Please read the following excerpt from “MBY Archives” from the beginning of Hilchos Yom Tov (MBY 495:1-4):
“2) Machshirei ochel nefesh (preparatory actions for food preparation) There is a category of melachos that a person does as a preliminary step to food preparation, such as sharpening a spit for roasting. The halacha does not permit any such melachos unless they could not have been done before Yom Tov, e.g. the spit became dulled on Yom Tov. More on this category is discussed in simanim 508 and 509.”
Well, guess what? We’re at simanim 508 and 509! Now, many of the cases in these two simanim are not common to our modern kitchens. However, I would like to cover at least the basic topic of ‘machshirei ochel nefesh’ – this category of “preliminaries” - which was mentioned in the preceding excerpt. To do this, we will actually learn a piece of Gemara, followed by two Mishnayos and some explanatory notes. Ready?!
(Many of the notes are courtesy of the Schottenstein Edition of the Talmud Bavli and the Artscroll Mishnah Series.)
A. Gemara Beitzah 28b
Rav Chisda, and others say it was Rav Yosef, expounded: In the case of either a knife that became nicked, or a spit whose tip broke off, or of shoveling out an oven or double-stove on Yom Tov, we come to the dispute between R’ Yehuda and the Rabbis. For it was taught in a Beraisa: “There is no difference between Yom Tov and Shabbos except in regard to food preparation (‘ochel nefesh’) alone. R’ Yehuda permits even melachos that are “preliminaries” of food preparation (‘machshirei ochel nefesh’).” What is the reason that the Tanna Kamma (first Tanna-sage) prohibits all preliminaries? The verse states (Shmos 12:16): “…only that (Heb. ‘hu levado’) may be done for you” – implying that only actual food preparation is permitted, but not its preliminaries. But R’ Yehuda expounds a different word in this verse: “…for you” (Heb. ‘lachem’) – implying for all your needs! … But, R’ Yehuda, is it not written “only that” (which implies an exclusion)? There is no difficulty (in R’ Yehuda’s view.) Here (with the words “only that”) the Torah excludes preliminaries which could have been done before Yom Tov (e.g. the tip of the spit broke before Yom Tov and there was time to repair it then, but he did not do so); whereas, here (with the words “for you”) the Torah includes preliminaries that could not have been done before Yom Tov (e.g. the tip of the spit broke off on Yom Tov itself)!
Summary (part 1): The Rabbis and R’ Yehuda have a dispute: The Rabbis hold that all melachos which are “preliminaries” are prohibited on Yom Tov. R’ Yehuda differentiates: Those “preliminaries” that could not have been done before Yom Tov are permitted to be done on Yom Tov, while those “preliminaries” that could have been done before Yom Tov are prohibited on Yom Tov.
Armed with this Gemara background, let us now learn the two Mishnayos which form the backbone of these two simanim.
B. Mishnah Beitzah
3:7): “We may not sharpen the knife1 on Yom Tov2, but we may sharpen one against the other3.
4:5): “We may not break a shard nor cut a piece of paper4, to roast salted fish on it; nor may we rake out an oven or a double-stove5…”
1The sharpening of a knife is classified as ‘mesaken’/repairing, which is a sub-category of the melacha of ‘makeh b’patish’ (striking the final hammer blow).
This is the opinion of the Rabbis who do not permit labor related to the preliminary stages of food preparation, such as the ones involved in the repairing of utensils needed for food preparation. R’ Yehuda disagrees with the principle of the Mishnah and permits even preliminary food preparation if they could not have been done before Yom Tov - e.g. fixing a utensil that was damaged on Yom Tov. Accordingly, R’ Yehuda would permit sharpening a knife that became dulled or chipped on Yom Tov.
3Sharpening in this manner is permissible because this is a deviation from the usual method (Heb ‘shinui’), even according to the opinion of the Rabbis. 4 Mishnah Berura writes in his introduction to siman 509 that this statement of the mishnah is not solely the opinion of the Rabbis – indeed, even R’ Yehuda agrees to this prohibition! As proof to this, note that the case of “breaking the shard” is not listed in the above Gemara as disputed between the two opinions, as is the case of repairing the knife or spit! The reason this case is stricter is because it is not a case of repairing a utensil; rather, it is a case of creating a utensil. 5This statement once again accords solely with the opinion of the Rabbis. Raking out the stove falls into the category of ordinary ‘machshirei ochel nefesh’ which would not be prohibited according to R’ Yehuda (assuming it could not have been done before Yom Tov), with whom the halacha accords.
Summary (part 2): The dispute between the Rabbis and R’ Yehuda is specifically in regard to those preliminaries that are classified as “repairing tools”. Preliminaries that are classified as ”creating tools” are prohibited according to all opinions. Thus, while the halacha rules leniently in accordance with R’ Yehuda in the case of repairing tools, it nonetheless prohibits creating new ones.
(IMPORTANT: The Shulchan Aruch, Rama and Mishnah Berura caution us with two caveats concerning reliance on R’ Yehuda’s opinion of ‘machshirei ochel nefesh’: 1) It is difficult to apply the distinction between repairing and creating; thus one should act stringently in this matter; 2) The Gemara states that even though we follow R’ Yehuda’s opinion, we should not publicize it, because people will not always be true to the distinction between a repair that could have been done before Yom Tov and one that could not. Thus it is best to avoid such repairs on Yom Tov whenever possible.)
Here, we present another topic addressed in 509:7 by way of excerpt from “MBY Archives” [MBY 323:5-7 Borrowing and acquiring goods on Shabbos, etc. (part 2)]
3) ‘Toveling’ dishes in a mikvah. Generally-speaking, ‘toveling’ dishes on Shabbos and Yom Tov is prohibited, even for the sake of that day’s obligatory meal. This is by rabbinic decree, with the reason (get this:) that it has the appearance of halachically “repairing” a broken, or unusable, vessel! The following lenient exceptions are to be considered: a) If the vessel is a drinking cup or water pitcher, I may dip it into the mikvah-pool in order to “fill it up” with water. If it just “happens” to get ‘toveled’ in the process, well, then, I just got lucky!!
b) The halacha of ‘toveling’ states that if the vessel is owned by a non-Jew (i.e. but kosher), it does not require ‘tevila’ (immersion) if a Jew uses it. Thus, if it is already Shabbos, and I am stuck without a ‘toveled’ dish that I really need, here is a halachic “loop-hole” you will love: give the vessel as a gift to a non-Jew, and then ask him if you can borrow it back to use until after Shabbos! Now it’s not your vessel, and you may use it without ‘tevila’! (Note: Are you wondering how it is permissible to give a gift on Shabbos, when we learned in a previous lesson that giving gifts is a form of business-practice, which is prohibited? The answer is that for the sake of oneg Shabbos, the rabbis did not prohibit gift-giving, as we pointed out in that lesson.)
c) Some dishes and utensils are customarily ‘toveled’ even though there is a halachic doubt whether they actually require it. (Ed: This was covered in the MBY series on ‘Tevilas Keilim’ some time ago. Archives, anyone?) If the vessels in question on Shabbos are of that class, and the aforementioned two leniencies do not apply, one may rely on another opinion which permits ‘tevilas keilim’ on Shabbos and Yom Tov! (Ed: In my experience, this leniency is rarely employed. Practically-speaking, one should make sure that ‘tevila’ of all vessels is done before Shabbos and Yom Tov begins!)