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). 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).
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).