Siman 504

Even though food preparation that could have been done on the eve of Yom Tov is forbidden to be done on Yom Tov by Torah law or by rabbinic decree, according to the opinions explained in siman 495, and certainly so regarding the adjuncts of food preparation, nevertheless our sages, of blessed memory, said (14a) that one may crush spices in their usual manner on Yom Tov, even though crushing is a subcategory of grinding, and even though one could have crushed them on the eve of Yom Tov. And the reason is that since they deteriorate in their flavor if one prepares them yesterday, it is considered as if it were impossible to prepare them on the eve of Yom Tov, and it is permitted to crush them even if we consider them as adjuncts, and even if he knew yesterday that he would require those spices.

Therefore, it is forbidden to crush salt in its usual manner, because salt does not spoil if it is prepared from yesterday. Therefore, it is forbidden to crush salt on Yom Tov except by means of a shinui, such as crushing it on the table or in a bowl, but not in a mortar. And if it is only possible in a mortar—he should tilt it on its side during the crushing. And so too, if there is a type of spice that does not spoil if it is prepared from yesterday, such as morika which is called saffron, and he knew yesterday that he would need it—he should not prepare it except by means of a shinui like salt. And so too peppers and their like (Magen Avraham subsection 1 in the name of Yam Shel Shlomo, and Bach and Maharil). But garlic certainly spoils, and it is permitted to crush it on Yom Tov. And so too onions and all their like. And some hold that despite all this, even in the crushing of spices one needs a slight shinui, if he knew yesterday that he needed them. And some are concerned even if he did not know (see Magen Avraham subsection 4). And it is proper to be concerned for this, so that because of this he will remember that it is forbidden to crush more than what is needed for Yom Tov (ibid. in the name of the Semag). But the primary ruling is according to the first opinion.

Among them, there was a specific mill for grinding peppers and for mustard. And even now, we have for peppers and for coffee—like a small mill, and it is forbidden on Yom Tov to grind there even by means of a shinui, because this is truly a weekday activity, and it would be a blemish to the Yom Tov. Rather, one crushes in a mortar or with a pestle—like all spices. And it is permitted to bring spices and the pestle to the mortar, or the mortar to them, even through a public domain, even though it is possible to do so from the eve of Yom Tov. And the reason has already been explained in siman 498 regarding the matter of bringing an animal to the slaughterer, because regarding the matter of carrying, they opened the way completely. See there, and at the beginning of siman 495.

The Rambam wrote in the third chapter: One may not crush grain in a large mortar, but in a small mortar it is permitted, for this is its shinui. But in the Land of Israel, it is forbidden even in a small one, for their grain is good, and if one crushes it on the eve of Yom Tov – there is no loss in this. Thus far his words. And in the Gemara there, it is explained according to one resolution that in a place where people are lax regarding prohibitions – it is also forbidden in a small one in every place. However, besides this, the Tur and the Shulchan Aruch in section 3 wrote that since we do not know what is called "large" and what is called "small" – therefore, in all manners it is forbidden. And it is simple that now the custom is to completely prohibit the crushing of groats.

And our teacher, the Rema, wrote there that it is permitted to grate cheese on Yom Tov on a vessel that is like a sharp threshing sledge, and in our language a "reib-eisen." However, it requires a slight change, like the crushing of salt. And the same law applies to matzot without a change, because there is no grinding of foods that were previously ground. Thus far his words, meaning: that there is no grinding after grinding. And the matzah was already ground into flour.

And there is one who wrote regarding this that it is not comparable to mustard, which is forbidden to grind in a mill, for there they are accustomed to grind a large amount together, and it resembles a weekday activity. But here, it is not the way to grate except for what is needed for the moment. And according to this, the horseradish that they call "krain" – it is forbidden to grate it on Yom Tov, for it is the way to grate a large amount for two or three days (Magen Avraham, subsection 7). And the matter is very astonishing, for you have nothing that is destined to spoil like krain, as is known. And it is obvious that it is permitted to grate it on Yom Tov, and such is the custom of the world (and so wrote the Eliyah Rabbah). And also that which he compares to a mustard mill is astonishing, for this vessel of a sharp grater does not have the form of a mill at all, as is known. This is not the case with a mill for peppers or for mustard – it is somewhat in the form of a mill, and what is the connection of this to that?

And even though measuring flour is forbidden on Yom Tov, as I wrote in siman 506, nevertheless, a person is permitted to measure spices to put into a pot so that he does not spoil the dish, for this is like actual ochel nefesh, and likewise salt and peppers. However, in a place where even on a weekday they do not measure, but only give by estimation—it is also forbidden on Yom Tov. But in a place where on a weekday they give by measure—it is also permitted to measure on Yom Tov.