Lash (Part 1) Definition of the Melakha

  • Rav Yosef Zvi Rimon



By Rav Yosef Zvi Rimon


Shiur #19:

Lash, Part I



May one pour water over flour without mixing?  Is it permissible to wash one's hands over sand or dirt?


I) Defining the Melakha


The melakha of lash (kneading; the process is known as lisha) pertains to an action that has an opposite objective to that of the melakha of tochen (grinding), as well as the melakhot of dash (threshing), zoreh (winnowing), borer (selecting) and merakked (sifting).  The other melakhot listed here are performed in order to separate substances. Dash, zoreh, borer and merakked separate between the wheat (or the flour) and various types of refuse, while tochen reduces the wheat kernels to grains of flour. Lisha, on the other hand, is a binding melakha. In the process of kneading, one fuses together separate, tiny parts and turns them into one unit. (Note that the definition of the melakha is a subject of debate as we shall see below.)


The melakha of lash is not limited to foods, e.g., the preparation of dough from flour and water; rather, it applies to other substances as well — for example, kneading water and dirt is forbidden by the Torah, as a subcategory of lash (Rambam 8:16, according to the Gemara, 18a).


It is not only lisha per se that is banned by the Torah; rolling the dough (with a rolling pin) is also forbidden by Torah law, since it is part of the greater process of the melakha.  (Yerushalmi 7:2).


Before delving into the details of the melakha, certain terms need to be defined.  A substance may or not be bar gibbul (kneadable), and the mass formed may be of two consistencies: belila ava (a thick mixture) or belila rakka (literally, a soft mixture, i.e., a thin one).  Several questions need to be raised regarding these terms: Does lisha apply to that which is not bar gibbul?  What is the difference between belila ava and belila rakka, practically and halakhically? What is prohibited by Torah law, what is prohibited by rabbinic law, and what is permissible?  We will see the various views and the rulings as we continue.


The melakha of lash is an extremely complex one.  We will try to first grasp its principles, and after that we will try to examine the practical halakhic ramifications.


II) Mixing Flour and Water Without Kneading


The Gemara (155b) cites a dispute among the Mishnaic authorities as to the question of when one can become liable for lash:


If one puts in the flour and another puts in the water, the latter is liable, according to Rabbi.  Rabbi Yosei bar Yehuda says: "One is not liable without kneading."


Thus, according to Rabbi (Yehuda Ha-nasi), combining water and flour is enough to make one liable for lash, while according to Rabbi Yosei bar Yehuda, one cannot become liable until one actually kneads them together until they form dough.


The Root of the Argument


What is the basis of this dispute? It may be that this argument stems from divergent understandings of the nature of the melakha of lisha. According to Rabbi, the essence of the melakha is the very blending of two different substances, while according to Rabbi Yosei bar Yehuda, the essence of the melakha is the fact that two substances stick to each other and agglomerate.  This is the Eglei Tal’s explanation of the dispute (Lash, 9:13). However, this explanation raises certain difficulties in the explanation of the melakha.[1] 


Alternatively, it may be that according to all views, the essence of the melakha of lash is that the two substances adhere and form one mass, but according to Rabbi, one may be liable for any significant act which hastens this result, even if it has not yet been achieved.  This principle emerges from the melakha of bishul (cooking), in which one may be liable for acts of partial cooking (anything above the minimal level of edibility).[2]  On the other hand, according to Rabbi Yosei bar Yehuda, one may be liable only for an action which brings about the ultimate result of a single mass.[3]


Halakhic Ruling


The Rishonim and the Acharonim argue as to which view is followed in this dispute.


The Rif (67b), the Rambam (21:34) and the Rosh (24:3) rule in accordance with the view of Rabbi Yosei bar Yehuda (since the anonymous mishna on 155b follows his view), that there is a liability only for producing dough.


On the other hand, the Yere'im (Ch. 274, 133b), the Teruma (Ch. 220), the Semag (Prohibition 65, lash) and the Semak (Ch. 280) rule in accordance with the view of Rabbi (because of the general Talmudic principle that the halakha follows Rabbi Yehuda Ha-nasi when he has one opponent), so that one is liable for the very act of putting water into flour.


The Shulchan Arukh (321:16, 324:3) cites the lenient view (that of Rabbi Yosei bar Yehuda) without any comment, and after that he introduces the stringent view (that of Rabbi) with the words "There are those who say."  The general principle is that the Shulchan Arukh endorses the view which he includes without attribution; this would suggest that the Shulchan Arukh rules leniently, that there is no Torah prohibition in putting water into flour without kneading it.  And indeed this is the ruling of the Maamar Mordekhai (321:13), Rav Ovadya Yosef (Livyat Chen 67).  And the Menuchat Ahava (Vol. II, Ch. 9, end n. 9).


On the other hand, the Rema (321:16) rules in accordance with the view of Rabbi, that putting water into flour is forbidden by the Torah.  The Ben Ish Chai (Year 2, Mishpatim 18) indicates that Sefardim must also rule stringently in accordance with this view, and this is the ruling of the Kaf Ha-chayim (324:14) and the view of Rav Mordekhai Eliyahu. 


We should note that Rabbi Yosei bar Yehuda, who believes that there is no Torah prohibition of pouring water on flour, would concede that there is a rabbinic prohibition, because he says, "One is not liable without kneading" — but he does not say that it is permissible.  This is noted by the Ritva (155b) and the Me'iri (18a) and cited by the Beit Yosef (Ch. 324, s.v. Aval).[4] 


Thus, putting water into flour without lisha is forbidden for both Ashkenazim and Sefardim; however, while for Ashkenazim it is a Torah prohibition, for Sefardim it appears that it is prohibited rabbinically.  (Nevertheless, even Ashkenazim rely on the lenient view in certain cases, as we will see below.)


This dispute has various practical ramifications, as we will see below.


III) Pouring Water on Sand or Dirt




Children are allowed to play in a sandbox on Shabbat because it is designed for play and it is therefore not muktzeh (308:38).  However, they are not allowed to play with sand on the beach or with dirt at a construction site, etc. because it is muktzeh on Shabbat, in the classic sense — i.e., it cannot be used because it lacks a recognized Shabbat use (Mishna Berura ibid. 144).


As we have seen, there is a prohibition (whether Torah-based or rabbinic in nature) to pour water on flour, and the same applies to sand.  Therefore, while children are allowed to play in a sandbox, it is forbidden for them to pour water over it, even if they do not actively knead it by hand.




This issue comes up frequently for people on hikes, in the army, or eating in the sukka — may one wash one's hands on the "floor" when it is dirt or sand?  Watering the ground may fall under the melakhot of plowing or sowing at times, but when the ground in question has nothing planted in it and is not designated for cultivation, these melakhot are not a concern. However, one must investigate if there is a reason to prohibit this act because of lash. As we have seen, pouring water on sand (just like pouring it on flour) is forbidden according to everyone: according to Rabbi, by Torah law; and according to Rabbi Yosei bar Yehuda, by rabbinical law.


This question also arises in situations when one must urinate in the field.  The Yere'im (Ch. 274, 133b) indicates that one may not urinate anywhere where there may be a problem of lisha (i.e., where the ground is not hard).  However, the Acharonim debate this, as the Mishna Berura cites (321:57):


The Magen Avraham writes, "It appears to me that it is forbidden to urinate upon mud, because of kneading..." 


The same would apply to loose dirt and sand.  While it is true that one has no intention of lisha, it is an inevitable result.  As for a spittoon or a basin sitting on fine or coarse sand, it requires further study if this should be permitted or prohibited, because it might be an inevitable result which one has no interest in [which is sometimes allowed]. 


However, I have found that in the book Beit Meir that he allows it for this reason, in a case of need, to urinate even upon mud. 


It appears that one may rely on this [lenient view] when the mud does not belong to the one urinating, for in such a case one certainly has no interest in its lisha.   


Thus, the Magen Avraham forbids urinating on mud because of lisha, and the Mishna Berura adds that according to this one may not urinate on loose dirt or sand. On the other hand, the Beit Meir allows this because the person does not intend to perform lisha, and the halakha essentially follows Rabbi Yosei bar Yehuda, who holds that pouring water on mud and the like is only prohibited rabbinically.  Thus, the case is one of an undesired, inevitable result of a rabbinical prohibition, which is allowed in a case of need.


The Mishna Berura rules that one may rely on the Beit Meir in a case of need as long as the dirt is someone else's, because then we say that the one urinating certainly does not "desire" to change the consistency of another's dirt.   


Therefore, one should be careful not to urinate on sand or on loose dirt, but when there is a great need (such as there is no other convenient place), one may be lenient.  In any case, one may urinate on hard ground.


What about washing hands?  Here too, it is best to look for a place in which the water will not be spilled on sand or soft dirt, but in a place of need, one may be lenient.  However, there is a simpler solution.  Rav S.Z.  Auerbach allows using a sink which empties out among plants, as long as the water goes through a pipe first.  This renders the act one of causation, and one may be lenient about this if one does not intend to water the plants.  In a similar way, if one washes one’s hands over metal or stone, even if the water flows down to sand or soft dirt, this is permitted, since this is considered causation and one has no interest in wetting the ground.  (In a case where one is interested in watering the ground, the act would be forbidden.)


Thus, it is permissible to wash one's hands over stone, even if the water will flow afterward into sand or soil with plants in them.  Even if the stone has some dirt on it, there is no problem, since the mixture formed will be primarily liquid, so there is no true blending.  Similarly, it is permissible to wash one's hands into a sink which empties into sand or plants, as long as one does not own them, does not benefit from the irrigation and is not interested in it.




In conclusion, it is forbidden to pour water on sand, and therefore children who are playing in a sandbox may not pour water in it.  To wash one's hands, or urinate, on the ground, one should look for a place free of sand or loose dirt.  However, in a case of need, one may be lenient (especially when one needs to relieve oneself), and there is also room for leniency if the water will first flow onto stone or metal and only after that reach the ground.

Translated by Rav Yoseif Bloch



[1]     This approach can be questioned based on the fact that everyone agrees that there is no liability for making a belila rakka, as we shall se below. Consequently, Rabbi does not rule that one is liable for the very act of mixing. One might wish to suggest that everyone agrees that mixing flour and water is considered lisha, but according to Rabbi Yosei bar Yehuda, since the person only pours the water on the flour and the blending happens on its own, this would be considered causation, while one is only liable if one does an act of lisha by hand.  However, beyond the fact that this argument is difficult, the Gemara in Zevachim (94b) states that one who puts water into flax-seed is liable according to everyone, because the water and the flax-seed adhere to each other and form one mass. This would indicate that even according to Rabbi Yosei bar Yehuda one may be liable for the melakha of lash without a manual act of lisha.

[2]     There may be a practical ramification between the two understandings of Rabbi in a case in which water is put in flour before Shabbat — may this mixture be kneaded on Shabbat?  According to the second understanding, it is clear that this is forbidden by the Torah, because the lisha and the mixing of water and flour are the essence of the melakha.  On the other hand, according to the first reading, it may be that this is permissible, since the essence of the melakha is the very mixing of the flour and the water, and once they have been blended, the melakha of lash is no longer applicable. However, it may be that even according to this understanding, kneading this mass must be forbidden on Shabbat, since one strengthens and improves the commingling of the flour and the water. The Bei'ur Halakha (321:14, s.v. Ein Megabbelin) writes that when one puts in the water before Shabbat, Rabbi concedes that kneading on Shabbat is forbidden by the Torah.  He cites as a proof-text the aforementioned passage in the Yerushalmi, who says that even one who rolls the dough is liable.  The implication is that once the lisha has already been done, anyone who beautifies and improves upon it is liable. This is connected to the question of lisha achar lisha, which we will deal with later.

[3]     In the view of Rabbi Yosei bar Yehuda, we must ask: does the melakha of lisha relate only to the action of kneading, which blends the flour and the water and fuses them into one body?  If so, pouring the water into the flour is not an integral part of lisha.  Alternatively, does the melakha of lisha relate to the entire process, from the instant that the flour and water come into contact until they become one mass of dough?  The practical ramification of this would be in a case in which one person pours in the water and another person kneads the mixture and creates dough — is the kneader liable, or is neither of them liable, since neither carries out the process in its entirety?  Similarly, there is a ramification in a case in which the water is put in the flour before Shabbat and the actual kneading is done on Shabbat. See the Eglei Tal's analysis (Lash, 2) of these issues.

[4]     It may be that the question of whether Rabbi Yosei bar Yehuda believes there is a rabbinic prohibition of adding water to flour depends on a question which we raised earlier. If he believes that the melakha of lisha relates to the entire process, but one only becomes liable upon its completion, there adding the water would be prohibited, because it initiates the act of lisha. However, if the action of the lisha is the kneading on its own, it may be that putting in water is not forbidden even rabbinically, since there is no lisha involved in it. (However, it may be that even according to this approach there is a rabbinic prohibition to add water to flour, since this is an act which allows lisha to occur, even if it is not considered part of the lisha.)