]
  2. The methods by which cooking can be violated include cooking, baking, roasting, broiling, frying, and microwaving. [2] Similarly, Bishul is violated by cooking with any heating element that reaches 113 degrees Fahrenheit including kerosene, gas or electric stove, hotplate, steamer, gas or electric oven. [3]

Cooking Without a Fire

  1. There is a machloket in the achronim if bishul by definition must be done with a fire. [4]

Ein Bishul Achar Bishul

  1. There is a rule that once something is cooked it cannot be halachically cooked any further. There is a debate among the Rishonim concerning the point at which a food is considered to be “cooked” in this sense. [5]

Examples of Bishul with non-foods

  1. It's forbidden to melt off wax droplets using fire or hot water. [6]
  2. It's forbidden to heat a metal until it's red hot. [7] See also Electricity on Shabbat.
  3. It's forbidden to bake bricks or earthenware in a kiln. [8]

Cooking food on Shabbat

  1. Because the most practical cases of Bishul apply to food, this is the category we will deal with extensively.
  2. Just in order to clarify, but not for practical ramifications, the Biblical prohibition is violated for solids, when one has cooked it for a third of the time usually needed to cook, and for liquids, when one heats it up to 110 degrees Fahrenheit. However, one can also violate the Biblical prohibition of Bishul by continuing to cook the food until it’s fully cooked. (For more details about the limitations of Biblical prohibition, see the footnote). [9]
  3. Practically speaking, it is forbidden to put any food on the fire or into a pot which is on the fire on Shabbat, whether the food is liquid or solid, cold or hot, cooked or raw. [10] (See further for practically how one can reheat food on Shabbat).
  4. Another Biblical prohibition is hastening the cooking process. [11] The practical ramifications of this will be discussed in the #Hastening the cooking process section below.
  5. If one notices that one put a food on the fire and it hasn’t completely cooked, one must remove it before it becomes fully cooked in order to avoid further violation of Shabbat. [12]

Hastening the cooking process

  1. It is forbidden to accelerate the cooking of a food which is on the fire. [13]
  2. For example, not fully cooked chulent may not be moved from one area on the blech to another area which is closer to the fire. [14] One may also not remove chullent from the pot on Friday night if the chullent isn’t fully cooked because doing so will hasten the cooking for the rest of the pot. [15]
  3. Similarly, if one turned on one's water urn right before Shabbat and the water isn't yet boiling, one may not take out water because in doing so one will hasten the cooking of the rest of the water remaining in the urn. [16]
  4. It is forbidden to cover a pot, even if it is on the blech, as long as the food isn’t fully cooked because covering it hastens the cooking process. Thus, one must beware not to open the cover of any pot on the blech, because one will not be permitted to return it to the pot. [17]
  5. Another important ramification of this halacha is stirring food on the fire. See the relevant halachot below.

Cooking in an oven

  1. It’s forbidden to return food to the oven even if it’s cooked and warm. [18]
  2. If there’s a possibility that the food isn’t fully cooked, if the oven door is opened or opened by itself, it’s forbidden to close the oven door, unless the food is removed. However, fully cooked food that was in the oven from before Shabbat may remain there when/if the oven door is opened. [19]
  3. It’s forbidden to use an oven which is thermostatically controlled since opening or closing the door will likely cause the flame to be increased. [20]

Cooking on a stove

  1. It’s forbidden to place anything on an electric stove unless it is covered. [21]
  2. Before Shabbat, it’s permissible to leave cooked food on a covered electric stove which is set on a timer to begin operating on Shabbat. [22] In such a case, one may not place food on the covered stove on Shabbat even before it began operating. [23]
  3. If the flame on the stove goes out and the gas is escaping, it’s permissible to turn off the tap. Preferably, this should be done with a variation (such as using the back of one’s hand, or one’s elbow). [24]

Cooking in a Kli Rishon

  1. It’s forbidden to put any food, liquid or solid, cooked or non-cooked, hot or cold, in a pot on the fire (Kli Rishon) even if one intends to remove it right away. [25]
  2. A Kli Rishon is a pot that was in contact with a fire or heat source. It continues to have the status of Kli Rishon if removed from the fire as long as it is 113 degrees. [26]
  3. A ladle can be considered a Kli Rishon if it was inserted in a hot Kli Rishon, and certainly if it was left in there for some time. [27]
  4. In general, no uncooked food, solid or liquid, may be placed in a Kli Rishon even if the food is hot and the Kli Rishon is off the fire. [28]
  5. One may not put down a hot pot on top of a wet counter top because doing so will heat up the water droplets. [29]

Fully cooked liquids

  1. According to Ashkenazim, it’s permitted to place a fully cooked liquid in a Kli Rishon that’s off the fire as long as the liquid is still warm (it hasn’t completely cooled since being heated). [30]
  2. According to Sephardim, it’s permissible to pour fully cooked hot liquid into a Kli Rishon only if the liquid is still 113 degrees. [31]
  3. Fully cooked liquid which has cooled (since it was heated originally while cooking) even if it became warm after it was cooked may not be reheated in a Kli Rishon and the contents of a Kli Rishon may not be poured into in. [32]

Fully cooked solids

  1. A fully cooked solid even if it’s cold may be placed in a Kli Rishon if the pot is not on the fire. [33]
    1. A fully baked (dry heat), roasted, or fried food may not be cooked(liquid heat). According to Ashkenazim one may not cook the baked, roasted or fried food in a Kli Rishon or Kli Sheni. [34]
    2. According to Ashkenazim, it’s forbidden to put any baked item such as croutons, soup nuts, challah, or matzah in hot soup that was poured directly from the pot. However it is permitted to place a baked food in soup that’s was poured into a bowl through a ladle that wasn’t left in the soup for any length of time. [35]
  2. According to Ashkenazim, it is forbidden to put a cooked or boiled food such as chicken on top of a blech. [36]

Non-fully cooked food or liquid

  1. It’s forbidden to put any non-fully cooked food, liquid or solid, in a Kli Rishon even if it’s off the fire [37] except for ox meat (because it requires intense heat to be cooked and it won’t cook in a Kli Rishon off the fire). [38]
  2. Course salt according to many authorities may be placed in a Kli Rishon which was removed from the fire because it doesn’t cook in a Kli Rishon, however, table salt can be placed in a Kli Rishon because it is cooked in the processing. # It’s forbidden to put any uncooked solids or liquids into a Kli Rishon on the fire. [39]
  3. It’s permissible to place a baby bottle of milk in a Kli Rishon which is off the fire and there’s a lot of milk in the bottle that it’s impossible that the milk will reach 113 degrees (if left in the Kli Rishon). [40]
  4. It’s permissible to pour a large amount of cold water into hot water in a Kli Rishon which is off the fire as long as the mixture thereby becomes less than 113 degrees and that the pouring is done in one swift action. [41]

Transferring food from one pot to another

  1. It’s permissible to transfer food from one pot on the fire to another pot that’s on a covered fire if the food in both pots are fully cooked. [42]
  2. If one’s fully cooked food is drying out one may pour boiling water from an urn into a pot that’s on the fire. If that’s not possible it’s permitted to take water with a ladle or spoon and pour it into the pot. [43]
  3. It’s permissible to separate fully cooked in one pot on the fire into two pots as long as the empty one was clean and dry and one complies with the rules of chazara. [44]

Pouring from a Kli Rishon

  1. Hot liquid poured from a Kli Rishon cooks to the same extent as a Kli Rishon on the outer layer of the substance it hits. [45]
  2. It’s forbidden to pour from a Kli Rishon onto cold liquid or non-fully cooked solids. [46]
  3. According to Sephardim, it’s forbidden to pour water from a boiling pot to another pot that’s on the fire. [47] However, according to Ashkenazim it’s permissible. [48]
    1. If one found one’s chullent burning in the morning, according to Sephardim it’s forbidden to pour boiling water into the Crock pot and would only be permissible if one first transferred the Chullent into a Kli Sheni and then poured in the boiling water. [49]
  4. It’s permissible to pour from a Kli Rishon onto a baby bottle filled with milk (even if it’s cold and uncooked) since the pouring only cooks the outer layer and in this case it’s the bottle (which doesn’t cook at this temperature), however, one should be careful that the bottle isn’t completely covered by the hot water. [50]
  5. It’s forbidden to pour hot water from a Kli Rishon onto regular sugar, saccharin, instant coffee, soup powder, instant cocoa, or uncooked tea leaves. [51]

Mixing hot and cold water

  1. It’s permissible to pour hot liquid from a Kli Rishon onto cold liquid if the remaining mixture will remain cool (less than 110 degrees). However it’s forbidden to pour a lot of hot liquid from a Kli Rishon onto a little cold liquid since the remaining mixture will be hot (greater than 110 degrees). [52]
  2. It’s permissible to pour from a Kli Rishon (even if it’s on the fire) onto fully cooked solids or fully cooked liquids which are still slightly warm, according to Ashkenazim. [53]
    1. Therefore, it’s permissible to pour from an urn onto tea essence which is still warm. [54]

Cooking in a Kli Sheni

  1. A Kli Sheni is a vessel into which a hot liquid or solid was poured. [55]
  2. There is disagreement amongst the poskim as to which types of food fall into the category of Kalei Bishul, foods for which it is forbidden to pour from kli sheni onto them. [56]
  3. It’s forbidden to put any non-cooked food into a Kli Sheni which has the temperature of 113 degrees or greater [57] except a few items including water, olive oil, ginger, cinnamon, ox-meat, [58] and milk. [59]
  4. Certain foods (such as potatoes, meat, kugel, or whole beans) store heat and should be treated as a Kli Rishon as long as it’s 113 degrees even if transferred to a Kli Sheni or Shelishi. [60] For example, one shouldn’t put butter or seasoning on a hot (113 degree) potato or piece of meat. [61] An exception to the rule, is that salt and some say even ketchup may be placed on the hot foods. [62]

Which foods may be placed in a Kli Sheni?

  1. Two exceptions to the rule of placing liquids in a Kli Sheni are oil and water which may be placed in a Kli Sheni. [63]
  2. It’s permitted to place sugar, saccharin, instant coffee, soup powder, milk powder, instant cocoa, table salt, or cooking salt into a Kli Sheni as they have been cooked in the manufacturing process. [64]
  3. It’s forbidden to place tea leaves or ordinary cocoa in a Kli Sheni. [65]
  4. A fully baked (dry heat), roasted, or fried food may not be cooked (liquid heat). According to Ashkenazim one may not cook the baked, roasted or fried food in a Kli Rishon or Kli Sheni. [66]

Fully cooked liquid

  1. Fully cooked liquid (whether it is warm or cold) may be placed in a Kli Sheni for example, tea essence, and there is what to rely on regarding pasteurized milk. [67]

Pouring from a Kli Sheni

  1. One may pour from a Kli Sheni onto fully cooked liquid (whether it is warm or cold) [68]
  2. One should not pour hot water (which has the temperature of 113 degrees) from a Kli Sheni onto a raw egg, non-boiled tea leaves, or herring. [69]

Mechzei Kimivashel

  1. One violates an Issur Derabanan if he or she places uncooked food into a Kli Sheini when it appears as if it is an act of cooking. However, one may place an item into a Kli Sheini for the sole purpose of enhancing the taste of its contents.[70]

Cooking in a Kli Shelishi

  1. Some forbid putting tea leaves in a Kli Shelishi, and some permit. According to those who forbid, one should make tea essence before Shabbat and pour it into hot water of a Kli Sheni on Shabbat. [71]
    1. Some say there’s an issue of putting tea leaves in a kli rishon on Shabbat even if they were put in boiling water before Shabbat. However, if the leaves were totally cooked there’s no issue of putting them in a kli rishon on Shabbat. [72]
  2. A fully baked (dry heat), roasted, or fried food may be cooked (liquid heat) in a Kli Shelishi. Therefore, if soup was ladled from a pot into a bowl it’s permissible to place bread in the bowl. [73]

Removing food from a pot on the fire

  1. For foods which have not yet been fully cooked, one may not remove a portion of the food since by reducing the amount of food in the pot, one hastens the cooking process. [74]
  2. Similarly, it’s forbidden to take water out of an urn in which the water has not reached its boiling point yet. [75]

Stirring hot food

Not fully cooked food

  1. It’s forbidden Deoritta Bishul) to stir hot food that isn’t fully cooked when it’s on the fire or removed from the fire as long as it’s 113 degrees in a Kli Rishon. [76]
  2. There's no prohibition of stirring a clear liquid such as chicken soup. [77]
  3. One can’t even take out a serving utensil from a Kli Rishon (even off the fire), unless the food is cold (not at the level of 113 degrees). [78]

Fully cooked food

  1. Mixing fully cooked food which is on the fire is forbidden. [79]
  2. Ashkenazim are strict and do not even take a serving spoon out of a pot of fully cooked food (that’s 113 degrees) while it’s on the fire. [80] However, Sephardim hold it’s permitted even if in the act one turns the food that was on top of the pot to be moved to the bottom closer to the fire. [81]

Food not on the fire

  1. If the fully cooked food is off the fire, one can completely mix the food. [82] However, some are strict unless there's a need. [83]
  2. It is permitted to put a spoon or ladle inside a pot, which is off the fire, as long as one is careful that the spoon or ladle is free from any remnants of water or uncooked food. [84]

Hot tap water

  1. Turning on the hot tap water is prohibited on Shabbat. [85] It’s forbidden to use the hot water even if one turns off the hot water heater before Shabbat. [86]
  2. In cases of extreme need there may be a basis for permitting using hot tap water, however, a Rav must be consulted before using this leniency. [87]
  3. One may leave on a hot water faucet from before Shabbat. One may not turn off a hot water tap if the tap has been running to the point that the water in the boiler is colder than Yad Soldet Bo (after 15-20 minutes), however if the faucet has only been running for a short time or it’s only open slightly and the water is still Yad Soldet Bo, then it’s permissible it turn it off. [88]
  4. Even when it’s permissible to turn on the hot water tap or if one left on the hot water tap from before Shabbat other issues including:
    1. make sure that one does not use the hot and cold water at the same time in one faucet and
    2. make sure one doesn’t pour directly onto moist or wet dishes rather one should fill a basin and then put in one’s wet dishes or preferably pour the hot water into a container and from there into a basin and then put inside it the wet dishes. [89]
  5. See also a related topic, Showering on Shabbat.

Making Tea on Shabbat

Tea.jpg
  1. According to many poskim tea leaves are considered foods which cook easily and could cook in a Kli Sheni and therefore it's forbidden to put a tea bag in a cup and pour upon it boiling water from the urn, nor may the tea bag be put in a cup in which water was poured from an urn. [90]
  2. The preferable way of making tea on Shabbat is to use instant tea which may be placed in a Kli Sheni (a cup with water which was poured from an urn) and better yet in a Kli Shelishi (a cup with water which was poured from a Kli Sheni). [91]
  3. Another preferable method is to prepare "tea essence" by cooking a tea bag before Shabbat, saving the flavored liquid, and putting it into a Kli Sheni (a cup with hot water which was poured from an urn). [92]
  4. Lastly, if one didn't prepare tea essence before Shabbat some poskim are lenient to make tea using a Kli Shelishi by pouring boiling water from an urn to a cup (Kli Sheni) and from that cup to another cup (Kli Shelishi) and putting the tea bag in the Kli Shelishi. [93]

Lemon in Tea

  1. According to many poskim, one should not place a sliced lemon in a cup of tea on Shabbat [94] According to others, one may pour from a kli sheni. [95]

Links

Sources

  1. The Mishna (Shabbat 73a) says baking bread is one of the 39 melachot. The Gemara (74b) includes cooking dyes as a violation of the melacha as well. This is codified as halacha by Rambam (Shabbat 9:1) and Tur 318:1. 39 Melachos (vol 2 pg 553) defines this prohibition precisely as heating up any substance, food or non-food, until a property of the substance changes.
    Rashi Shabbos 74b s.v. d’mirafei rafi writes that bishul occurs when the object is softened, while Rambam Shabbos 9:6 maintains that bishul can be done either by softening or hardening. Iglei Tal Bishul 9:6 infers from Rambam Shabbos 9:6 that the Av of bishul is only when the change to the object is permanent (such as baking a cake), but if the change will be undone (such as heating up metal that will eventually cool back down) then it is only a toldah of bishul.
    • Rambam (Shabbat 9:5) counts both roasting and frying as Bishul. Iglei Tal (Ofeh 1:1) explains that Rambam is counting ways to violate the Av in the first five Halachot of the chapter and from there and on he counts Toldot. However Lechem Mishna (Shabbat 8:12) says that since there’s no Nafka Minah between an Av and Toldah the Rambam wasn’t specific about differentiating them. Thus, Shemirat Shabbat KeHilchata 1:1 rules that cooking by either of these methods are forbidden deoraitta. For further clarification, Shabbos Kitchen (p. 1) includes baking, roasting, broiling, and frying.
    • Igrot Moshe 3:52 writes that cooking with a microwave is also a Biblical prohibition of Bishul. 39 Melachos (Rav Ribiat; pg 589) and Shabbos Kitchen (Rabbi Simcha Bunim Cohen; pg 2) agree.
  2. Shemirat Shabbat KeHilchata 1:1 and 1:4 writes that Bishul is violated with any heating element that reaches 113 degrees Fahrenheit including kerosene, gas or electric stove, hotplate, steamer, gas or electric oven. Shabbos Kitchen (p. 2) agrees. 39 Melachos (vol 2 pg 568) writes that cooking in a Kli Rishon, whether it is on or off the fire, where the food will reach 110 degrees is a violation of Bishul Deoritta.
  3. The Gemara Shabbos 39a records a machlokes about cooking in the sun (bishul b’chama). Rabbi Yose maintains that one is chayav for cooking in the sun (just like cooking on a fire), while the Chachamim are of the opinion that bishul b’chama is patur. Rashi Shabbos 39a s.v d’shari explains the opinion of the Chachamim as follows: bishul b’chama is patur because it is not the normal way to cook. R’ Moshe Feinstein Vol. 3, Responsa 52 extrapolates from this Rashi that had bishul b’chama been a normal way of cooking, it would be no different from cooking on a fire. In other words, bishul min hatorah can be accomplished even without an actual fire and this is why cooking in a microwave oven is considered bishul d’oraysa (since it is normal to cook in a microwave oven). However, R’ Shlomo Zalman Shemiras Shabbos 1 note 12 argues that Rashi meant that, by definition, cooking with anything other than a real fire (such as the sun or a microwave oven) is not bishul min hatorah.
  4. Rashba Shabbos 39a s.v. “kol sheba bichamin milifnei hashabbos shorin oso” maintains that once a food has been cooked to the level of ma’achal ben derusai (There is a further debate among the Rishonim regarding what exactly this degree of “cooked” is. Rashi (Shabbos 20a s.v. ben drusai) writes that it is a third cooked, while Rambam (Shabbos 9:5) holds that it is half cooked. Shulchan Aruch (254:2) paskens like Rambam, but Mishnah Brurah (253:38 and 43) writes that b’dieved we can rely on Rashi.) it cannot be cooked any further. However, Rambam Shabbos 9:3 argues that bishul no longer applies only when the food is completely cooked and further cooking will only worsen the quality of the food (mitztamek vera lo). Shulchan Aruch O”C 318:4 poskens like the Rambam, but the Biur Halacha S.v “afilu biodo roseach” writes that if the maachal ben drusai food was returned to a covered fire then b’dieved one can rely on the Rashba and eat it.
  5. 39 Melachos (vol 2 pg 553)
  6. 39 Melachos (vol 2 pg 553)
  7. 39 Melachos (vol 2 pg 553)
    • What does the Biblical prohibition of Bishul entail?
    • For non-foods, 39 Melachos (vol 2 pg 553) writes that the Biblical prohibition is only violated when a property of the substance is changed.
    • For solid food, 39 Melachos (vol 2 pg 553) writes that the Biblical prohibition is only violated when the food is changed from being inedible to edible. There is a dispute in the Rishonim about what is considered a minimal standard of edible for which it will be considered a violation of Bishul deoraitta. Rashi Shabbat 20a s.v. Ben Dursai holds that Bishul Deoritta is violated when it reaches half of it's cooking, while the Rambam Shabbat 9:5 holds that once it's reached a third of it's cooking one has violated Bishul Doeritta. Mishna Brurah 253:38 rules like the Rambam. Shemirat Shabbat KeHilchata 1:5 and Shabbos Kitchen (p. 3) agree. 39 Melachos (vol 2, pg 555) and Shabbos Kitchen (p. 3) explain that a third and a half refer to the time that the food would take to cook fully.
    • Even if a food is already minimally edible, there is a further violation of Bishul when furthering the cooking. S”A 318:4 rules that cooking a food, which is already edible, by any amount which makes it more cooked is a violation of Bishul, unless the food is fully cooked. Beiur Halacha s.v. Afliu, Shemirat Shabbat KeHilchata 1:5, Shabbos Kitchen (p. 3) agree.
    • Regarding liquids, S”A 318:14 rules that the Biblical violation of Bishul is violated when the liquid is heated up to Yad Soledet Bo. Shemirat Shabbat KeHilchata 1:5 defines Yad Soledet Bo, in matters in which one has to be strict to avoid any violation, as 113 degrees Fahrenheit. Igrot Moshe 4:74:3, however, rules that one should be strict to consider Yad Soledet Bo as 110 degrees. Shabbos Kitchen (p. 5) and 39 Melachos (vol 2 pg 558) agree. Chazon Ovadia Shabbat Part 4: page 371 rules that yad soledet bo is only 104 degrees Farenheit
    • Even if a liquid is Yad Soledet Bo, most poskim hold that there is a Biblical violation of Bishul if one continues to heat it until it reaches its boiling point. Sh"t Igrot Moshe 4:74(3) writes that it's sufficient to assume that once a liquid is 160 degrees heating it further it's permissible to heat it further. However, Otzrot Shabbat in name of Rav Elayshiv, Sh"t Shevet HaLevi 7:42(3), and Minchat Yitzchak 10:28 hold it must reach it's boiling point before being allowed to heat it further. Shabbos Kitchen (p. 3) writes that most poskim consider this to be a Torah prohibition.
    • What is defined as a liquid? Shabbos Kitchen (p. 11) writes that only something which is completely solid such as meat, chicken, or kugel is considered solid. Igrot Moshe 4:74:7 writes that one should not rely on the Minchat Kohen and the Pri Megadim’s opinion isn’t clear.
  8. Shemirat Shabbat KeHilchata 1:12 rules that it is forbidden to put any food on the fire or into a pot which is on the fire on Shabbat, whether the food is liquid or solid, cold or hot, cooked or raw.
    • This ruling is partially based on a Rabbinic prohibition to place a solid food in an area where it could become cooked or place a liquid where it could become Yad Soledet Bo. This Rabbinic prohibition is codified in S”A 318:14 and 17.
  9. Rambam 9:4. This is codified as halacha in S"A 254:4 in regards to the halacha of stirring food on the fire. Rabbi Akiva Eiger 318:1, 39 Melachos (vol 2 pg 559), and Shabbos Kitchen (p. 7) also quote this as the halacha.
  10. Rambam 9:5, 39 Melachos (vol 2, pg 554)
  11. Rambam 9:4. This is codified as halacha in S"A 254:4 in regards to the halacha of stirring food on the fire. Rabbi Akiva Eiger 318:1, 39 Melachos (vol 2 pg 559), and Shabbos Kitchen (p. 7) also quote this as the halacha.
  12. 39 Melachos (vol 2 pg 554), Shabbos Kitchen (p. 7)
  13. Shabbos Kitchen (p. 8)
  14. 39 Melachos (vol 2 pg 559), Shabbos Kitchen (p. 8). See, however, Minchat Yitzchak 3:137.
  15. S”A 257:4, Shabbos Kitchen (p. 9)
  16. Shemirat Shabbat KeHilchata 1:17
  17. Shemirat Shabbat KeHilchata 1:17. Shabbos Kitchen (p. 9) explains that it is forbidden to close the oven door with not fully cooked food inside because it hastens the cooking process. See also Rama 259:7.
  18. Shemirat Shabbat KeHilchata 1:29
  19. Shemirat Shabbat KeHilchata 1:24
  20. Shemirat Shabbat KeHilchata 1:26
  21. Shemirat Shabbat KeHilchata 1:26
  22. Shemirat Shabbat KeHilchata 1:28
  23. Shemirat Shabbat KeHilchata 1:12, 39 Melachos (vol 2 pg 572)
  24. Shemirat Shabbat KeHilchata 1:2, 39 Melachos (vol 2 pg 572)
  25. Shemirat Shabbat KeHilchata 1:48
  26. Shemirat Shabbat KeHilchata 1:6
  27. Rabbi Mansour on Dailyhalacha.com
  28. Mishna Brurah 318:24 bringing the Rama 318:15 even in the case of a Kli Rishon, Shemirat Shabbat KeHilchata. 1:7,15, Shabbos Kitchen (pg 41-3)
  29. S”A 318:4 writes that if the liquid has cooled it may not be poured into a kli rishon. Mishna Brurah 318:24 explains that it must be Yad Soldet Bo according to S”A in order to pour it into a kli rishon.
  30. Shemirat Shabbat KeHilchata. 1:8(1), 39 Melachos (vol 2 pg 563)
  31. S”A 318:4, Shemirat Shabbat KeHilchata 1:10, 15, Shabbos Kitchen (Rabbi Simcha Bunim Cohen; pg 43)
  32. S”A 318:5 brings two opinions and Rama writes that the Minhag is to be strict even in a Kli Sheni. Shemirat Shabbat KeHilchata 1:59 holds like the Rama that it’s forbidden even in a Kli Sheni.
  33. Shemirat Shabbat KeHilchata 1:59 holds like the Rama that it’s forbidden even in a Kli Sheni, however he considers the soup in the bowl a Kli Shishi if the soup was taken through a ladle that wasn’t left in the soup for any length of time. This is also codified in Hilchot Shabbat pg 263 by Rabbi Shimon Eider and Shabbos Kitchen pg 38 by Rabbi Simcha Bunim Cohen.
  34. Mishna Brurah 318:41 and Shemirat Shabbat KeHilchata 1:60 writes that since the chicken or cooked food was cooked originally with wet-heat and now it’s being cooked through dry heat like roasting it’s forbidden to heat up the food.
  35. Shemirat Shabbat KeHilchata 1:14
  36. 39 Melachos (vol 2 pg 573-4)
  37. 39 Melachos (vol 2 pg 574)
  38. Shemirat Shabbat KeHilchata 1:50
  39. Shemirat Shabbat KeHilchata 1:52
  40. Shemirat Shabbat KeHilchata 1:16
  41. Shemirat Shabbat KeHilchata 1:16
  42. Shemirat Shabbat KeHilchata 1:16
  43. 39 Melachos (vol 2 pg 575)
  44. Shemirat Shabbat KeHilchata 1:46, 39 Melachos (vol 2 pg 575)
  45. S”A 253:4, Halichot olam vol 4 pg 61, Sh”t Yechave Daat 4:22, Or Letzion (vol 2), Rabbi Mansour on Dailyhalacha.com
  46. Mishna Brurah 253:85
  47. Yalkut Yosef (Shabbat vol 1 pg 107), Sh”t Yechave Daat 4:22
  48. Shemirat Shabbat KeHilchata 1:50
  49. Shemirat Shabbat KeHilchata 1:46,9
  50. Shemirat Shabbat KeHilchata 1:51, 39 Melachos (vol 2 pg 576)
  51. Shemirat Shabbat KeHilchata 1:47
  52. Shemirat Shabbat KeHilchata 1:47
  53. 39 Melachos (vol 2 pg 577). The Mishna on Shabbos 42a states that while one may not place spices into a Kli Rishon, there is no prohibition of doing so into a Kli Sheini. The Gemarah on Shabbos 40b relates that when the Amora Rav Avdimai wished to heat up his flask of oil, he was advised to place it into a Kli Sheini in order to avoid the problem of Bishul. The Gemara explains that this heter is based on the assumption that a Kli Sheini does not have the ability to fully cook an item placed inside of it. There is a discussion among the Rishonim as to the exact reason for this heter.
    • Tosfos on 40b writes that since a Kli Rishon was originally placed directly on top of the fire, its wall will remain heated for an extended period of time. However, since a Kli Sheini was never positioned on top of the flame, its wall will not retain this same level of heat and will cool off at a much quicker pace. According to this logic, the heter of a Kli Sheini would apply even if the contents inside the Kli are still at a level of yad soledes bo because the walls of the vessel are already in the process of cooling down.
    • The Mishna on Shabbos 145b explains that, although it is forbidden to place uncooked foods into a Kli Rishon on Shabbos, one would be permitted to pour hot water onto these foods from a Kli Sheini. Rashi explains that this act of pouring is not considered Bishul and would therefore be permissible even if done on Shabbos itself. * However, the Mishna goes on to explain that there are certain types of fish for which even pouring would be considered a legitimate act of Bishul as they are more “easily cooked” and therefore considered to be within the category of Kalei Bishul. Since the Mishna writes that even pouring from a Kli Sheini would be assur, we can derive that placing these types of foods directly into a Kli Shinei would be forbidden as well. * There is a disagreement amongst the poskim as to which types of foods fall into this category of Kalei Bishul. The Mishna Brurah (Be’ur Halacha Siman 318 S”K 4) writes that any food which the Gemarah does not explicitly leave out of the category of Kalei Bishul would be forbidden to be placed into a Kli Sheini. However, the Chazon Ish (Siman 52 S”K 19) limits the category of Kalei Bishul. He explains that the only additional items which would be considered Kalei Bishul are those which appear to be easily cooked
  54. Shemirat Shabbat KeHilchata 1:53
  55. 39 Melachos (vol 2 pg 579-580)
  56. Mishna Brurah 318:39 at the end
  57. Shemirat Shabbat KeHilchata 1:58
  58. Shemirat Shabbat KeHilchata 1:58
  59. Shemirat Shabbat KeHilchata 1:58 because they are already cooked.
  60. Shemirat Shabbat KeHilchata 1:53
  61. Shemirat Shabbat KeHilchata 1:49, 54. Rav Moshe Feinstein (Igros Moshe O.C. 4:7) writes that some are stringent to first place the coffee into a kli sheini before adding the coffee as to avoid the potential problems of Kalei Bishul
  62. Shemirat Shabbat KeHilchata 1:53
  63. S”A 318:5 brings two opinions and Rama writes that the Minhag is to be strict even in a Kli Sheni. Shemirat Shabbat KeHilchata 1:59 holds like the Rama that it’s forbidden even in a Kli Sheni.
  64. Shemirat Shabbat KeHilchata. 1:8(2), 1:55, Mishna Brurah 318:39(end) regarding tea essence and milk
  65. Shemirat Shabbat KeHilchata. 1:8(2)
  66. Shemirat Shabbat KeHilchata 1:57
  67. The Mishnah writes on 42a that one is allowed to place spices into a Kli Sheini even though it appears as if the spices are cooking. The Mishnah Brurah 318:34 explains that since the spices are clearly being used to enhance the taste of the food, there is no issue of Mechzei Kemevashel.
    Although the Shulchan Aruch and Rama leave out the rule of Mechzei Kemevashel, the Mishna Brurah (Smian 318 S”K 34) quotes it as the accepted halacha.
  68. Chazon Ish 52:19, Aruch HaShulchan 318:28, Shabbos Kitchen (Rabbi Simcha Bunim Kohen; pg 32) hold that tea leaves are food that are easily cooked and a Kli Shelishi is no different than a Kli Sheni. However, Igrot Moshe 4:74 bishul #15 permits putting tea leaves in a Kli Shelishi since he holds that a Kli Shelishi can’t cook at all. The Mishnah Brurah 318:47 quotes that there would be no issue of placing food into a Kli Shlishi even if it is considered to be easily cooked. According to those who forbid, Mishna Brurah 319:39 writes that one should make tea essence before Shabbat and then pour it into hot water of a Kli Sheni on Shabbat. See Sh”t Shevet Halevi 1:90 who argues on the advise of the Mishna Brurah to cook the leaves before Shabbat and then again on Shabbat because Sh”t Maharam Shik 132 suggest that there may be bishul acher bishul with the tea leaves.
  69. Sh”t Shevet HaLevi 1:90
  70. Shemirat Shabbat KeHilchata 1:59
  71. Shabbos Kitchen (Rabbi Simcha Bunim Cohen; pg 8)
  72. Shabbos Kitchen (Rabbi Simcha Bunim Cohen; pg 8), Shemirat Shabbat KeHilchata (1:35 note 96)
  73. In Shabbat 18b, the Gemara says that there’s no issue of Megis (stirring) a hot food if the pot is totally sealed with cement implying that stirring a hot food is forbidden as Bishul, cooking (Rashi 18b s.v. Rambam 3:11, S”A 318:18, Shemirat Shabbat KeHilchata 1:31, and 39 Melachos (vol 2 pg 560) codify this law as halacha.
  74. 39 Melachos (vol 2 pg 560)
  75. When Rambam 3:11 and S”A 318:18 quote the law of stirring, they extend it to the case of removing a serving spoon from a hot food which causes a mixing of the food. Bet Yosef explains that when the Rambam forbids by a pot on the fire, it also includes the case of where the pot came off the fire and is still boiling. This is found explicitly in the Ran 6b and Rabbenu Yerucham 3:12 pg 68a. S”A rules this law with the language of a pot removed from the fire. This is brought as halacha in Shemirat Shabbat KeHilchata 1:31.
  76. Ritva Shabbat 18b (quoted in Tal Orot pg 39) writes that even after the food was cooked it’s still forbidden on a rabbinic level to stir the hot food. S”A 318:18 rules one can’t remove a spoon from a food that’s not fully cooked but if it’s fully cooked it’s permitted, which seemingly means that one can remove a spoon from a fully cooked food but not to actually mix it. Similarly, Bet Yosef 321 quotes Sh”t Rambam 68 (and the halacha is also found in Shabbat 21:13) who permits mixing a hot food that was fully cooked and removed from the fire. Bet Yosef adds that even though it’s forbidden even off the fire as long as it’s hot here it’s permitted because it’s totally cooked. Rav Ovadyah (Yalkut Yosef Shabbat vol 3 pg 187; Kol Sinai Tevet 5723) implies from these sources that actually mixing a totally cooked food while on the fire is forbidden as Mechzei KeMevashel (appears like cooking). Or Letzion 2 pg 238 writes that the Kol Bo (quoted by Bet Yosef 253) who forbids stirring a fully cooked pot on the fire is a Deoritta prohibition, while Mishna Brurah 318 argues that clearly stirring a fully cooked food is only forbidden on a rabbinic level (as is explicit in the Ritva). However, Ramach (quoted by Kesef Mishna 9:4), Mamer Mordechai 318:20, and Chazon Ish 37:15 permit actual mixing even though the pot is on the fire because the food is completely cooked.
  77. Ran 6b (according to the version of the Bet Yosef 318:18 quoted by the Hagahot HaBach on the Rif) writes that even removing a serving spoon from the pot of hot food is forbidden because in that act one stirs the food. Rambam 3:11 also rules that putting a serving spoon is forbidden because of stirring. However, Magid Mishna 3:11 explains that that Rambam (and Ran who says this explicitly) only forbade a hot food that wasn’t totally cooked but stirring is permitted if it’s totally cooked (Bet Yosef adds that according to those who hold there’s no issue of cooking once it’s cooked to the stage of Machal Ben Derosai Dursai, here too, stirring is permitted at Machal Ben Dursai). [Interestingly, Maggid Mishna 9:4 says in name of Ramban (18b D”H VeHalo Megis) and Rashba (18b s.v. Tzemer LeYurah) that once the hot food was stirred once it’s considered cooked and there’s no issue of cooking with the second stirring.] S”A 318:18 rules that it’s permitted to remove a spoon from a fully cooked food even when it’s on the fire. However, the Rama is strict not to remove a utensil or stir the pot whether it’s on the fire or even off the fire based on Sh”t Mahari Vill 30. The achronim including Eliyah Raba 318:40, Chaye Adam 20:9, Levush 321:9, Pri Megadim M”Z 321:23, Sh”t Zera Emet 1:40, Tehila LeDavid 252:1, Mishna Brurah 318:117, 39 Melachos (vol 2 pg 561-2), and Shemirat Shabbat KeHilchata 1:32 agree that Ashkenazim should be strict like the Rama while the food is still on the fire both not to stir and not to remove a utensil (and they mention that if there’s one who wants to be stringent one should be stringent in regards to stirring something off the fire). Sh”t Igrot Moshe 4:74 is strict like the Rama regarding food that’s on the fire and explains that that one may not stir food on the fire because one might assume that the food is totally cooked and it may turn out that it isn’t, which would be a violation of a Torah prohibition. Shemirat Shabbat KeHilchata 1:32 adds that if there’s going to be no way to remove food from the pot and return it to the fire (because of absence of a suitable cover of the fire) one may be lenient and remove food (not stir) as long as the food is surely fully cooked.
  78. See above note. The Chida in name of the Radvaz 3:411, Taz 318:23, Sh"t Yabea Omer OC 10:55, and Yalkut Yosef (Shabbat vol 3 pg 187) rule like S”A. [Interestingly, Orchot Rabbenu Kehilat Yacov pg 149 writes that in the house of the Chazon Ish and Kehilat Yacov (who were Ashkenazic), they actually took food from a pot on the fire when the food was fully cooked, not like the Rama (however, Orchot Rabbenu explains that since they were so strict regarding Chazara, if they weren’t lenient in this regard, they wouldn’t have hot food on Shabbat). The Chazon Ish 37:15 actually rules this way.
  79. Bet Yosef 321 quotes Sh”t Rambam 68 (and the halacha is also found in Rambam Hilchot Shabbat 21:13) who permits mixing a hot food that was fully cooked and removed from the fire. S”A 318:18 rules that it’s permitted to remove a spoon from a fully cooked food even when it’s on the fire, implying when off the fire and it’s fully cooked one can actually stir the food. Yalkut Yosef (Kitzur S”A vol 1 pg 631), and Shemirat Shabbat KeHilchata 1:32 rule that once the food is off the fire, one may stir the food. [Mishna Brurah 318:117 writes that if one want to be strict one shouldn’t stir it but just remove the food from the pot.]
  80. 39 Melachos (vol 2 pg 561)
  81. Shemirat Shabbat KeHilchata 1:34
  82. The 39 Melachos (Rabbi Ribiat, vol 2 pg 639)
  83. The 39 Melachos (Rabbi Ribiat, vol 2 pg 640)
  84. The 39 Melachos (Rabbi Ribiat, vol 2 pg 640)
  85. The 39 Melachos (Rabbi Ribiat, vol 2 pg 640-1)
  86. The 39 Melachos (Rabbi Ribiat, vol 2 pg 640-1)
  87. Mishna Brurah 318:39, Aruch Hashulchan 318:28, 39 Melachos (Rabbi Ribiat, vol 2, pg 660).
    • However, Rabbi Chaim Jachter quotes Rabbi Yosef Adler quoting Rav Yosef Dov Soloveitchik who said that his grandfather, Rav Chaim Soloveitchik, made tea on Shabbat using a Kli Sheni, because the gemara Shabbat 42b says that it is permissible to put spices into a kli sheini, and Rav Chaim considered tea to be a spice. Rav Shlomo Zalman Auerbach (quoted in Shmirat Shabbat KeHilchata chapter 1 note 152) is quoted as saying that the spices referred to in the gemara in shabbat 42b were different then the spices of today, and that today's spices would be considered like kalei habishul.
  88. Igrot Moshe 4:74(16)
  89. Mishna Brurah 318:39
  90. Igrot Moshe 4:74(15) writes that a Kli Shelishi doesn't cook at all and so it's permissible to put a tea bag in a Kli Shelishi. This is also the opinion of the 39 Melachos (Rabbi Ribiat, vol 2, pg 661). There are some who disagreed with this idea, namely the Aruch HaShulchan 318:28 and Shemirat Shabbat KeHilchata 1:63 (in the new edition, see note 192). [The Mishna Brurah 318:39 clearly leave out this option implying that it's not a valid alternative. Rabbi Aryeh Lebowitz in an article on yutorah.org writes "The Mishna Brurah writes that one may not cook tea even in a Kli Shelishi." and in a Rabbi Lebowitz on the Ten Minute Halacha repeats the same statement which seemingly isn't totally precise as the Mishna Brurah actually makes no mention of Kli Shelishi at all.]
    • Sh”t Shevet HaLevi 1:90 writes that there’s an issue of putting tea leaves in a kli rishon on Shabbat even if they were put in boiling water before Shabbat. However, if the leaves were totally cooked there’s no issue of putting them in a kli rishon on Shabbat.
  91. Consensus of many poskim (Igros Moshe O.C. 4:74-18; Harav S.Z. Auerbach, quoted in Shemiras Shabbos K'hilchasah 1, note 150; Harav Y.S. Elyashiv, quoted in Me'or ha-Shabbos 1:221) unlike the Chazon Ish (O.C. 52:19) who tends to be lenient. see Weekly Halacha by Rav Doniel Neustadt
  92. Halacha yomit in the name of Chacham Ovadia Yosef