Bishul

From Halachipedia
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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. The halacha is that one may only recook an item that was fully cooked.[5]
  2. Even though for food that was fully cooked there is no violation of bishul when recooking it (even though there can be an issue of Hachzara), for liquids there is a violation of bishul when recooking it.[6]

Definition of Liquids

  1. Sephardim hold that as long as majority of the volume of the food is solid and a minority is liquid it is classified as a solid. If the majority is a liquid it is classified as a liquid.[7]
  2. Ashkenazim are more strict. Some poskim hold that any accumulation of liquid is considered liquid. A moist food with a drop of liquid on it is still considered solid.[8] However, other poskim define a solid by a food that is edible even when cold. A liquid is something that is only edible when heated up.[9]
  3. For example, there is a dispute whether ketchup is considered a solid or liquid since it pours (first opinion), on the other hand it is edible cold and so it is considered a solid (second opinion).[10]
  4. Soupy cholent is considered a liquid and dry cholent is considered a solid.[11]

Examples of Bishul with non-foods

  1. It's forbidden to melt off wax droplets using fire or hot water.[12]
  2. It's forbidden to heat a metal until it's red hot.[13] See also Electricity on Shabbat.
  3. It's forbidden to bake bricks or earthenware in a kiln.[14]

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).[15]
  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.[16] (See further for practically how one can reheat food on Shabbat).
  4. Another Biblical prohibition is hastening the cooking process.[17] 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.[18]

Hastening the cooking process

  1. It is forbidden to accelerate the cooking of a food which is on the fire.[19]
  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.[20] One may also not remove chulent from the pot on Friday night if the chulent isn’t fully cooked because doing so will hasten the cooking for the rest of the pot.[21]
  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.[22]
  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.[23]
  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.[24]
  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.[25]
  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.[26]

Cooking on a stove

  1. It’s forbidden to place anything on an electric stove unless the heat source is covered.[27]
  2. Before Shabbat, its permissible to leave cooked food on a covered electric stove which is set on a timer to begin operating on Shabbat.[28] In such a case, one may not place food on the covered stove on Shabbat even before it began operating.[29]
  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).[30]

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.[31]
  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.[32]
  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.[33] Sephardim consider it a Kli Sheni for the liquids that pour out of it to be considered iruy kli sheni that doesn't cook.[34]
  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.[35]
  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.[36]

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).[37]
  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.[38]
  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.[39]

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.[40]
    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.[41]
    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.[42]
  2. According to Ashkenazim, it is forbidden to put a cooked or boiled food such as chicken on top of a blech.[43]

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 [44] except for ox meat (because it requires intense heat to be cooked and it won’t cook in a Kli Rishon off the fire).[45]
  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.[46]
  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).[47]
  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.[48]

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.[49]
  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.[50]
  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. [51]

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.[52]
  2. It’s forbidden to pour from a Kli Rishon onto cold liquid or non-fully cooked solids.[53]
  3. According to Sephardim, it’s forbidden to pour water from a boiling pot to another pot that’s on the fire.[54] However, according to Ashkenazim it’s permissible.[55]
    1. If one found one’s chulent 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 chulent into a Kli Sheni and then poured in the boiling water.[56] See #Saving_a_Burning_Cholent for details and solutions.
  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.[57]
  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.[58]

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).[59]
  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.[60]
    1. Therefore, it’s permissible to pour from an urn onto tea essence which is still warm.[61]

Cooking in a Kli Sheni

  1. A Kli Sheni is a vessel into which a hot liquid or solid was poured.[62]
  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.[63]
  3. It’s forbidden to put any non-cooked food into a Kli Sheni which has the temperature of 113 degrees or greater [64] except a few items including water, olive oil, ginger, cinnamon, ox-meat, [65] and milk.[66]
  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.[67] For example, one shouldn’t put butter or seasoning on a hot (113 degree) potato or piece of meat.[68] An exception to the rule, is that salt and some say even ketchup may be placed on the hot foods.[69]

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.[70]
  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.[71]
  3. It’s forbidden to place tea leaves or ordinary cocoa in a Kli Sheni.[72]
  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.[73]

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.[74]

Pouring from a Kli Sheni

  1. One may pour from a Kli Sheni onto fully cooked liquid (whether it is warm or cold) [75]
  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.[76]

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.[77]

Cooking in a Kli Shelishi

  1. Some poskim permit making tea in a Kli Shelishi, while others forbid it. According to those who forbid, one should make tea essence before Shabbat and pour it into hot water of a Kli Sheni on Shabbat.[78]
    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.[79]
  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.[80]

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.[81]
  2. There's no prohibition of stirring a clear liquid such as chicken soup.[82]
  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).[83]

Fully cooked food

  1. Mixing fully cooked food which is on the fire is forbidden.[84]
  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.[85] 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.[86]

Food not on the fire

  1. If the fully cooked food is off the fire, one can completely mix the food.[87] However, some are strict unless there's a need.[88]
  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.[89]

Putting the Ladle Back in the Soup or Chullent

  1. It is permitted to use a ladle to serve soup even though placing the ladle back in the pot with droplets on it is going to cook those drops.[90]

Saving a Burning Cholent

  1. If one noticed a cholent that is burning or dried up on Shabbat morning, there are a several solutions:
    1. According to Ashkenazim, one could bring the cholent pot under the spigot of the urn or bring the urn to the cholent pot and pour hot water directly into the cholent. One should be careful to pour in the water slowly so that it doesn't stir its contents. Also, for reasons of kashrut one should make sure that the steam isn't so close to the spigot of the urn.[91] If one is taking the cholent pot to the urn one should make sure that the cholent pot can be returned to a covered fire, such as a blech or a crock pot that is lined with tin foil and the insert is raised up with tin foil or marbles.[92]
    2. According to Ashkenazim, if necessary, it is permitted to take a cup, fill it from the hot water urn and immediately pour it into the cholent put. It isn't considered cooking since the water was already boiling and it isn't an issue of hachzara since it was in one's hand with the intention to be put into another food on the fire. One should be careful to pour in the water slowly so that it doesn't stir its contents.[93]
    3. According to Sephardim all of the above options are forbidden.[94] Instead they should use the following methods:
    4. An alternative is to leave a bag of water in the cholent pot from before Shabbat and if one notices that the cholent is burning one can pop that bag on Shabbat.[95]
    5. Another option is not to add any water but just move it to a heating source that is cooler. For example, one could pick up the cholent from the cholent pot and then put it on a hot plate or on top of an inverted pan on top of a hot plate.[96]
    6. Some say that an alternative is to leave a metal ladle in the hot water urn for a while until it becomes very hot, specifically Yad Soledet Bo. Then one can ladle out some water from the urn and place it gently into the cholent pot.[97]
  2. Certainly one may not put in tap water or even cooked water that cooled down in a cholent that is burning.[98]

Hot Tap Water

  1. Turning on the hot tap water is prohibited on Shabbat.[99] It’s forbidden to use the hot water even if one turns off the hot water heater before Shabbat.[100]
  2. In cases of extreme need there may be a basis for permitting using hot tap water in a multi-family home, however, a Rav must be consulted before using this leniency.[101]
  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.[102] Some say that it is forbidden to turn off in all circumstances.[103]
  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.[104]
  5. See also a related topic, Showering on Shabbat.

Making Tea on Shabbat

  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.[105]
  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).[106]
  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).[107] Some question this practice when the tea essence is prepared before Shabbat in a kli sheni which is what is commonly done.[108] When making tea essence the bags should be removed before Shabbat to avoid the issue of Borer. If one didn't one can pour off tea essence as long as the liquid in the tea covers the bags of tea.[109]
  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.[110]

Lemon in Tea

  1. According to many poskim, one should not place a sliced lemon in a cup of tea because of the issue of cooking on Shabbat.[111] According to others, one may pour from a kli sheni onto lemon juice.[112]

Drying out the Cup

  1. It is permitted to pour hot water from a kli rishon onto cold droplets in a cup that is still wet. One should first shake it off to remove as much moisture as possible. Someone who is careful to dry it first will be blessed.[113]

Adding Sugar

  1. Since sugar is already cooked one could even put the sugar in the cup before pouring hot water from the urn on top of it (Iruy Kli Rishon) and certainly add it to a cup of hot tea that was already poured (Kli Sheni).[114]

Making Coffee on Shabbat

  1. It is permitted to make instant coffee and then to add milk and sugar to a Kli Sheni since it was cooked in its production.[115] It is a stringency to make instant coffee in a Kli Shelishi.[116]
  2. Making Starbucks VIA coffee is permitted specifically in a kli shelishi and not a kli rishon or kli sheni since it includes roasted kernels that aren't pre-cooked.[117]
  3. It is forbidden to use a French press on Shabbat. However, it is permitted to use a coffee filter on Shabbat, by placing the coffee grinds on the filter, and pouring the water through them. This is only true of the issue of Borer, however, it is forbidden to cook on Shabbat and so it would only be permitted to use a coffee if the water being used is a Kli Shelishi (according to those who allow using a Kli Shelishi).[118]
  4. On Yom Tov it is permitted to use a French press or a coffee filter to make coffee.[119]

Benefiting from Food Cooked on Shabbat

  1. If a person intentionally cooked on Shabbat the food is forbidden to benefit from forever for that person and for whoever he cooked for. For everyone else it is forbidden until the end of Shabbat.[120] Some poskim hold that it is only forbidden forever for the one who cooked but not for those he cooked for.[121]
  2. If a person unintentionally cooked on Shabbat the food is forbidden to benefit from for that Shabbat for everyone but after Shabbat it is permitted for everyone.[122] In extenuating circumstances, such as if there's not going to be other hot food for Shabbat, Ashkenazim can rely on the opinions that permit the food altogether on Shabbat when cooked unintentionally.[123]
  3. If water was added to a pot of food that was cooking on Shabbat even though it was a violation of Shabbat the food is permitted as long as the original food was more than the water added. Also, if the food would have burnt without the water it is forbidden even after the fact.[124]

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.
  2. *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.
  3. 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.
  4. 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.
  5. *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 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 holds 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.
    • 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.
  6. The Rambam Shabbat 9:3, Rashba Shabbat 40b s.v. meyvee, and Ran Shabbat 19a s.v. tanu (as explained by Bet Yosef 318:4) holds that Ein Bishul Achar Bishul applies to solids and liquids, but the Rosh Shabbat 3:11 argues that it only applies to solids and reheating liquids would be Bishul. The Shulchan Aruch is strict for the Rosh. Even though the Rama theoretically holds like the Rashba in practice he is only lenient if the liquid was originally hot on Shabbat and didn't cool down completely.
    • The Chazon Ish OC 50:9 holds that for water there's no dispute and everyone agrees that there's a Biblical violation of Bishul to reheat it since after it was heated up and cooled down there's no lasting effect of the original cooking on the water. He applies the same logic to reheating metal multiple times in regards to Electricity on Shabbat.
  7. Yechava Daat 2:45, Yabia Omer OC 6:48:16, Minchat Cohen Shabbat 2:2, Kaf Hachaim 318:62, Pri Megadim E"A 253:32
  8. 39 Melachos (Rabbi Ribiat v. 2 p. 594) writes that any accumulation of liquid on a food is considered a liquid. His proof is Rav Moshe (Igrot Moshe 4:74:7) and Mishna Brurah 318:32 who imply that any liquid is considered a liquid. Nonetheless, he learns from the Mishna Brurah that moist food is still considered a solid. Additionally a drop of liquid on a food is considered a solid.
  9. Orchot Shabbat p. 14 as explained by Rav Mordechai Willig in The Laws of Cooking and Warming Food on Shabbat p. 27
  10. Rav Mordechai Willig in The Laws of Cooking and Warming Food on Shabbat p. 27 explains the dispute between Rav Moshe Feinstein (igrot Moshe 4:74:5) and Rav Shlomo Zalman and Rav Elyashiv (Orchot Shabbat p. 14) in this manner. Rav Moshe holds it is a liquid since it pours, while the other poskim assume it is a solid since it is edible cold. Rav Willig accepts the definition of the other poskim.
  11. 39 Melachos v. 2 p. 645
  12. 39 Melachos (vol 2 pg 553)
  13. 39 Melachos (vol 2 pg 553)
  14. 39 Melachos (vol 2 pg 553)
  15. *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.
  16. 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.
  17. Rambam 9:4. This is codified as halacha in Shulchan Aruch 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.
  18. Rambam 9:5, 39 Melachos (vol 2, pg 554)
  19. Rambam 9:4. This is codified as halacha in Shulchan Aruch 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.
  20. 39 Melachos (vol 2 pg 554), Shabbos Kitchen (p. 7)
  21. Shabbos Kitchen (p. 8)
  22. 39 Melachos (vol 2 pg 559), Shabbos Kitchen (p. 8). See, however, Minchat Yitzchak 3:137.
  23. S”A 257:4, Shabbos Kitchen (p. 9)
  24. Shemirat Shabbat KeHilchata 1:17
  25. 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.
  26. Shemirat Shabbat KeHilchata 1:29
  27. Shemirat Shabbat KeHilchata 1:24
  28. Shemirat Shabbat KeHilchata 1:26
  29. Shemirat Shabbat KeHilchata 1:26
  30. Shemirat Shabbat KeHilchata 1:28
  31. Shemirat Shabbat KeHilchata 1:12, 39 Melachos (vol 2 pg 572)
  32. Shemirat Shabbat KeHilchata 1:2, 39 Melachos (vol 2 pg 572)
  33. Shemirat Shabbat KeHilchata 1:48
  34. Chazon Ovadia v. 4 p. 362
  35. Shemirat Shabbat KeHilchata 1:6
  36. Rabbi Mansour on Dailyhalacha.com
  37. 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)
  38. 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.
  39. Shemirat Shabbat KeHilchata. 1:8(1), 39 Melachos (vol 2 pg 563)
  40. S”A 318:4, Shemirat Shabbat KeHilchata 1:10, 15, Shabbos Kitchen (Rabbi Simcha Bunim Cohen; pg 43)
  41. 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.
  42. 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. Rav Hershel Schachter (The Laws of Cooking and Warming Food on Shabbat p. 179) writes that it is permitted to put challah in soup that was served with a ladle and adds no further conditions.
  43. 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.
  44. Shemirat Shabbat KeHilchata 1:14
  45. 39 Melachos (vol 2 pg 573-4)
  46. 39 Melachos (vol 2 pg 574)
  47. Shemirat Shabbat KeHilchata 1:50
  48. Shemirat Shabbat KeHilchata 1:52
  49. Shemirat Shabbat KeHilchata 1:16
  50. Shemirat Shabbat KeHilchata 1:16
  51. Shemirat Shabbat KeHilchata 1:16
  52. 39 Melachos (vol 2 pg 575)
  53. Shemirat Shabbat KeHilchata 1:46, 39 Melachos (vol 2 pg 575)
  54. Shulchan Aruch 253:4, Halichot olam vol 4 pg 61, Sh”t Yechave Daat 4:22, Or Letzion (vol 2), Rabbi Mansour on Dailyhalacha.com
  55. Mishna Brurah 253:85
  56. Yalkut Yosef (Shabbat vol 1 pg 107), Sh”t Yechave Daat 4:22
  57. Shemirat Shabbat KeHilchata 1:50, Rav Yitzchak Yosef (Motzei Shabbat Lech Lecha 5779 min 8)
  58. Shemirat Shabbat KeHilchata 1:46,9
  59. Shemirat Shabbat KeHilchata 1:51, 39 Melachos (vol 2 pg 576)
  60. Shemirat Shabbat KeHilchata 1:47
  61. Shemirat Shabbat KeHilchata 1:47
  62. 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.
  63. *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
  64. Shemirat Shabbat KeHilchata 1:53
  65. 39 Melachos (vol 2 pg 579-580)
  66. Mishna Brurah 318:39 at the end
  67. Shemirat Shabbat KeHilchata 1:58
  68. Shemirat Shabbat KeHilchata 1:58
  69. Shemirat Shabbat KeHilchata 1:58 because they are already cooked.
  70. Shaar HaTziyun 318:68, Shemirat Shabbat KeHilchata 1:59
  71. Shemirat Shabbat KeHilchata 1:49, 54. Rav Moshe Feinstein (Igros Moshe O.C. 4:74:16) writes it is permitted to put the instant coffee or sugar into a kli sheni it was already cooked and dried. He just adds that he himself was strict to only put instant coffee or sugar into a kli shelishi as a personal stringency.
  72. Shemirat Shabbat KeHilchata 1:53
  73. Shulchan Aruch O.C. 318:5 cites 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.
  74. Shemirat Shabbat KeHilchata. 1:8(2), 1:55, Mishna Brurah 318:39(end) regarding tea essence and milk
  75. Shemirat Shabbat KeHilchata. 1:8(2)
  76. Shemirat Shabbat KeHilchata 1:57
  77. 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.
  78. 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. Dor Hamelaktim v. 4 p. 2461 cites the Divrei Yatziv OC 155, Rav Yitzchak Berkowitz (Zera Shmutel fnt. 37), and Halacha Sheleimah 2:41 as lenient like Rav Moshe regarding tea. They also quote the Az Nidbaru 12:19, Shemirat Shabbat Kehilchata 1:63, Orchot Shabbat 1:43, Zachor Vshamor p. 119, Minchat Ish 5:87 as being strict on a kli shelishi for making tea. 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.
  79. Sh”t Shevet HaLevi 1:90
  80. Mishna Brurah 318:45, Shemirat Shabbat KeHilchata 1:59 (new edition 1:68). Shemirat Shabbat Kehilchata stipulates that the ladle must not have been left in the pot for a long time otherwise the ladle is a kli rishon.
  81. 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.
  82. 39 Melachos (vol 2 pg 560)
  83. 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.
  84. 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.
  85. 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.
  86. 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.
  87. 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.]
  88. 39 Melachos (vol 2 pg 561)
  89. Shemirat Shabbat KeHilchata 1:34
  90. Halacha Brurah (318:143 p. 361) writes that it is permitted to use a ladle to serve soup even though replacing the ladle back in the pot is going to cook to the liquid on it when put back in a kli rishon. Even though the drops might not be yad soledet bo and aren’t contained in a kli rishon, still they can be returned since it is a pesik reisha dlo nicha leh, the drops were cooked once and some rishonim hold ein bishul achar bishul even for liquids, and it is a chatzi shiur. he cites Mishna Halachot 6:67, Tzitz Eliezer 13:40, and Minchat Yitzchak 9:30 as also being lenient. He cites Menuchat Ahava 2:10:34 p. 353 who is strict regarding the wet cup but lenient regarding the wet ladle.
  91. Orchot Shabbat 1:2:73:1-2, 39 Melachos v. 2 p. 649
  92. Rabbi Willig in The Laws of Cooking and Warming Food on Shabbat pp. 124-6
  93. Orchot Shabbat 1:2:73:3, 39 Melachos v. 2 p. 649. 39 Melachos makes it clear that this option is less preferred than bringing the cholent pot directly under the urn. Rav Hershel Schachter (The Laws of Cooking and Warming Food on Shabbat p. 184) forbids this option altogether and only allows bringing the urn to the cholent pot.
  94. Shulchan Aruch O.C. 253:4, Rabbi Mansour citing Rav Ovadia Yosef in Halichot Olam v. 4 p. 61, Yachava Daat, and Rav Ben Tzion Abba Shaul in Or Letzion 2
  95. Rabbi Mansour, Or Hahalacha p. 175
  96. Or Hahalacha p. 175
  97. Or Hahalacha p. 175
  98. Orchot Shabbat 1:2:71
  99. Halachos of Shabbat (Rabbi Eider p. 395), The 39 Melachos (Rabbi Ribiat, vol 2 pg 639), Igrot Moshe YD 2:33, Yabia Omer OC 4:35. R' Eider cites Rav Henkin (Edut Lyisrael p. 122), Chelkat Yakov 1:78, Minchat Yitzchak 3:137, Tzitz Eliezer 2:18, Chazon Ish's letter in Menucha Nechona p. 61 who all agree that using the hot tap water is forbidden on Shabbat.
  100. The 39 Melachos (Rabbi Ribiat, vol 2 pg 640)
  101. The 39 Melachos (Rabbi Ribiat, vol 2 pg 640) considers it to be a case of safek pesik reisha with a grama which has a possibility of being lenient. However, he isn't sure that it is a grama. Yabia Omer 4:35 flatly rejects the idea that it is grama since as the hot water is remove new cold water enters. Igrot Moshe YD 2:33 agrees.
  102. The 39 Melachos (Rabbi Ribiat, vol 2 pg 640-1). Rav Shlomo Zalman Auerbach in Shulchan Shlomo 318:44 (cited by Halacha Brurah 318:74) writes that if the faucet is only a little bit open it is permitted to close it since the little bit of water that enters gets cooked immediately and closing the faucet doesn't cause the waters to cook any quicker.
  103. Halacha Brurah 318:74 writes that if the water boiler is electric and automatically continues to work even if the hot water has been running for a long time. Additionally, it is forbidden if the boiler works with a gas fire that turns off when the hot water is closed. However, if the system stops working once the water has emptied out then it is permitted to close the hot faucet once the water coming out is no longer Yad Soledet Bo since closing it isn't going to cause the water inside to get cooked as the system is currently off. In the footnote he discusses whether one can close the faucet because it is considered grama and he concludes that he isn't sure that it is grama based on Yabia Omer OC 4:35.
  104. The 39 Melachos (Rabbi Ribiat, vol 2 pg 640-1)
  105. Mishna Brurah 318:39, Aruch Hashulchan 318:28, 39 Melachos (Rabbi Ribiat, vol 2, pg 660).
    • However, Rabbi Chaim Jachter cites the opinion of Rav Yosef Dov Soloveitchik in the name of his grandfather, Rav Chaim Soloveitchik, who 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. Nefesh Harav pg. 170 quotes that Rav Yosef Dov Soloveitchik held this way himself as well. 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.
  106. Halacha Brurah 318:121 explains that one can even do iruy kli rishon initially onto instant tea which is cooked in advance and then dried and concentrated (e.g. Britannica ("Instant Tea")). Vaish Mordechai 1:8:4 explains that regarding sugar the Ben Ish Chai Bo n. 7 advises being strict for the Chayei Adam to place sugar in a kli sheni and not do iruy kli rishon upon them. Mishna Brurah 318:71 agrees. However, Yachava Daat 2:44 writes that it isn't necessary to be strict and iruy kli rishon upon sugar which was already cooked is totally fine.
  107. Mishna Brurah 318:39, Orchot Shabbat 1:74
  108. Orchot Shabbat 1:75 fnt. 165 writes that there’s no bishul achar bishul if something was cooked in a kli sheni before SHabbat to put it in a kli sheni again on Shabbat. Therefore, it is permitted to put the tea essence made in a kli sheni before Shabbat in a kli sheni on Shabbat since it is ein bishul achar bishul. Even though the tea essence is a cold liquid it isn’t considered a kalei habishul and as such it wouldn’t cook in a kli sheni. He acknowledges that the tea essence was never cooked in a kli rishon but it isn’t necessary since on Shabbat itself it is only going to be cooked in a kli sheni. However, he cites Rav Shmuel Auerbach who didn’t yet it. Additionally, Tehilah LDovid 318:19 holds that it is forbidden. The only type of ein bishul achar bishul that chazal permitted is when the food was cooked in a kli rishon before Shabbat. Piskei Teshuvot 318:33 cites this and others who agree.
  109. Orchot Shabbat 1:78
  110. 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 reiterates this point.]
    • 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.
  111. 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 on this issue. See Weekly Halacha by Rav Doniel Neustadt.
  112. Halacha yomit in the name of Chacham Ovadia Yosef
  113. Halacha Brurah (Bishul 318:141 p. 356) explains that it is permitted to pour hot water on top of droplets because it is a pesik reisha dlo nicha leh, iruy could be considered a kli sheni according to some rishonim, and the drops are a chatzi shiur. He cites Igrot Moshe OC 1:93, Or Letzion 2:30:10, Beer Moshe 6:110, Minchat Yitzchak 9:30-31 as being strict. Yabia Omer OC 4:33 is lenient. Halacha Brurah also cites Divrei Yatziv 1:156, Tzitz Eliezer 13:40, Tefila Lmoshe 1:36, Shevet Halevi 7:42:2, Mishna Halachot 6:67, Orchot Shabbat ch. 1 fnt. 156 citing Rav Shlomo Zalman Auerbach, and Meor Hashabbat v. 1 p. 161 citing Rav Elyashiv as lenient.
  114. Yalkut Yosef (Shabbat v. 3 Sechita Bshaar Dvarim n. 37) based on Panim Meirot 1:84 and Pri Megadim MZ 318:15 unlike the Zera Emet 1:39 who is concerned that the sugar wasn't cooked in the production.
  115. Shemirat Shabbat KeHilchata 1:49, 54. Rav Moshe Feinstein (Igros Moshe O.C. 4:74:16), Orchot Shabbat 1:83, 86
  116. Orchot Shabbat 1 fnt. 178 quotes the Shevet Halevi who is concerned that since the instant coffee was cooked and then baked it is like it was never cooked. He cites however, that Rav Shlomo Zalman Auerbach (Meor Hashabbat v. 3 n. 42:2) was lenient. He also cites from Meor Hashabbat that Rav Elyashiv was strict unless it would ruin the coffee being hot.
  117. Article by Rabbi Sultan on YUTorah. See Rabbi Aryeh Lebowitz's Ten Minute Halacha on this topic. He presents three basic opinions. Either it can be made in a kli sheni, kli shelishi, or shouldn't be made at all on Shabbat. Rabbi Yona Reiss's opinion is recorded on the CRC site.
  118. Article on Eretz Chemda's Site writes that it is permitted to use a coffee filter on Shabbat since it is similar to the case of a strainer used for wine in the Mishna Shabbat 137. However, it is forbidden to use a french press since that involves using a kli to separate a mixture.Rabbi Aryeh Lebowitz agreed that it is permitted to use the coffee filter based on Shulchan Aruch 319:9 but not a french press since that involves your action to separate the mixture.
  119. Rabbi Aryeh Lebowitz explains that since cooking and Borer are permitted on Yom Tov for the purpose of Ochel Nefesh as long as the food couldn't have been made in the same way before Yom Tov it is permitted to use a coffee filter or French press on Yom Tov to make coffee.
  120. Shulchan Aruch O.C. 318:1 in accordance with Rabbi Yehuda. Magen Avraham 318:2 adds that whoever he cooked for can't benefit like the cook himself. His proof is Y.D. 99:5. Mishna Brurah 318:5 agrees.
  121. Yalkut Yosef 318:1
  122. Shulchan Aruch O.C. 318:1
  123. Gra 318:1 follows Rabbi Meir. Mishna Brurah 318:7 is lenient for the Gra in a case of need. Yalkut Yosef 318:3 is strict even in difficult cases because Sephardim accepted Shulchan Aruch on this question.
  124. Halacha Brurah 318:5 is lenient for those who assume that bitul brov is sufficient to employ the leniency of the Shibolei Haleket. Minchat Shlomo 1:5 suggests it.