Shiur #03: Defining the Melakha of Bishul (Part 2)

  • Harav Baruch Gigi
The Israel Koschitzky Virtual Beit Midrash

The Laws of Shabbat
Yeshivat Har Etzion

Shiur #03: Defining the Melakha of Bishul (Part 2)


By Rav Baruch Gigi

Translated by David Silverberg



            In the previous shiur, we inferred from the Rambam's formulation that softening metals constitutes a tolada (derivative) of mevashel, and is hence a Torah violation on Shabbat, only when it occurs through the medium of fire.  In this shiur we will attempt to clarify the concepts underlying this principle.


            We have already identified two different areas within the category of bishul: 1) preparing raw foods for consumption; 2) softening or hardening various non-food items.  Now, we will address the indispensable role of fire in each of these two kinds of bishul.


Fire as a Prerequisite in Cooking Foods


            The Rambam writes in his commentary to the Mishna (Shabbat, chapter 4), "it is only forbidden on Shabbat to heat or add heat with a derivative of fire."  Indeed, this is the straightforward understanding of the melakha of bishul, that it requires fire or a derivative thereof, and preparing a food item for consumption renders one liable for Shabbat violation only if he did so with fire.  (The term toledat ha-eish – or "derivative of fire" – refers to an item or substance that was itself heated through fire.)

            However, we find numerous discussions of this point in halakhic literature particularly as it applies to two instances – cooking through salting (maliach) and through pickling (kavush).  The term maliach refers to a food soaked in salt, such that over the course of time the sharpness of the salt softens the food, rendering it edible.  Halakha equates this process with standard cooking for purposes of beli'a – the absorption of forbidden taste.  Thus, if a non-kosher maliach food comes in contact with a permissible food item, we assume that the kosher item absorbed taste from the maliach, just as it would from a very hot food item.  This holds true as well for kavush – soaking a food in water or some other liquid for a twenty-four period is deemed halakhically equivalent to cooking, and we assume that taste transfers during this process, just as it does as a result of normal cooking.  The question thus arises whether these two processes of maliach and kavush are forbidden on Shabbat, given that they constitute a form of cooking.




            The Ramban (Avoda Zara 74b), amidst his discussion of the relationship between the cooking process and the transfer of taste, writes:


I find it very difficult: a bowl used for salting meat is forbidden, because salting is equivalent to boiling [and thus the bowl absorbed the blood from the meat – Chulin 111b], despite the fact that salting does not constitute cooking with respect to Shabbat, even if one needs it for a trip [and therefore salts the meat abundantly], as it says in Kelal Gadol [the seventh chapter of Shabbat – 75b].


The Ramban seeks to prove that transfer of taste can occur without a halakhically defined process of bishul, and in his view, this is precisely the situation during salting.  However, his proof from the fact that salting does not constitute a Shabbat violation seems somewhat difficult.  One could easily claim that salting indeed constitutes bishul, but nevertheless does not violate Shabbat because it does not entail the use of fire.  It would thus appear that the Ramban does not require the use of fire to violate the melakha of bishul on Shabbat, and he could therefore prove that salting is not equivalent to cooking from the fact that salting on Shabbat does not violate the melakha of bishul.


            The Ran (Avoda Zara, 38b in the Rif) takes issue with the Ramban, but appears to agree on this fundamental point: "I do not understand this, because there [in Masekhet Shabbat]… they said only that it [salting] does not constitute me'abed [tanning]… But we never find that it does not constitute bishul."  The Ran thus clearly accepted, in principle, the possibility of classifying salting under the category of bishul, despite the fact that it does not entail the use of fire.


            The Peri Chadash, however, understood that the Ramban and Ran indeed debate this fundamental point, with the Ramban denying the possibility of classifying salting under bishul, as it does not involve fire.  The Peri Chadash accepts this position he ascribes to the Ramban.  In my opinion, however, his reading of the Ramban's comments is very difficult, for as we explained, they imply to the contrary, that the involvement of fire is not a necessary component of bishul.


            Indeed, I found this argument advanced in a question posed to the Noda Bi-yehuda (Mahadura Tanina, Y.D. 43, s.v. ma she-sha'al):


I do not understand – according to this, what is the Ramban's proof?  For [perhaps] the absorption and expulsion of taste indeed depends on cooking, and the reason why one who salts on Shabbat does not violate mevashel is not because salting does not constitute cooking, but rather because even if he actually cooked he would be exempt [from liability] for forbidden activity on Shabbat, as it says in [Masekhet] Shabbat 39, that as far as Torah law is concerned, one is liable for mevashel with regard to Shabbat only if it occurs through a derivative of fire.


In his response, the Noda be-yehuda accepted this argument in principle, and endeavors to explain the Ramban's position:


With regard to Shabbat, there is no prohibition of bishul for salting.  This is because on Shabbat we derive [the melakhot] from the work performed in the Mishkan, and we therefore require a derivative of fire...  But this does not pose a difficulty for the Ramban: the Ramban maintains that afiya [baking] proves the point – it was not done in the Mishkan, and nevertheless, since bishul was done in the Mishkan with the dyes, afiya is included under bishul.  The reason why one is exempt [if he cooks] with the hot water from the springs of Tiberias is not because it does not constitute bishul since it does not resemble the activities performed in the Mishkan.  Rather, the reason is that it is not customary to cook with it – something that is not a derivative of fire.  The Rambam therefore ruled that even with regard to [the prohibition of] meat and milk, which certainly is not derived from the Mishkan, nevertheless, cooking [meat and milk] with it [water from hot springs] is forbidden but one is not subject to malkot [flogging] for it, since it is not the normal manner of cooking.  He similarly ruled with regard to Shabbat, in Hilkhot Shabbat 9:3, that one who cooks with hot water from the springs of Tiberias is exempt from punishment.  But his main reason is his uncertainty if it is customary to cook with it.  But salting – had it constituted "cooking," then one would even be liable [for salting on Shabbat], since it is customary to salt [meat] if one needs it for a trip.


It thus appears that the Noda Be-yehuda himself maintains that bishul requires a derivative of fire[1], but he understood the Ramban as holding one liable for any manner of cooking that conforms to normal cooking procedures, regardless of whether it occurred through fire.


            The Minchat Chinukh (Mosakh Ha-shabbat, 11) posits a novel theory, that salt indeed constitutes a derivative of fire: "But salt, [which one produces by] cooking water and thereby the salt is made, and it is not as salty before the cooking as after the cooking, and it is thus a derivative of fire, since it is cooked with fire – it can perhaps be said to ‘cook'."  Clearly, this is a rather far-fetched contention.  One might explain the Ramban's position far more simply, by suggesting that any preparation of food for consumption, irrespective of the medium employed, constitutes bishul.  This is indeed the approach taken by the Avnei Neizer (Y.D. 88):


But salting – this is, of course, customary, to salt foods, and the taste of salted foods and that of cooked foods differ from one another; salted foods have a taste that cooked foods do not have, and thus one who wishes to eat a salted food necessarily does so without [making use of] a derivative of fire – [therefore,] if you would say that salting has the power of bishul, one should be liable [for cooking through salting on Shabbat].


The Yerei'im, by contrast, writes explicitly that salting does not render one liable for cooking on Shabbat (vol. 2, p. 139a, me'abed): "And although it says [in Chulin 111b] that salting amounts to boiling, one is not liable for salting on [Shabbat], since it is not derived from fire."




            The Rambam writes (Hilkhot Shabbat 22:10): "One may salt an egg, but [salting] radishes and the like is forbidden, because it resembles pickling, and pickling is forbidden because it is like cooking[2].  One may dip radishes and the like in salt and eat."  This ruling has generated considerable interest among the Acharonim.  The Rambam here forbids salting a radish because of this process's resemblance to pickling.  Now if pickling itself is forbidden only mi-de-rabbanan (by force of rabbinic enactment), then a prohibition against salting radishes by virtue of its resemblance to pickling should amount to a gezeira le-gzeira – a rabbinic prohibition legislated as a safeguard against another rabbinic prohibition, which we generally do not find.  Seemingly, then, the Rambam considered pickling a Torah violation of Shabbat.  On the other hand, as can easily be seen in the Rambam's arrangement of his presentation of Hilkhot Shabbat, from chapter 22 and onward he addresses the shevutim – the Shabbat prohibitions enacted by the Rabbis.  And in chapter 9, where he discusses the Torah prohibitions included under the category of bishul, he makes no mention whatsoever of kavush as a Torah prohibition of bishul.  We should also note that when he does mention this prohibition, in chapter 22, he writes that pickling is "like cooking," but not actually a form of cooking.  This, too, would seem to indicate the pickling constitutes a rabbinic, rather than Biblical, prohibition on Shabbat.


            The Acharonim disagree in explaining the Rambam's position.  The Kereiti U-pleiti and Mor U-ketzi'a understood that the Rambam approached kavush as a Torah prohibition, but the Chokhmat Adam and Sedei Chemed argued, claiming that it was legislated by Chazal.  The Noda Be-yehuda (Mahadura Tanina, Y.D. 60) writes:


Regarding his difficulty with what I wrote, that the Rambam did not bring the law of kavush, in light of what he wrote in chapter 22 of Hilkhot Shabbat, "pickling is forbidden because it is like cooking" – I have difficulty with his difficulty.  Why did he not take note of how I wrote very precisely that throughout the Rambam's Hilkhot Ma'akhalot Asurot I did not find this law of kavush?  I was very careful [to point out that I referred specifically] to the issue of forbidden foods; what does Shabbat have to do with this?  On Shabbat, if one prepares a completely inedible item so that it is now edible, he is liable for cooking, and just as cooking prepares it for consumption, so does this [pickling] prepare it.  And the kulias ha-ispanin [Spanish colias fish] and mali'ach yashan [a type of salted fish], which one is liable if he rinses [in hot water], the Rambam likewise wrote in chapter 9 of Hilkhot Shabbat that their rinsing is their final stage of cooking.


Clearly, then, the Noda Bi-yehuda believed that one is liable on Shabbat for any food preparation, regardless of whether it involves fire or a derivative thereof.[3]  According to this position, we might explain that the Rambam brings this law in chapter 22 because salting a radish is forbidden only mi-de-rabbanan, as it resembles the process of pickling, but pickling itself indeed constitutes a Torah violation.


Softening and Hardening Non-food Items


            The Rambam's comments concerning this issue are more straightforward: "In sum, both burning a solid substance WITH FIRE and solidifying a soft substance – one is thereby liable for [the melakha of] cooking" (Hilkhot Shabbat 9:6).  Here, the Rambam very clearly requires the use of fire.  Of course, this is easily understood according to the Acharonim who apply this demand to cooking foods, as well; in their view, all instances of bishul require the involvement of fire.  The other view, which claimed that one can violate bishul by cooking foods through other media, might explain that non-food items can be softened or hardened only through fire.  If so, then essentially we have two types of toladot for the principal melakha of bishul.  The principal melakha is the preparation of raw food for consumption and softening it through fire, and the derivatives of this av melakha come in two forms: preparing foods for consumption through any means, and softening or hardening non-food items through fire.  The first type of tolada resembles the av in terms of its purpose – preparation for eating – whereas the second resembles the av in terms of the actual process – softening through fire.


The Final Halakha


            As we have seen, some Rishonim, including the Yerei'im and the Rambam in his commentary to the Mishna, write explicitly that the melakha of bishul requires the use of fire or a derivative of fire.  Given the Rambam's explicit remarks to this effect in his commentary to the Mishna, I am inclined to explain his comments regarding kavush as referring to a rabbinically legislated prohibition.[4]  By contrast, it appears from the comments of the Ramban and Ran that we may indeed classify other means of food preparation as bishul, the question being only with regard to salting, whether it has the capacity to "cook."  The Acharonim, as mentioned, are is disagreement on the matter.  In practice, the general consensus among the poskim restricts the Torah prohibition of bishul to processes involving fire and its derivatives, reducing salting and pickling to the status of rabbinic prohibitions.  In fact, many authorities claim that salting and pickling do not involve the category of bishul at all, and are rather rabbinically ordained prohibitions under the melakha of me'abed (tanning; this melakha does not, on the level of Torah law, apply to salting foods, so these processes must be forbidden only mi-de-rabbanan).


            The Shulchan Arukh (O.C. 321) cites the Rambam's formulation that kavush "is like cooking," to which the Mishna Berura (15) comments, "This reason is cited from the Rambam.  Rashi gives the reason that foods harden as a result of the salt, and it is thus a tikun [preparation] similar to me'abed."  In a different passage there, the Mishna Berura adds:


A vegetable pickled for preservation – since salt water is added as a preservative, it resembles the processing of leather, which is preserved by the salt.  And even though we maintain that the Torah prohibition of me'abed does not apply to foods, it is nevertheless forbidden by force of rabbinic enactment, as the poskim write.


The Strength of the Fire


            In light of our conclusion that the involvement of fire is a prerequisite for the melakha of bishul, we must address the issue of the minimum strength required to render a flame capable of performing bishul.  It is clear that one can violate bishul by soaking food in hot water from a keli rishon (the original utensil in which the water was boiled) or by placing it near a flame or hot kettle, since Halakha equates derivatives of fire with fire itself for purposes of this melakha.[5]  But the poskim argue regarding melting wax (or butter, according to the view that butter is subject to bishul – see previous shiur) with heat at a level below the point of yad soledet bo (at which one's hand would instinctively recoil on contact).  This question generally does not arise regarding foods and liquids, since, quite obviously, foods and liquids cannot reach the point where they are considered "cooked" (ke-ma'akhal ben drusai for foods; yad soledet bo for liquids) without exposure to this level of heat.  Still, this question presents itself according to the view in the Gemara (Shabbat 40b) that warming oil violates bishul: would one be liable for warming oil with a heat source that does not generate heat at the level of yad soledet bo?


            The Shevitat Ha-Shabbat (bishul section, 13, in Be'er Rechovot 13) writes very clearly that one is liable for melting butter even with heat below the point of yad soledet bo.  This position appears as well in the Peri Megadim (Eishel Avraham, 318:37).  However, Shemirat Shabbat Ke-hilkhata (chapter 1, note 173) writes the following in the name of Rav Shlomo Zalman Auerbach zt"l:


It is possible that anything that does not require heat at the level of yad soledet bo to soften – one is not liable for softening the solid substance, such as, for example, melting a piece of sugar.  The aforementioned [comments of] the Peri Megadim refer to a case where the softened item will not reach the level of yad soledet bo.  But if yad soledet bo is not necessary for the purpose of softening, it is not considered cooking at all.


Rav Shlomo Zalman thus maintained that only heat at a level of yad soledet bo can qualify as "fire" for purposes of bishul, and he attempted to reread the Peri Megadim's comments to accommodate this theory. 


            I believe that this issue might hinge on a debate among the Rishonim concerning the Gemara's discussion of warming oil.  The Gemara (Shabbat 40b) tells:


Rabbi Yitzchak Bar Avdimi said: I once followed Rebbi [Rabbi Yehuda Ha-nasi] into the bathhouse, and I asked to place an oil flask in the bath for him.  He said to me, "Take [some water from the bath] in a second utensil and place [the flask in that utensil]."  We learn three [halakhot] from this.  We learn that bishul applies to oil; we learn that a keli sheni [utensil into which hot liquid was poured from its initial utensil] does not have the capacity to cook; and we learn that warming it [oil] is equivalent to cooking it.


The Rishonim argue as to whether the final clause in this passage should read – as we cited it, based on Rashi's view – "warming it is equivalent to cooking it," or, as Rabbenu Chananel's text reads, "warming it is NOT equivalent to cooking it."  Rashi explains his version of the text as follows: "Warming it in a place capable of cooking is equivalent to cooking it, for all he [Rabbi Yitzchak] asked to do was to warm it, and he [Rebbi] forbade it."  It appears from Rashi's comments that although warming oil constitutes bishul, this holds true only "in a place capable of cooking it."  Therefore, even though a keli sheni is capable of warming the oil, nevertheless, since it does not have the capacity to effectuate bishul, one may use it to warm oil.


            The Rashba challenged this version of the text and Rashi's explanation:


But in any event, their version of the text does not read well.  For if it were true, there should be no difference between a [keli] rishon and [keli] sheni; it should be forbidden in any situation where it [the oil] cooks, for they distinguished between keli rishon and keli sheni only because one can effectuate cooking and the other cannot effectuate cooking.


According to the Rashba, once we consider warming oil halakhically equivalent to cooking, then one violates the prohibition even by cooking it in a keli sheni.  He therefore prefers Rabbenu Chananel's version of the text, that "warming it is not equivalent to cooking it," and for this reason one may warm oil in a keli sheni.[6]  It thus emerges that Rashi and the Rashba argue with regard to the possibility of effectuating bishul with a level of heat generally incapable of cooking, in those rare instances – such as oil, according to one view – where an item can be considered cooked without reaching the point of yad soledet bo.  This debate very likely underlies the dispute among the Acharonim as to whether one may melt wax, butter and the like with a level of heat below yad soledet bo.


            One may, however, distinguish between the two contexts, by contending that a temperature below yad soledet bo does not qualify as "heat" at all.  Thus, even the Rashba, who accepts the possibility of effectuating bishul with the heat of a keli sheni, would permit melting wax and butter with a heat source that does not reach the level of yad soledet bo.


Halakhic Conclusions from this Shiur


  1. The Torah prohibition of bishul applies only to cooking with fire or a derivative thereof.
  2. The Rabbis forbade salting food on Shabbat.
  3. Pickling foods is forbidden on Shabbat; the poskim debate the issue of whether this constitutes a Torah prohibition, or was legislated by Chazal.
  4. The poskim debate whether one may melt wax, butter and sugar cubes through heat at a level below yad soledet bo.




  1. This would resolve the seeming contradiction noted by later Acharonim between this responsum of the Noda Be-yehuda and his comments elsewhere (Mahadura Tanina, O.C. 23).  The support he expresses here for the possibility of considering salting a violation of bishul does not reflect his personal view, and was rather stated to explain the Ramban's position.  See, however, his comments cited below concerning the issue of kavush.
  2. The Rambam's position that pickling amounts to bishul runs counter to the implication of the Gemara in Shabbat 108b, as explained by the Rishonim, that the prohibition stems from the resemblance between pickling and tanning.  Seemingly, kavush has no connection at all to bishul, since it does not involve the use of fire.
  3. See above, note 1.  These comments of the Noda Be-yehuda call into question our earlier claim, that he would not consider salting a violation of bishul.  We might suggest distinguishing between salting and pickling.  The Noda Be-yehuda perhaps felt that salting cannot constitute bishul since practically it does not cook, but rather triggers the process of absorption.  Pickling, however, actually cooks the given food, and may thus violate bishul despite the absence of fire.  We should also note that his proof from the kolias and mali'ach ha-yashan is hardly compelling, since in that case one rinses them with hot water – a toledat ha-eish (derivative of fire; meaning, it had been heated through fire).  These issues of course require more comprehensive discussion in a separate context.
  4. The Rambam here follows his general theory that all shevutim (Shabbat prohibitions enacted by Chazal) are anchored in specific melakhot.  Here, too, he sees salting and pickling vegetables within the framework of rabbinic prohibitions involving food preparation, an adjunct to the melakha of bishul.  We will encounter other examples of this tendency of the Rambam over the course of this series.
  5. The Mishna in Masekhet Shabbat (145b) speaks of ha-ba ba-chamin – foods cooked in hot water, and an earlier Mishna (38b) forbids cooking an egg by placing it next to a hot kettle, which the Gemara (39a) considers a Torah violation.  In a later shiur we will iy"H discuss these issues in much greater detail.
  6. The Ritva, by contrast, claimed that both versions of the text yield the same result, interpreting Rashi in accordance with Rabbenu Chananel's approach.  He writes:


The prevalent text, which is also the text of Rabbenu Chananel z"l, reads, "warming it is not equivalent to cooking it."  Meaning, for this reason he allowed him [to warm the oil] in a keli sheni, which has the capacity only to warm.  But Rashi z"l has a text that reads, "warming it is equivalent to cooking it."  This does not mean to say that it constitutes actual bishul, for if so, then it should be forbidden even in a keli sheni.  Rather, this is what it means: where it can be cooked, even warming it is considered cooking it, and is forbidden.  This is how Rashi explained.  Both versions of the text are thus one and the same.