Gemara

22b - Question: May one fumigate produce (in smoke of spices, to flavor it)?

Answer #1 (Rav): It is forbidden (because only finicky people do so).

Answer #2 (Shmuel): It is permitted (everyone would like it, just not everyone can afford it).

Rav Huna: It is forbidden because it extinguishes (when one puts spices on the coals. Also, afterwards the spices burn.)

Rav Yehudah: It is forbidden to fumigate on coals, but it is permitted on (very hot) Cheres (earthenware).

Rabah: It is forbidden even on Cheres, for it scents (the Cheres).

Rava: It is permitted even on coals, just like one may roast meat over coals (even though this extinguishes, burns and scents, it is permitted for food).

23b - Mishnah: One may not trap fish from a Biver (an enclosure of game) on Yom Tov. One may trap a Chayah or bird (from a Biver).

R. Shimon ben Gamliel says, not all Bivrin are the same. The rule is, one may trap only what can be trapped without exertion.

24a - Rav Yosef: The Halachah follows R. Shimon ben Gamliel.

Rishonim

Rif and Rosh (2:22): We conclude like Rava, who permits to fumigate on coals, just like one may roast meat over coals.

Rif: The Halachah follows R. Shimon ben Gamliel.

Rambam (Hilchos Yom Tov 1:4): Hotza'ah and burning are permitted on Yom Tov even if not needed for eating. All other Melachos are permitted only for the sake of eating, such as Shechitah, baking and kneading. What is not needed for eating is forbidden, such as writing, weaving and building.

Lechem Mishneh: The Magid Mishnah understands that the Rambam exempts any Melachah done for a need, even writing or weaving. This cannot be.

Rambam (5): Chachamim forbid on Yom Tov any Melachah that could be done before Yom Tov without a loss, even if it is for eating. This is a decree lest people leave Melachos that could be done beforehand for Yom Tov. If he will do much Melachah on Yom Tov he will refrain from Simchas Yom Tov and not have time to eat and drink.

Rebuttal (Ra'avad): The concern is lest he cause himself extra exertion on Yom Tov.

Sefer ha'Chinuch (315): The Torah wants Benei Yisrael to be free on Yom Tov so parents can tell children about the miracles Hash-m did for us, and to gather in the Beis ha'Keneses or Beis Medrash to hear Divrei Chachamim.

Rambam (6): Chachamim did not forbid Hotza'ah on Yom Tov, even though it could be done beforehand, because they wanted to increase Simchas Yom Tov. A person may take with himself whatever he needs.

Rambam (7): Harvesting, Borer, grinding wheat and sifting are forbidden, for they could be done beforehand.

Rambam (8): We may knead, bake, be Shochet and cook, for these are better when done the same day. Also Machshirin that are not as good if done the previous day, such as grinding spices, are permitted.

Rebuttal (Ra'avad): Produce is better if it is picked the same day. Why is this forbidden? The Yerushalmi learns from the Semichus of "Ach Asher Ye'achel l'Chol Nefesh" to "U'Shmartem Es ha'Matzos", that only Melachah with what is detached is permitted.

Answer (Magid Mishnah 5): The Rambam holds that if there is no loss in one aspect of the Melachah, e.g. harvesting grain, Chachamim forbade the entire Melachah. It seems to me that Meleches Avodah is anything that people normally do through slaves or hired workers.

Rambam (2:7): If fish, Chayos or birds are in a big Biver, and one must bring a trap to trap them, one may not do so on Yom Tov.

Rambam (Hilchos Yom Tov 4:6): One may fumigate produce on Yom Tov.

Rosh (3:1): One may not trap on Yom Tov something that requires exertion. Rashi connotes that this is mid'Oraisa. This is unlike Shechitah, baking and cooking, because they are better if done the same day. One could trap from before Yom Tov and leave the animal in the trap. However, the Gemara (28b) distinguishes between Machshirim that could be done the previous day and those that could not. This implies that there is no distinction regarding Ochel Nefesh. From R. Yehudah we infer that Chachamim do not distinguish (mid'Oraisa). Rather, Chachamim decreed against harvesting and grinding, for a person normally harvests his entire vineyard or field at once, and grinds much (grain) or presses many grapes at a time. Therefore, Chachamim forbade these because they resemble Uvda d'Chol (weekday actions). The same applies to trapping. The Yerushalmi makes an Asmachta to forbid grinding, Borer and sifting from "Ach Asher Ye'achel l'Chol Nefesh...; "U'Shmartem Es ha'Matzos". I.e., only Melachos from kneading and onwards are permitted. Chizkiyah expounds "Ach" and "Levado" to exclude (forbid) harvesting and sifting.

Ran (DH Ein): If Rashi forbids trapping on Yom Tov mid'Oraisa, this is wrong. The Torah does not forbid Ochel Nefesh because it could have been done before Yom Tov. On Yom Tov we may bring a Shechitah knife to the animal, even though on Shabbos we may not bring a Milah knife to the baby, because it could have been done before Shabbos. Grinding salt and saffron is a Melachah mid'Oraisa; one is liable for it on Shabbos. Nevertheless it is permitted on Yom Tov, just Chachamim required a Shinuy because it could have been done before Yom Tov. The Gemara forbids making cheese on Yom Tov for the same reason; this is only mid'Rabanan. Perhaps Rashi teaches why it is forbidden mid'Rabanan. He does not explain why it is forbidden on Yom Tov if he set a trap from before Yom Tov but did not catch anything. Also, fish caught in a trap from before Yom Tov would get spoiled more than spices ground from before Yom Tov, yet the latter is permitted. Also, some fruits such as strawberries and figs would deteriorate if picked the day before, yet it is forbidden on Yom Tov. Rather, there must be another reason. The Yerushalmi learns from "Ach Asher Ye'achel...; U'Shmartem Es ha'Matzos" that only Melachos from kneading and onwards are permitted. Chizkiyah expounds "Ach Hu Levado" to exclude harvesting, grinding and sifting. They argue about Breirah. The Yerushalmi forbids these mid'Oraisa. This is unlike our Gemara which permits dicing peppers and mashing Nidochin (things normally mashed) in the usual way. The Yerushalmi says that Beis R. Gamliel diced peppers in a grinder because this was not the normal way.

The Ramban says that only Tikun Ochel is permitted on Yom Tov. Trapping and detaching produce are forbidden because they are Meleches Avodah, or like the Yerushalmi says. This does not answer why grinding wheat is forbidden, but dicing peppers and mashing Nidochin, Toldos of grinding, are permitted without a Shinuy. It seems that the Bavli permits all Melachah for food mid'Oraisa. Mid'Rabanan, it forbids things normally done at once for a long time. Even though people do not pick strawberries and figs for a long time, we follow the majority of produce, which is harvested at once for a long time. Chachamim did distinguish dicing peppers and mashing Nidochin from grinding because they are done differently. Mashing is done in a mortar, and grinding is done in a mill. People usually trap in advance, since they are not assured of catching what they need on the day. A Beraisa lists making cheese and removing honey from a hive among Melachos for which b'Shogeg one is Chayav Chatas on Shabbos, and he is lashed if he was Mezid on Yom Tov. Just like lashes do not apply to making cheese, perhaps the same applies to removing honey, which is a Toldah of detaching. It seems that also the Rambam permits all food preparation mid'Oraisa on Yom Tov. However, the Yerushalmi and the above Beraisa suggest that some is forbidden mid'Oraisa.

Poskim

Shulchan Aruch (OC 495:1): Every Melachah forbidden on Shabbos is forbidden on Yom Tov, except for Melachah for Ochel Nefesh, Hotza'ah, burning, and Machshirei Ochel Nefesh that could not have been done before Yom Tov.

Rema: Some are stringent about Ochel Nefesh itself if the taste would not be any worse if it was done before Yom Tov. However, if he did not do it before Yom Tov and there is a need for it on Yom Tov, it is permitted through a Shinuy.

Kaf ha'Chayim (11): One may not make cheese because it cannot be done through a Shinuy, so it is Uvda d'Chol.

Shulchan Aruch (2): Chachamim forbade harvesting, grinding, squeezing and trapping, even though they are Melachos of Ochel Nefesh.

Beis Yosef (DH u'Mah she'Chosav v'Chen): These are forbidden because they are normally done at once for a long time. Trapping is different. It is forbidden because sometimes a person catches much fish in his trap, and it looks like Uvda d'Chol.

Taz (2): I do not know why the Tur says that the verses in the Yerushalmi are an Asmachta. One is lashed for these Melachos!

Gra (DH Asrum): The Rashba holds that the Torah authorized Chachamim to decide which Melachos are permitted.

Mishnah Berurah (13): These are forbidden even through a Shinuy. Many Poskim say that they are forbidden mid'Oraisa.

Shulchan Aruch (500:3): One may cut a hole in meat for a Siman.

Be'er Heitev (8): The Shevus Yakov permits even to form words. One should use as great a Shinuy as possible to avoid Uvda d'Chol.

Rebuttal (Mishnah Berurah 17 and Sha'ar ha'Tziyon 20): The Maharil and Me'iri forbid letters and pictures. Even Melachos of Ochel Nefesh are permitted only from kneading and onwards. Other Melachos are forbidden like on Shabbos, including Shevus.