Shiur #23: Using an Urn

  • Rav Yosef Zvi Rimon



By Rav Yosef Zvi Rimon


.We join in mourning the passing of Mrs. Rita (Sara Rivka) Rimon z"l, beloved mother of Rav Yosef Zvi Rimon
.HaMakom yenakhem etkhem betokh she'ar avelei Tzion veYerushalayim



XXII) Using an Urn



What should one be concerned about in using an electric urn on Shabbat?


Does such a device require kashrut certification?


Forbidden Urns


At the beginning of our analysis of the laws of bishul we dealt with a solar heater, which heats water for washing.  Now we will deal with an electric urn, which is generally used to heat water for drinking.  Some of these devices are very advanced, so that opening a tap turns on a light or activates a pump.  Obviously, these urns cannot be used on Shabbat.  Similarly, one cannot remove hot water from a water dispenser (commonly called a “cooler,” but in fact containing both hot and cold water), since this causes new water to come in and boil.  (In some devices, before dispensing the water itself, a mechanism quickly heats the water, right before it comes out.)[1]


However, when it comes to most basic urns, these problems do not exist.  Therefore, apparently, there should not be a problem with using a standard device.  However, we must analyze a number of points before coming to any conclusions about removing water from an electric urn. 


Before Boiling


First of all, we must note that one may not take water out of the urn before it boils, because if the tap will remain open, the water inside will never reach the boiling point (because it will come out), so by closing the tap, the person causes the remaining water to boil.[2]  Aside from this, removing water causes the quantity of water to be reduced inside the urn, so that the water remaining will boil more quickly.[3]




When the water in the urn is already boiling,[4] there is no problem to remove it, but we must discuss the use of an urn that has a thermostat that activates the heating element when the water is not hot enough.  In this case, removing the water may likely cause the water in the urn to cool faster (the less water there is, the more easily it cools, and cold air comes in place of the water that had been in the urn), so that the thermostat causes the heating element to be activated earlier.  It may even be that that removing the water will lead to the immediate activation of the heating element.  (Moreover, if the heating element is now in operation, removing the water will cause it to shut off earlier, since the quantity of water has been reduced and the urn will finish heating the water sooner). 


The Minchat Yitzchak (Vol. V, ch. 91) is stringent about this; however, Rav S.Z. Auerbach rules leniently (cited in Maor Ha-Shabbat, Vol. I, pp. 509-510):


What he wrote about an electric urn with a thermostat, wondering if it is permitted to remove water from them on Shabbat, in my view this is also allowed, because he does not [try to time his opening of] the water at the time that it will be activated by the thermostat.  It is not clear whether this activity will lead it to activate; furthermore, this is only gerama (causation), and it is not a pesik reisha (an inevitable result), and therefore it appears that it should be permitted. 


According to Rav S.Z. Auerbach, the person who removes the water has no intention of activating the heating element, nor is it inevitable; moreover, this is only gerama.  Therefore, this should be allowed. 


Some, however have questioned Rav Auerbach’s position: while it is true that removing the water will not immediately result in the activation of the heating element, it will cause the heating element to activate earlier (if only by a half-second), and this is in the category of pesik reisha.  However, from the continuation of Rav Auerbach’s words, it appears that even when we are talking about a pesik reisha, one may be lenient, since the melakha here is executed through gerama, and this is not the regular way to operate the urn.[5]


Minchat Yitzchak


Another problem relates to an urn that has a gauge — a connected pipe on the outside that shows the quantity of water in the urn.  Since the water in the gauge is relatively far away from the heating element, it does not reach the boiling point at the same time as the water in the urn, and we should be concerned that when one removes the water from the urn, the water in the gauge will be mixed with the water in the urn and boil.  The Minchat Yitzchak (Vol. X, ch. 28) writes: 


As for an electric urn that has a glass pipe showing the quantity of water, our master allows using it… but our master does not discuss at all the water in the glass pipe, which does not boil when the water inside boils and only gets a bit hot, and in any case certainly it is not fully cooked to the point of bubbling.  Behold when we remove water from the urn, from this [action] the water in the pipe enters the urn and boils there, and this is cooking on Shabbat…


According to what we discussed above from the Eglei Tal’s omissions, even though it is already yad soledet bo (scalding), in any case, as long as it is not bubbling, it is still not bishul by Torah law, and according to this, in our case in which the water enters the urn, if it boils afterwards until the point at which it bubbles, one violates the prohibition of bishul. 


Thus, in his view, assuming that the water in the gauge does not reach the level of full boiling, when water is removed from the urn, this water mixes with the water in the urn and heats up, so that one may violate the melakha biblically!




However, it appears that one may be lenient about this.  First of all, we are talking about a small quantity of the water, one that the person is not interested in and does not care about, so this is an inevitable but unwanted result, a pesik reisha de-lo neicha leih.  Similarly, in the standard urn, this is mere gerama, because removing water brings this about only indirectly when the water in the gauge enters the urn, and we have already seen that one may be lenient about the gerama of a pesik reisha.  (However, we should note that in an electric thermos, this is not gerama, because water is removed from this thermos by way of the gauge, so that taking out water automatically causes boiling water to enter the gauge.) 


Moreover, many Rishonim and Acharonim (Me’iri, 40b, s.v. Meicham; Chiddushim Ha-myuchasim La-Ran ad loc., s.v. Shemen; Chazon Ish 37:27; Shevitat Ha-Shabbat, Introduction to the Melakha of Mevashel, 18; et al.) believe that once water has become yad soledet bo, there is no prohibition of bishul violated by heating it further.  Generally, when the water in the urn reaches the boiling point, the water in the gauge is above 50ºC, so one may consider it to be at the level of yad soledet bo;[6] from here on, there would be no problem of bishul.


However, in an electric thermos, the gauge is in fact the pipe by which one takes out the water, and sometimes the water in it is colder.  On the other hand, in a thermos such as this, one may easily dismiss the concern — one may remove half a cup of water from the thermos after it has boiled the water (before Shabbat), and thus one may replace the water in the gauge with boiling water from the thermos.  Practically, this action can help also with a regular urn, because the gauge is connected to the pipe by which the water comes out, and removing the water causes the water in the urn to mix with the water in the gauge. 


However, even if the water in the gauge does reach boiling, we should consider another problem: it may be that over Shabbat, the water in the gauge will cool and fall below the temperature of yad soledet bo.  According to the Rema, there is no problem in this, because the water in the gauge is still somewhat warm, and we apply the rule of ein bishul achar bishul (there is no prohibition to cook a previously cooked item) even to a liquid, as long as it is somewhat warm (see our earlier shiur on this topic).  However, according to the Shulchan Arukh, there is a prohibition of bishul for a liquid at the moment that it is no longer yad soledet bo (see there).  Apparently, according to this, Sefardim would have to be stringent, since the water in the gauge will come down over the course of Shabbat, falling below yad soledet bo, and removing water from the urn will cause it to boil. 


Rav Ovadya’s Leniency


Practically, according to some Sefardic authorities, one may add a number of justifications for leniency.  This is what Rav Ovadya Yosef writes in Yechaveh Da’at (Vol. VI, ch. 21):


This belongs in the category of davar she-eino mitkavein (unintentional results), because in opening the tap of the urn there is no intent to bring water from the pipe into the urn; it is a pesik reisha.  In any case, presumably one does not care about the water that comes in through the pipe, because it is a very minimal amount, and it ends up boiling in the boiling water [already] in the urn.  It is known that the view of the Arukh is that a pesik reisha de-lo neicha leih is totally permitted, even rabbinically…


Now, this matter is clear, because at the time of boiling the water in the urn before Shabbat, the water in the pipe reaches at least yad soledet bo temperatures, but over the course of the day of Shabbat, its heat is reduced, and it is possible that at times it falls below yad soledet bo temperatures, but this is not clear at all.  In any case, since many halakhic authorities believe that ein bishul achar bishul even for liquids…


This remains true even though our master rules in Shulchan Arukh in accordance with Rashi and the Rosh and the Tur and Rabbeinu Yona to be stringent about Torah prohibitions, assuming that bishul achar bishul applies to liquids.  Nevertheless, in our case, it is a rabbinical prohibition, because of the pesik reisha de-lo neicha leih.  Even according to the words of those who forbid, this is only on a rabbinical level; because of this, it would be a rabbinical doubt, and one may be lenient…


Another consideration is that the opening of the tap, which causes water to enter from the pipe into the urn, is not defined as an action, but rather mere gerama


In conclusion, one may use an urn that has a glass pipe attached to it to indicate the height of the water in the urn.  Even though, at the time of opening the tap, water from the pipe, which is not very hot, comes into the boiling hot water in the urn, one need not be stringent about this at all. 


In his view, it is not clear that the water in the gauge ever goes below yad soledet bo.  Nevertheless, even if this does happen, one need not worry about cooking this water, since this is both a case of both pesik reisha de-lo neicha leih and gerama.  Aside from this, one may enlist the views of most Rishonim who believe that there is no bishul achar bishul for any liquid, even if it cools all the way.  Many other authorities are also lenient: Az Nidberu (Vol. IX, ch. 14), Or Le-Tziyon (Vol. II, ch. 30, note 10), et al.

Therefore, it appears that halakhically one may be lenient and use even an urn that has a gauge (one who is stringent may remove half a cup of water after it boils, before Shabbat begins).


Adding Water


However, using an urn may involve another problem.  The Yerushalmi (3:3) forbids using an urn which is not gerufa, since if the water runs out, the urn will be ruined, and there is a concern that one may add water in order to avert this.  This principal is mentioned by the Mishna Berura (318:118):


If our cooking vessel, which is known as a samovar (urn), is heated before Shabbat, one may not take water from it on Shabbat, even though the coals have not been swept from it.  [This is what is written by the Tosefet Yerushalayim… in the name of the Yerushalmi, which says that one cannot drink on Shabbat from an urn which has not been swept; the reason is that it is made of components, and one may become worried that the component will be consumed and therefore add water.]


According to this, apparently our urns should present a problem, as one may add water to prevent their being ruined (see Shemirat Shabbat Ke-hilkhata 1:40).  However, in our time, one may be lenient practically for two reasons: first of all, the tap is not installed at the precise bottom of the urn, and naturally even after the water is no longer coming out of the tap, water remains in the urn.  Secondly, in most urns today there is a safety mechanism which disconnects the electricity if the water runs out, and naturally a person is not worried about the urn being ruined.  (It is understood, that if there is very little water, so that water does not come out unless one tilts the urn, one should be careful not to remove all of the water, so as not to cause the immediate shutting off of the urn.)


Different Kashrut Certifications for Urns


In fact, today one can buy urns with the certification of the Zomet Institute or of the Technological Institute, who certify that the urn is permissible for use on Shabbat.  The standard certification of the Zomet Institute is given to an urn on which one has no direct influence upon the heating element by removing water (but at most an indirect effect), and the water in the gauge reaches at the time of boiling or immediately afterwards 50ºC (though it does not necessarily stay that way later).[7]  There is also a mehadrin certification, which is given to an urn that has no thermostat at all (but only a heating element that operates constantly or according to a predetermined time) or has a thermostat that one may deactivate; the water in the gauge of such an urn does not go below 50ºC.  However, one who is lenient to use a standard urn without any certification has upon whom to rely.  (Nevertheless, the punctilious will remove half a cup of water after it boils, before Shabbat; this is appropriate to do particularly for an electric thermos).


As for institutional urns, which are hooked up to a water supply so that water enters the urn over the course of Shabbat, the matter is more complex, and there is a need to receive halakhic authorization in order to use it on Shabbat.




In conclusion, most domestic urns may be used without concern (as long as the water reaches boiling before Shabbat), and there are those who are punctilious to buy an urn with certification.  As for institutional urns, these require the certification of the Zomet Institute, the Technological Institute and the like. 


Translated by Rav Yoseif Bloch 

[1]      Another question, which we will not deal with at this time, is whether one may remove cold water from this device.

[2]      Indeed, we should analyze whether this action is biblically forbidden, because a person does not bring the water to a place where it will be boiled; rather, the water is already there, and he only stops it from leaving.  This is similar to the case of the confiner, one who prevents another from leaving water or fire and causes his death. For criminal purposes, the Gemara (Sanhedrin 76b) considers him a murderer, but it is not clear what the law would be for the melakhot of Shabbat.  In any case, it makes senses that there is a prohibition on the rabbinical level at least.

[3]      See the Minchat Yitzchak (Vol. III, ch. 137); he discusses whether one is considered to be causing bishul by doing this.

[4]      As we have seen in previous shiurim, the water needs to be at least at the level of yad soledet bo, so that there will not be any problem of bishul relating to it, and for this issue, Rav Feinstein believes that one should be stringent until it reaches above 71ºC.

[5]      This is what appears from his words below: he allows opening the door of a house that has a heating system activated by thermostat, even though this will cause the hastening of activating the furnace, even if the activation of the oven involves an act of kindling on a biblical level.

This is also what arises from the long responsa of Rav S.Z. Auerbach about a refrigerator (Minchat Shelomo, Vol. I, 10:6): it is possible to be lenient in a case of pesik reisha performed by gerama, even if a biblical prohibition is involved.  Granted, we do not allow one to do melakha on Shabbat ab initio by way of gerama except in a case of loss (see Rema 434:22); nevertheless, we are not stringent about this unless one intends to execute an act by way of gerama, but when we are talking about an davar she-eino mitkavein, one need not be stringent about gerama, even when we are talking about a pesik reisha.  This is what arises from the ruling of Rav S.Z. Auerbach, concerning the melakha of zoreia, in the context of a sink which empties out on top of a pile of seeds; see there.

In a case in which one removes water while the heating element is active, there is more reason to be lenient, since in this case, the concern is that the heating element will shut off earlier, and this concern is only rabbinical, because a melakha she-einah tzerikha le-gufah is biblically permissible (though rabbinically banned).  A melakha she-einah tzerikha le-gufah is a melakha that one performs without any interest in its essence, but for the sake of an incidental result.  When dealing with the gerama of a pesik reisha of a rabbinical ban, there is good reason to be lenient.  However, according to the view of the Chazon Ish, breaking an electrical circuit involves the biblical melakha of destroying, but since the thermostat is of course turning the heating element on and off constantly, and the person only has a small influence on the frequency of this occurrence, this would not be building or destroying, even according to the view of the Chazon Ish (Minchat Shelomo loc. cit.) 

[6]      However, as we previously stated, the view of Rav Feinstein is that when the measure of yad soledet bo is for lenient purposes, one must be stringent for 71ºC.  Nevertheless, common sense tells us that the hand shrinks from water as warm as 50ºC, and there are those who rule like this halakhically, as we mentioned there.  In any case, for the issue of water in the gauge, this temperature may be sufficient, since there are a number of additional reasons to be lenient about this.

[7] For some urns, the kashrut certification is dependent on the condition that one must remove a bit of water after it boils, before Shabbat.  One may find specific details about the different models of urns at the Zomet Institute website.  On this website, one may find the details of the urns, and which are certified as standard kosher or mehadrin.  (Thus, for example, if a certain urn has the problem that the water in the gauge falls below yad soledet bo after it boils, so that Ashkenazim would consider it mehadrin, even though officially it would receive only the standard kosher certification.)