Gemara

Mishnah - Beis Shamai: One may crush spices using a wooden pestle. One may crush salt in a receptacle using a wooden ladle;

Beis Hillel say, one may crush spices normally with a stone pestle. One may crush salt using a wooden pestle.

Gemara - Question: All require a Shinuy for salt. What is the reason?

Answer #1 (Rav Huna or Rav Chisda): All foods require salt, but not all require spices (one should have prepared salt, for he knew that he will need it);

Answer #2 (the other of Rav Huna and Rav Chisda): All spices weaken if they are crushed in advance; salt does not weaken.

Question: What do they argue about?

Answer: They argue about one who knew that he will need spices. Alternatively, they argue about saffron (it does not weaken).

Shmuel: One may crush all Nidochim (things normally crushed) normally, even salt.

Question: The Mishnah requires a Shinuy for salt!

Answer: Shmuel holds like the following Tana:

Beraisa - R. Meir: Beis Shamai and Beis Hillel agree that one may crush Nidochim normally together with salt. They argue about crushing salt by itself. Beis Shamai say that one crushes in a receptacle using a wooden ladle for meat that will be roasted (i.e. a small amount), but not for cooking meat in a pot;

Beis Hillel permit using anything.

Objection: This cannot be (surely, we may not use Muktzah)!

Correction: Rather, they permit (to crush normally) for any need.

Rav Acha Bardela (to his son): When you crush, tilt the bowl (a small Shinuy).

Rav Sheshes heard crushing. He said 'it is not from my house'.

Question: Perhaps the bowl was not tilted!

Answer: He could tell from the sound that it was not.

Question: Perhaps they were crushing spices!

Answer: He recognized that it was the sound of salt being crushed.

Rishonim

Rif and Rosh (1:21): Shmuel permits to crush all Nidochim normally, even salt. Rav (according to our text, Rav Acha Bardela) said to tilt the bowl while crushing. This refers to salt. This is supported by the questions about Rav Sheshes. After establishing that the bowl was not tilted, we ask that perhaps they were crushing spices, i.e. this is permitted without a Shinuy. BaHaG rules like this.

Rosh: We do not know which answer (why spices are more lenient) the Halachah follows. Therefore one must use a Shinuy whenever he knew what he will cook. We cannot say that since it is mid'Rabanan we are lenient, for then we would adopt both leniencies!

Ba'al ha'Ma'or: Likewise, we require a Shinuy for saffron.

Rebuttal (Milchamos Hash-m): The answers apply to our Mishnah. We rule like the Beraisa, which permits all Nidochim normally. This includes saffron and spices that one knew that he would need.

Question (Ran DH v'Chosav): Even though we rule like the Beraisa, we require a Shinuy for salt. We must explain the reason, to know whether it also applies to other things!

Answer #1 (Ran): It seems that this was a mere stringency of Amora'im. If it was Asur, Rav Sheshes would not have said 'it is not from my house'. The stringency is only regarding salt, for both reasons always apply (it does not weaken, and all foods need salt). Also, salt is very fine and is easily crushed while tilting the bowl.

Rebuttal (Kesef Mishneh, Hilchos Yom Tov 3:12): If it was a mere stringency of Amora'im, why did the Rif rule that a Shinuy is required?

Defense (Taz OC 504:1): The Ran said 'it seems to me that this was a mere stringency...' He did not say that this is the Rif's opinion.

Answer #2 (Kesef Mishneh): The Rif rules like the opinion that requires no Shinuy for spices because they weaken, for we clearly see that this is so. Therefore, when Shmuel said that salt is crushed normally, he meant without a big Shinuy. A small Shinuy is required. However, if so the Rif and Rambam should have required a Shinuy for saffron! Perhaps the Rambam indeed does, for he said that salt requires a Shinuy because it does not weaken. However, the Magid Mishnah says unlike this, and the Rif does not mention weakening. Perhaps they say that saffron weakens a bit. The Gemara said that it does not according to the Mishnah, which requires a big Shinuy. and Rosh needed for saltit is permitted!like brought

Question (Ran DH v'Ika): Surely, crushing spices and salt is Ochel Nefesh, not Machshirin (Machshirin possible from before Yom Tov are forbidden on Yom Tov). If so, why is a Shinuy required? No Shinuy is required for Ochel Nefesh!

Answer (Ran): People often crush spices and salt for many days at once. It is prone to look like he crushes for Chol. Therefore, a Shinuy is required. However, we cannot blame someone for not crushing spices beforehand. Whenever he should have prepared beforehand we require a Shinuy. Similarly, one must chop wood with a Shinuy (31a) because it is done for many days at once and it looks like he chops for Chol.

Hagahos Ashri: One should not crush spices with the usual pestle, for this is a weekday act.

Rambam (Hilchos Yom Tov 3:12): One may crush spices normally, for they would weaken if they were crushed before Yom Tov. One may not crush salt unless he tilts the mortar or crushes in a bowl, for a Shinuy. This is because salt would not weaken if it was crushed before Yom Tov.

Poskim

Shulchan Aruch (OC 504:1): One may crush spices normally, for they would weaken if they were crushed before Yom Tov.

Magen Avraham (1): The same applies to all Nidochim, such as garlic and cress. Some require a Shinuy for peppers and saffron, for they do not weaken.

Mishnah Berurah (1,9): It is Asur to grind spices or coffee; some say that it is Asur mid'Oraisa. Crushing is permitted.

Shulchan Aruch (ibid.): One may not crush salt unless he tilts the mortar or crushes in a bowl, for a Shinuy. This is because salt would not weaken if it was crushed before Yom Tov.

Question #1 (Beis Yosef DH u'Mah she'Chosav Rabeinu): The Tur cites the opinion of Tosfos, who is concerned for both answers. If so, he should have said that saffron is like salt!

Answer (Taz 1): Indeed, the Tur does! He requires a Shinuy for 'spices and peppers' if one knew that he will need them. This refers to spices that weaken, like peppers. Other spices always require a Shinuy.

Question #2 (Beis Yosef DH v'Yesh): Tosfos holds that the Halachah does not follow Shmuel. If so, salt should require a big Shinuy, i.e. a wooden pestle. The Tur says that it suffices to tilt the bowl!

Answer (Beis Yosef): The Tur holds that the Shinuy of tilting the bowl is just as good as the Shinuy of a wooden pestle.

Mishnah Berurah (5): The Isur to crush salt is only for ocean salt which was coarse from the beginning. Letter of the law, one may crush salt that was fine and is now coarse; some are stringent due to Mar'is ha'Ayin.

Mishnah Berurah (6): One may crush salt together with spices, for it is all one exertion.

Kaf ha'Chayim (10): For Shabbos, a big Shinuy is required.

Kaf ha'Chayim (11,12): If one normally crushes in a bowl, this is not considered a Shinuy. L'Chatchilah, one should crush before Yom Tov all the salt he will need.

Mishnah Berurah (8): One should be stringent regarding spices that do not weaken, especially if he knew that he will need them.

Shulchan Aruch (ibid.): One should not mince peppers or mustard in their usual grinder, for this is a weekday act. Rather, he crushes them using a pestle, like spices.

Magen Avraham (3): The Mordechai forbids because the grinder contains a sifter. The Yam Shel Shlomo says that it is only a stringency, but one should be stringent.

Rema: The custom is to make a small Shinuy when crushing spices. It is proper to rule like this.

Mishnah Berurah (11): This is not letter of the law; it is a stringency, lest people not realize when a Shinuy is required or lest they crush more than is needed for Yom Tov. This does not apply to garlic, onions and cress, for even if he knew that he will use them he cannot crush them beforehand, lest they spoil.