The Principles of the Melakhot / Why Melakha Is Forbidden on Yom Tov

On the holy days of Shabbat and Yom Tov, one may not do melakha, for at these times we transcend the limitations of this world, with all its sinfulness and cursedness, in which man must work hard to sustain and support himself. Originally, when God created man, He did not intend him to work and toil in order to support himself (Kiddushin 82b). Had Adam clung to God, the Source of all life, his sustenance would have been available to him toil-free. It was only after Adam sinned and ate from the Tree of Knowledge of Good and Evil that he was expelled from the Garden of Eden, brought curse upon the earth, and was sentenced to having to endure pain and toil to make a living. Thus we read: “Cursed be the ground because of you. By toil shall you eat of it all the days of your life; thorns and thistles shall it sprout for you. But your food shall be the grasses of the field. By the sweat of your brow shall you get bread to eat, until you return to the ground” (Bereishit 3:17-19). Through the hard work decreed upon people to sustain themselves, they gradually make restitution for the sin. On the other hand, on account of this hard work, people are susceptible to immersing themselves in the material world and forgetting their exalted soul. Therefore, God gave us holy days, when we can transcend the sin and the curse that necessitate our working for a living.

Nevertheless, there is a difference between Shabbat and Yom Tov. On Shabbat, all melakha is forbidden, as we read: “But the seventh day is a Shabbat of the Lord your God; you shall not do any melakha” (Shemot 20:10). In contrast, on Yom Tov, melakha involving food preparation for that day is permitted (as explained below).

On Shabbat we ascend to a very high level of faith. As a result of our realization that all is in the hands of God, we subordinate ourselves entirely to divine providence and cease all melakha. We are fully focused on absorbing the bounty that God provides for us. The soul engages in Torah and prayer, and the body engages in food and sleep. In contrast, Yom Tov is more this-worldly and gives expression to our role in repairing the world.

On Shabbat, even in the Garden of Eden man was meant to be elevated to the level of cessation of all work. Yom Tov, though, corresponds to the six weekdays in the Garden of Eden. God left room for human effort in order to include him in the project of repairing and sustaining the world. “The Lord God took the man and placed him in the Garden of Eden, to till it and tend it” (Bereishit 2:15). The difference between then and now is that in the Garden of Eden, the work would have been done in a relaxed, joyful way, and its positive result – improving the world – would have been immediately apparent. Corresponding to this, we may prepare food on Yom Tov, as this work is relatively pleasant and enjoyable.

Even though Shabbat, on which no melakha at all is done, is holier than Yom Tov, the simḥa of Yom Tov is greater, because its holiness is more accessible to us. Additionally, it is in the merit of the Jewish people that the festivals are sanctified. It is thus appropriate that melakha to prepare festive meals for the Jewish people is permitted.

Since Yom Tov is a weekday that the Jewish people transform into a holy day (see 1:3 above), its impact on weekdays is more direct. Cessation from melakha on Shabbat is not meant to guide the six days of the week. Rather, its intrinsic holiness uplifts them. In contrast, Yom Tov, which takes place on weekdays, is more closely connected to the world of action. On these days, we thank God for blessing what we produce, and in turn we focus our actions and consider our role in the world. This is why the Sages tell us that the days of Yom Tov are days of judgment (1:2 above); it is at these times that we earn blessing through our efforts.

The melakhot we may do on Yom Tov are meant to increase the joy we experience when performing a mitzva. Through them, we can perfect all the melakhot we do all week long. Materialistic man is confined and constricted by Adam’s sin; he must work hard to acquire luxury items, which he hopes will make him happy. But they do not make him happy, so he keeps wanting to acquire more and more possessions, becoming enslaved to his appetites and to hard work.

In contrast, one who experiences the simḥa of a festival, through Torah study and festive meals, does not need luxury items, because he is happy with what he has. He is not enslaved to his work, but he sees its constructive value, and he derives satisfaction and benefit from it.

The Principles of the Melakhot / Melakhot Permitted on Yom Tov

On Shabbat, one may not do any melakha, as the verse explicitly states: “But the seventh day is a Shabbat of the Lord your God; you shall not do any melakha” (Shemot 20:10). In contrast, on Yom Tov, one may do melakha involving same-day food preparation. “It shall be a sacred occasion for you. No melakha at all shall be done on them; only what every person is to eat, that alone may be prepared for you” (Shemot 12:16). Similarly, we read: “It shall be a sacred occasion for you; you shall not do any melakha of labor” (Vayikra 23:7). We see that it is only melakha of labor (melekhet avoda) that one may not do, while he may do melakha that he performs daily in his home, in preparing his food (Ramban ad loc.).

Therefore, on Yom Tov one may knead dough and bake bread and cake; he may cook meat, fish, fruit, vegetables, and all other food; animals and birds needed for the day’s meals may be slaughtered; when cooking and baking, the flame or temperature may be adjusted upward or downward as necessary; and food for a meal may be carried from one reshut to another.

However, one may not reap standing grain, harvest grapes, thresh sheaves, winnow grain to separate out rocks and chaff, mill flour, hunt animals, fowl, or fish, or press grapes into wine or olives into oil. All of these melakhot are deemed “melekhet avoda” and are forbidden on Yom Tov. The indication that a particular melakha is melekhet avoda is that it is generally done by hired workers, who prepare large quantities of produce to last a long time or for commercial purposes. In contrast, permitted melakhot are generally performed at home for that day’s needs.

It must be stressed that this rule – that one may not do melekhet avoda on Yom Tov – applies even if it is easy, and even if it is for immediate Yom Tov needs. For example, it is forbidden to pick even a few fruits from a tree in one’s garden for a Yom Tov meal. Similarly, it is forbidden to catch fish from a private pond, even for that day’s meal. Nevertheless, the Rishonim disagree as to the severity of the prohibition. Some say that if these melakhot are performed for Yom Tov needs, they are not prohibited by Torah law. Rather, the Sages prohibited them because they are likely to drag out, to the point that one may end up spending the entire day working, rendering his Yom Tov indistinguishable from a weekday; he will enjoy neither Torah study nor festive meals. Additionally, since these melakhot usually are performed for long-term needs, it is possible that if they would be permitted for immediate Yom Tov needs, people would make the mistake of engaging in them for long-term needs as well, thus transgressing a Torah prohibition (Rambam, Rosh, and Ran; SA 495:2).¹ Others maintain that such melakhot are always prohibited by Torah law, as the Torah permits only melakhot that are primarily intended to provide for that day, while it prohibits melakhot that are primarily intended to provide for the long term (Rashi, Ramban, and Smag; this opinion is also implied in y. Beitza 1:10).

footnotes: ¹ Nevertheless, in the opinion of most poskim, the halakha follows Rabba (Pesaḥim 46b), who maintains that even one who cooks for the weekday is not transgressing Torah law, since the food could technically be enjoyed on Yom Tov if guests would arrive (see 8:1 below). The problem is that when harvesting an entire field, grinding a large quantity of grain, or pressing many grapes, often there is no possibility that Jews will eat it all on Yom Tov. In such a case, all agree that a Torah prohibition is involved. The severity of the transgression depends upon the type of melakha and the size of the local Jewish population.

In brief, seven melakhot are permitted on Yom Tov when done as part of food preparation: 1) kneading (Lash), 2) cooking and baking (Ofeh), 3) slaughtering (Shoḥet), 4) skinning (Mafshit), 5) carrying (Hotza’ah), 6) lighting a fire (Mav’ir), and 7) extinguishing a fire (Mekhabeh). The license to light and extinguish a flame was limited rabbinically (5:1-2 below).

Other melakhot are permitted if done in the way they are normally done at home, and forbidden if they are done in the way they are normally done for commercial purposes or long-term needs: 1) Toḥen (grinding; below 4:2), 2) Borer (separating; below 4:4-5), and 3) Me’amer (gathering; see SA 501:3).

There are other food-related melakhot that are forbidden outright on Yom Tov: 1) reaping (Kotzer), 2) threshing (Dash, which also includes Mefarek [extracting] and Soḥet [juicing]; see below 4:1), 3) winnowing (Zoreh), and 4) trapping (Tzad). Still, some rabbinic prohibitions established to safeguard these melakhot are sometimes permitted for okhel nefesh (7:3 below).

The Principles of the Melakhot / The Principle of Mitokh

There is a basic principle that applies to all melakhot that are permitted for food preparation on Yom Tov: once (mitokh) they are permitted for purposes of food preparation (le-tzorekh okhel nefesh), they are permitted for other purposes as well. This means that when the Torah permitted certain melakhot for food preparation, it did not intend that they be permitted for this purpose only. Rather, once they were permitted for this purpose, they were permitted for all pleasurable purposes on Yom Tov. The statement that “only what every person is to eat, that alone may be prepared for you” (Shemot 12:16) means that only those melakhot whose purpose is food preparation are permitted on Yom Tov; but once they are permitted, they are permitted for other Yom Tov needs as well. In contrast, melakhot that are not connected to food preparation are not permitted at all on Yom Tov. Thus, one may not do melekhet avoda, which is generally done to make a living, whereas melakhot that a person does on a regular basis to prepare food in the home are not considered melekhet avoda, and he may do them even for other Yom Tov needs (Beitza 12a; SA 518:1; MB ad loc. 1).

For example, just as the Torah permitted carrying food and utensils from one domain to another for the sake of the festive meal, so too it permitted carrying for the sake of other things that one enjoys on Yom Tov. Thus, carrying books and clothes or pushing a baby carriage in the public domain is permitted (SA 518:1; see 6:1 and 6:3 below).

Similarly, just as one may kindle a fire to cook and bake on Yom Tov, so may he kindle a fire to provide light or warmth (SA 511:1 and 514:5; see 5:3 below).

Just as one may cook for a Yom Tov meal, so too he may heat up water to wash his hands or do the dishes (SA 511:2).²

footnotes: ² According to most Rishonim, one who carries for no reason violates a Torah prohibition, since permission to carry is limited to cases in which one benefits from it on Yom Tov. If the carrying serves no purpose, it remains prohibited by Torah law. This is the opinion of Rabbeinu Ḥananel, Rabbeinu Tam, Ramban, Rashba, Rosh, Ra’ah, Ritva, and many others (see BHL 518:1 s.v. “mitokh”). Others maintain that any melakha that was permitted for okhel nefesh is entirely permitted by Torah law on Yom Tov. Even the rabbinical prohibition is limited to a case of carrying rocks, because the rocks are muktzehMagid Mishneh). This is the position of Rashi, Rif (according to Ran), and Rambam (according to Magid Mishneh). Some explain that Rif and Rambam maintain that on the Torah level these melakhot are entirely permitted, but rabbinically it is prohibited to perform them for no reason (Pnei Yehoshu’a; BHL 518:1 s.v. “mitokh”). The commentators disagree as to the position of Shulḥan Arukh (518:1).In any case, all agree that Torah law prohibits doing melakha on Yom Tov for the weekday, for a non-Jew, or for an animal (BHL 512:1 s.v. “ein”). It emerges that the disagreement described above is limited to cases in which a person undertakes melakha for no reason. According to those who are lenient, it is permitted; they maintain that the Torah does not require us to evaluate whether the need is great, small, or nonexistent. Rather, as long as a person wants to carry, it is considered a need, and he may do so. Only if the melakha is undertaken for a weekday, for a non-Jew, or for an animal is it forbidden. According to most poskim, these melakhot are permitted only when they meet a Yom Tov need. See 6:1 and 6:3 below for the laws pertaining to carrying.

The Principles of the Melakhot / Melakhot Are Permitted Only for the Sake of Yom Tov

All of the melakhot that are permitted on Yom Tov are permitted only for the sake of Yom Tov; it is forbidden by Torah law to do melakha for weekday needs. Therefore, if one cooks toward the end of Yom Tov, such that the food will not be ready on Yom Tov, he violates Torah law, as he has cooked on Yom Tov for the weekday. If the food will be ready before the end of Yom Tov, he has not transgressed Torah law, since if guests arrive, he could serve them this food on Yom Tov. Thus it is not certain that he cooked for the weekday. However, if he intended to cook for the weekday, he violates rabbinic law (Beitza 17a; Rabba in Pesaḥim 46b; SA 503:1).

One may not cook on Yom Tov for Shabbat either, unless he made an eruv tavshilin (as explained below, 8:1).

Even activities that are not melakhot but still require effort, such as setting the table and washing the dishes, may not be done on Yom Tov for the weekday or for Shabbat (as explained in Peninei Halakha: Shabbat 22:15-16).

If one wants to fry schnitzel for a Yom Tov meal, he may make a bit extra to ensure that there will be enough, and he may then eat the leftovers after Yom Tov. However, he may not intentionally prepare extra in order to have leftovers for the week.

If one wants to heat water for a cup of tea or coffee, he may fill a large pot with water so that there will be hot water after Yom Tov. Similarly, one who wants to cook food may fill a large pot so that he will have leftovers after Yom Tov. Since he is placing the pot on the fire all at once, it is not forbidden to increase the quantities (marbeh be-shi’urim). Nevertheless, he should take care not to state explicitly that he is making extra for the weekday. Furthermore, once the pot has been placed on the fire, he may not add more food or water for the week (SA 503:2; MB ad loc. 15).

If there is a pot of food whose taste will be improved with the addition of more meat or fish, one may add them to the pot even after it has been placed on the fire, and even if he is mainly interested in having leftovers after Yom Tov, since he also wants to improve the Yom Tov meal (SA 503:1; MB ad loc. 6). (See 8:5 below regarding what one who forgot to make an eruv tavshilin may add to the pot on Yom Tov.)

The Principles of the Melakhot / For Non-Jews and for Animals

The melakhot permitted on Yom Tov are permitted for the sake of the mitzva of simḥa of Yom Tov. Therefore, one may cook for other Jews, since they too have a mitzva to rejoice on Yom Tov. However, it is forbidden to cook for non-Jews, who have no mitzva to rejoice on this day, or for animals, as it is written: “Only what every person is to eat, that alone may be prepared for you” (Shemot 12:16). The Sages expound: “for you,” not for non-Jews; “for you,” not for animals. For this reason, the Sages tell us that non-Jews may be invited to Shabbat meals, as there is no concern that the hosts will cook extra for them in a forbidden manner, as cooking is prohibited on Shabbat anyway. However, non-Jews may not be invited to Yom Tov meals, as one may end up cooking extra for them (Beitza 21b).³

footnotes: ³ . In practice, as long as there is the possibility that guests will come and eat what one cooked for non-Jews or for animals, he is not transgressing Torah law; since (ho’il), if Jewish guests arrive, they will eat the food on Yom Tov, one did not necessarily cook for the non-Jews or for the animals. This is the opinion of Rambam (Yom Tov 1:15); Rashba (Beitza 21b); Ran on the Rif; and Ra’ah. In contrast, Me’iri (Pesaḥim 46b) and Shita Mekubetzet maintain that since one’s intension is to cook for the non-Jews or the animals, “ho’il” does not apply, and he violates Torah law.

If a non-Jew arrives uninvited on Yom Tov, then if the hosts have finished cooking by the time he arrives, he may be invited to join the meal, as there is no longer a concern that they will cook extra for him. This applies even if the unexpected guest is an important person, as long as the hosts do not insist that he join them (SA 512:1; Taz; MB ad loc. 10). If one wishes to invite a non-Jew who is interested in conversion to Judaism, he may do so, on condition that it is explained to the potential convert that it is forbidden to cook for a non-Jew on Yom Tov. In this way, there is no concern that the host will cook an additional dish for him, though he may increase the quantity of the existing dishes on his behalf.⁴

footnotes: ⁴ The question of whether it is permissible le-khatḥila to invite a respected non-Jew to the Seder or another Yom Tov meal for the sake of communal welfare requires further study. See Shulḥan Shlomo, 512, n. 8, which records that it was customary to invite consuls and ambassadors, and that this was permitted because it constitutes a great need. In my opinion, this can be permitted under pressing circumstances only if the hosts resolve to finish cooking all the dishes before Yom Tov, just as is done before Shabbat. In this way, the concern that they will cook for the non-Jew is lessened. This can also be combined with the view of most Rishonim that no Torah prohibition is violated when one cooks kosher food for a non-Jew, since other guests may arrive. Here, since the non-Jew’s entire objective is to join a traditional, customary Jewish meal, there is no concern that one would cook non-kosher food for him, so perhaps there was no decree in such cases. If we accept this reasoning, then we may rule leniently even when circumstances are not pressing when the goal of the invitation is for the guest to experience a properly observed Jewish holiday. According to the same logic, one may be lenient with respect to non-Jews who want to convert or who have already joined non-halakhic streams of Judaism, so as to forge a close relationship that will result in a proper halakhic conversion.

A Jew may invite his live-in non-Jewish attendant to join his Yom Tov meal, and he may add food to the pot before placing the pot on the fire. Since the non-Jew is his attendant, the employer is not overly concerned with the need to honor the non-Jew, and there is no concern that he will transgress by adding to a pot that is already on the fire (Rema 512:1; MB ad loc. 11).

The Sages decreed that a Jew who publicly desecrates Shabbat is to be treated like a non-Jew, and consequently one may not cook for him on Yom Tov (MB 512:2). Latter-day poskim, however, rule that this applies only to people who publicly desecrate Shabbat out of spite (lehakhis), whereas the typical non-observant Jew nowadays does not keep Shabbat because he does not properly understand its great importance, not out of spite. Therefore, he is like any other sinful Jew, and one may cook for him on Yom Tov (Peninei Halakha: Shabbat 1:15).

One may not cook for animals. Nevertheless, as we have seen, one who cooks for himself may add some food to the pot for an animal in his charge before he places the pot on the fire (SA 512:3). Other laws pertaining to feeding animals on Yom Tov are the same as those of Shabbat (Peninei Halakha: Shabbat 20:3).

The Principles of the Melakhot / Shaveh Le-khol Nefesh

When melakhot are permitted on Yom Tov for food preparation or other Yom Tov pleasures, they are permitted on condition that one performs them for the sake of something which is shaveh le-khol nefesh, which means that most people derive benefit from it. In contrast, one may not perform melakhot for the sake of something from which only those who are overindulged or ill normally derive benefit. The Torah states: “Only what every person is to eat, that alone may be prepared for you” (Shemot 12:16). This does not necessarily mean that everyone must enjoy it regularly, but that most people, if given the opportunity, would enjoy it. Thus, even though few people have ever trapped a deer and eaten its meat, since most people would be happy to eat the meat, slaughtering it on Yom Tov is considered shaveh le-khol nefesh. Similarly, food may be seasoned with expensive spices that most people cannot afford, because most people would be happy to use them in their food.

In contrast, one may not place incense on coals in order to perfume the room or clothes that one places above the coals, because most people, even if offered the opportunity, would not perfume their homes or clothes in this way. Therefore, one who does so violates the Torah prohibitions of Mav’ir and Mekhabeh (Beitza 22b; Ketubot 7a; 5:10 below).⁵

footnotes: ⁵ See note 2 above, where we explain that according to Rambam and Rashi, all melakhot that are permitted for okhel nefesh are permitted even when there is no need at all. Accordingly, those melakhot are certainly permitted for the needs of overindulged people. In their opinion, the reason that one may not place incense on coals is because of the prohibition of Mekhabeh, not because the scent is not shaveh le-khol nefesh. However, the halakha follows the majority of poskim, who maintain that these melakhot are permitted only for a need that is common to most people. Thus, a melakha for the needs of overindulged individuals violates Torah law. R. Shlomo Zalman Auerbach (Minḥat Shlomo on Beitza 22b) explains that any common human need is permitted, even if only overindulged people need it in a particular way. Thus, one may raise the flames of a furnace even if only overindulged people would consider the room cold, since heating a cold room is a general human need. Likewise, one may add seasoning to make a food extremely spicy, beyond what people would normally eat. See 7:1-2 below for the disagreement about whether the needs of the sick are considered shaveh le-khol nefesh

The Principles of the Melakhot / Cooking More Yom Tov Food than Needed

Even though a Yom Tov meal can be enjoyed with only one dish, one who wishes to enhance his simḥa of Yom Tov may cook many different dishes, as is standard when preparing the most sumptuous of meals.

One who prefers challah fresh from the oven may bake additional challah on Yom Tov, even though he already has day-old challah (MB 506:37). However, since lighting a new fire on Yom Tov is forbidden, he may not turn on the oven. Therefore, a timer (“Shabbos clock”) should be set before Yom Tov to turn on the oven at the appropriate time (see 5:7 below).

One may prepare labor-intensive food on Yom Tov, such as dumplings made from filo dough. He may also cook fruit to make it tastier, even if it can be eaten raw. In general, one may exert effort to improve food’s taste or aroma.

One who wants to dip his challah in gravy may cook meat on Yom Tov in order to produce gravy, since he has no other way to obtain it.

Since a new fire may not be lit on Yom Tov, a candle is lit before Yom Tov, and on Yom Tov that flame is used to kindle the gas burner upon which one can cook. Extinguishing the burner after cooking should be accomplished via grama (an indirect action) or by having the gas on a special timer, as explained below (5:5).

The Principles of the Melakhot / Food That Could Have Been Prepared Before Yom Tov

The basis for the permissibility of doing melakha on Yom Tov is to prepare and improve dishes and thereby enhance the simḥa of the festival. The taste of fresh bread from the oven cannot be compared to the taste of day-old bread; the taste of freshly fried schnitzel or freshly baked potatoes cannot be compared to that of schnitzel or potatoes prepared yesterday. Food made today – whether cooked, fried, or baked – is generally better than food made yesterday. Since food may be prepared on Yom Tov in order to make the festival more enjoyable, one need not try to prepare everything beforehand. Even for the first night of Yom Tov, the cooking may be done after Yom Tov begins. One might think that this should not be the case, since if one were to cook that food shortly before the start of the festival, it would be almost as fresh and tasty. Nevertheless, we do not draw distinctions between the meals, and any food that is better fresh may be cooked on Yom Tov. Even nowadays, when refrigerators preserve cooked and baked food better than anything available to the Sages, the permissibility remains, because the food on its own, without the aid of appliances, is better when it is made shortly before it is served.

All this applies to food whose taste is somewhat compromised if prepared a day in advance. In contrast, food whose taste is not impaired over the course of a day must be prepared before Yom Tov. For example, if one wants to have ice cream or compote on Yom Tov, he must prepare them in advance, since doing so does not affect their flavor at all. Nevertheless, if he did not prepare them before Yom Tov, he may prepare them on Yom Tov with a shinui. The shinui does not have to be a major one, as the point is just to remember that it is Yom Tov, so that one does not end up doing forbidden melakha (Levush 504:1). For example, if one generally prepares the food directly on the table, he may put down a tablecloth or a tray and prepare the food on them. If one could not prepare the food before Yom Tov due to circumstances beyond his control, he may prepare it normally on Yom Tov, with no need for a shinui (MB 505:10; SHT ad loc. 8).

This law applies to all melakhot like Borer which are permitted on Yom Tov for purposes of food preparation. If one can do them before Yom Tov without impairing the food, he must do so. If he did not prepare them beforehand, he may do so on Yom Tov with a shinui.⁶

footnotes: ⁶ It is true that according to Ramban, Rashba, and Rosh, it is permitted to cook on Yom Tov even if the food could have been cooked earlier and would have been just as good. However, according to most Rishonim, in such a case it is forbidden to cook on Yom Tov. Some say the prohibition is one of Torah law (Smag; also implied by Or Zaru’a), while many others maintain that the prohibition is rabbinic (Yere’im; Ritva; Maharil; Raavya; Roke’aḥMaharaḥ Or Zaru’aSha’ar Ha-tziyun (495:5) states that this is the opinion of most poskimSA 495:1 appears to rule leniently, while Rema is stringent. Indeed, all the Ashkenazic Aḥaronim are stringent about this issue. Many Sephardic poskim are stringent as well; see Shiyarei Knesset Ha-gedola (OḤ 495, Hagahot Beit Yosef 4-6, adding that SA is not explicitly lenient), Pri Ḥadash (495:1), Birkei Yosef (495:2), and Ḥazon Ovadia (Yom Tov, p. 8). In contrast, Or Le-Tziyon (3:19 n. 1) allows Sephardim to be lenient even le-khatḥila. Since all Ashkenazic poskim and many Sephardic ones are stringent, that is the ruling written above. If one did not prepare the food before Yom Tov, some are stringent (Or Zaru’a and Maharil, as cited in Darkhei Moshe 495:2), but Rema writes (based on Smag, Yere’im, and Roke’aḥ) that one may prepare it on Yom Tov with a shinui.The Sages did not forbid cooking on Yom Tov for the nighttime meal, even though the cooking could have been done right before Yom Tov without affecting the taste, because the general principle is that any food that will get a little worse over the course of the day may be cooked on Yom Tov. It is still permitted to cook such food nowadays, even though we have refrigerators, because without these appliances the food would get worse in the course of a day (SSK, introduction ch. 3, n. 26).In practice, almost every food is better when it is prepared on the day it will be served; only if there is no difference must one prepare it before Yom Tov.

The Principles of the Melakhot / Items Necessary for Food Preparation

In principle, on Yom Tov one may repair makhshirei okhel nefesh, items that are necessary to prepare food on Yom Tov. However, for a variety of reasons, in practice we almost never permit repairing makhshirei okhel nefesh on Yom Tov. First, when the repair could have been done before Yom Tov, it is prohibited by Torah law to do it on Yom Tov (Beitza 28b). Second, according to some authorities (Ha-ma’or and Ran), the permissibility is limited to cases where the repair is partial, whereas a complete repair is prohibited. In many cases, it is difficult to determine which category a specific repair would fit into. For example, the permissibility of sharpening a knife is disputed, with many maintaining that one may not do so because it is considered actually creating a kli (SA 509:2). Third, when the repair is not necessary because the food could be prepared even without it, albeit with difficulty, one may not repair the item, as doing so is deemed an excessive and unnecessary effort (Rema 509:1). Fourth, only something that is one step removed from actual food preparation may be repaired, while something two steps away (makhshirei makhshirim) may not be repaired. For example, one may not shave down a key in order to unlock the door of a room in which food is located, since the key itself is not necessary for food preparation. It only allows access to the food.

Additionally, even in a case where it is clear that one may repair something used in food preparation, in practice the Sages generally did not allow it, out of concern that as a result of being lenient when it comes to repairing items for okhel nefesh that could not have been repaired before Yom Tov, people will end up repairing items on Yom Tov that could have been repaired beforehand, thus transgressing a Torah prohibition (Beitza 28b; Rema 509:1). Therefore, a student of halakha who knows when repairs are permitted may act in accordance with his knowledge, but if one comes to a rabbi with a question about a particular case without studying the entire issue, he should not be given permission, because he might end up being lenient about what is prohibited.

Nevertheless, when a repair is absolutely necessary for food preparation, the Sages explicitly ruled leniently (Ramban). Therefore one may sweep plaster out of his oven if it is causing the food inside to burn, on condition that he could not have done so before Yom Tov. That would be the case, for example, if the plaster caused the problem on Yom Tov itself, or if one was unaware of the problem before Yom Tov (Beitza 28b; SA 507:4). It seems that the Sages felt that the grounds for permitting this necessary repair were easily understandable, so they were not concerned that people would extrapolate incorrectly and permit the forbidden.⁷

footnotes: ⁷ According to the Gemara, the Sages forbid repairing makhshirei okhel nefesh on Yom Tov, whereas R. Yehuda maintains that items which could not have been repaired before Yom Tov may be repaired on Yom Tov itself. This would be the case if the items broke on Yom Tov or if their owner was unaware that they broke before Yom Tov (Beitza 28b). R. Ḥisda declares that the law follows R. Yehuda. However, the Gemara also recounts stories of Amora’im who, while agreeing that this is the law, did not rule accordingly for those who inquired (Beitza 28a-b). On the other hand, elsewhere the Gemara seems to follow the Sages, ruling that one may not extinguish a burning log on Yom Tov in order to keep the house from becoming smoky (Beitza 22a).The Rishonim disagree about this law as well. Some argue that in practice one should follow R. Yehuda (Ra’avad and Ri’az), while others rule that the law follows the Sages (Or Zaru’a, Magid Mishneh’s understanding of Rambam). The vast majority of Rishonim maintain that the law follows R. Yehuda, but that those who ask should not be told so. This is the position of Behag, Ha-ma’or, Yere’im, and Smag. It is also implied by Rif and Rambam (according to most commentators). Ramban (in Milḥamot Hashem) explains the opinion of the Gemara and most of the Rishonim, namely, that the law technically accords with R. Yehuda, but unless there is a great need, this ruling is not rendered. This explains why sweeping out one’s oven is permitted even le-khatḥila (since it is absolutely necessary), while sharpening a knife is permitted only partially and theoretically (since it is not so necessary). Actions that are not directly connected to okhel nefesh – extinguishing a log in order to prevent the house from getting smoky, or extinguishing a candle in order to allow marital relations – are not permitted at all, out of a concern that people would end up being lenient even when there is no room for leniency, as is explained in Beitza 22a. This is also the opinion of Rashba, Ran, Rosh, and many other Rishonim, as well as many Aḥaronim. See Harḥavot here. Furthermore, there are additional uncertainties as to which repairs are partial and which are complete, which are truly necessary and which are not. Thus it emerges that, in practice, we are almost never lenient when it comes to repairing makhshirei okhel nefesh. This seems to be the position of Shulḥan Arukh, which on the one hand states explicitly that the law follows R. Yehuda (495:1) and that one may sweep out his oven (507:4), yet on the other hand forbids repairing a skewer or sharpening a knife (509:1).

The Principles of the Melakhot / Koshering Utensils on Yom Tov

Dishes, crockery, or utensils that have become forbidden to use, whether on account of having absorbed the taste of meat and milk or on account of having absorbed the taste of non-kosher meat, may not be koshered on Yom Tov. The specifics of the absorption are immaterial; whether the absorption involved liquids (in which case the koshering process involves hagala) or was through fire (as in the case of a baking pan or skewer, in which case the koshering process requires heavy libun), one may not do the koshering. This is because making the item usable looks too much like repairing it (SA and Rema 509:5). True, if the utensil could not have been koshered before Yom Tov, and it is needed, it may be koshered on Yom Tov following the laws for makhshirei okhel nefesh. However, this law should not be taught publicly, because of a concern that some of the audience will end up being lenient in other matters, where there is no room for leniency (MB 509:24, 26).

As is known, crockery and cutlery that a Jew acquires from a non-Jew require immersion in a mikveh. Until they have been immersed, they may not be used. Rishonim disagree as to whether a utensil may be immersed on Shabbat and Yom Tov. Some forbid doing so, because it looks like “repairing” the item (Rosh). Others permit it, as this is not a full repair, because be-di’avad, if the utensil was used prior to immersion, the food in it is not prohibited (Rif). In practice, if a trustworthy non-Jew is available, it is proper to gift him with the utensil and then borrow it from him, because as long as an item belongs to a non-Jew, it does not require immersion (Peninei Halakha: Shabbat 22:6).

If no non-Jew is available, the disagreement remains unresolved. However, on Yom Tov, even those who are stringent agree that technically, as long as one could not have immersed the utensil before Yom Tov, he may immerse it on Yom Tov. For we have seen that it is permitted to repair makhshirei okhel nefesh on Yom Tov. In practice, though, according to those who prohibit immersing utensils on Shabbat, a rabbi should not tell an inquirer differently on Yom Tov, out of concern that he will not understand the reasoning behind the permit and will end up mistakenly permitting other cases as well (MA; Eliya Rabba; MB 509:30).⁸

footnotes: ⁸ If the utensil requires immersion only rabbinically, for example if it is made of glass, the immersion is not considered much of a repair, and even according to the stringent view one may tell those who ask that it is permissible to immerse it (Pri Megadim; MB 509:30).