Opening Cans on Shabbat by Rabbi Chaim Jachter


This week we will discuss the permissibility of opening cans on Shabbat.  We will trace the development of the debate from the Gemara and Rishonim to the Shulchan Aruch and its commentaries, and through twentieth century Halachic authorities.

Gemara and Rishonim – Shabbat 146a and Eruvin 34b

The Mishna (Shabbat 146a) states that one may break open a barrel in order to retrieve the figs contained in the barrel, if one does not intend to create a functional opening for the barrel.  A problem with this rule is that it seems to be a destructive act (Soter), which should be forbidden (on a rabbinic level) on Shabbat.  Rashi (as interpreted by the Ran to the Rif Shabbat 61b s.v. Shover Adam) explains that since one destroys the barrel to obtain Shabbat needs, the rabbinical prohibition to destroy is waived.  This Gemara indicates that one may open a container to gain access to the food inside.

On the other hand, the Gemara (Eruvin 34b) indicates that one may not break open an object in order to gain access to the contents.  This Gemara teaches that one may not break a shed to obtain the food inside it.  Accordingly, the Gemara in Eruvin appears to contradict the Gemara in Shabbat.

There are two main schools of thought in the Rishonim regarding how to resolve this apparent contradiction.  The Ran (ibid.) and other Rishonim argue that Shabbat 146a represents the conventional case.  Eruvin 34b constitutes the exception, as it is speaking of breaking an exceptionally large vessel.  The policy of Chazal to suspend the rabbinic prohibition against breaking items if the breaking is done for Shabbat needs, applies only to breaking items normally used for food storage.  However, Chazal never waived their prohibition in the case of breaking a very large item such as a shack.

Tosafot (Shabbat 146a s.v. Shover), on the other hand, argue that Eruvin 34b represents the conventional case.  Shabbat 146a constitutes the exceptional case because it is speaking of breaking a makeshift and flimsy vessel (a Mustiki).  Tosafot argue that Chazal prohibited opening a conventional vessel because of concern that one create a viable opening.  Chazal are not concerned that he may make a viable opening when one opens a Mustiki.  Since a Mustiki is a poor quality item, it is not worth investing the effort in order to make a functional opening. 

The Rambam (Hilchot Shabbat 23:2) seems to agree with the Ran, as he does not limit permission to break open a vessel containing food to a Mustiki.  The Rambam and Ran do not believe that Chazal were concerned lest one create a viable opening.  The Rosh (Shabbat 22:6), however, follows the approach of Tosafot.   

Shulchan Aruch, its Commentaries, and Nineteenth Century Codes

The Shulchan Aruch (314:1) rules in accordance with Tosafot and the Rosh.  This is somewhat surprising since the Shulchan Aruch here rules in accordance with the Ashkenazic Rishonim and rejects the approach of the Sefardic Rishonim.  The Biur Hagra (O.C.314:1 s.v. Sheeinah Machzeket), though, rules in accordance with the Ran and the Rambam.  The Mishna Berurah (314:7) mentions the ruling of the Vilna Gaon, but does not regard the Vilna Gaon’s opinion as normative. 

This decision of the Shulchan Aruch troubles the Aruch Hashulchan (O.C. 314:7-8).  The Aruch Hashulchan wonders why the Shulchan Aruch chose to reject the opinion of such a significant number of Rishonim on this issue, which involve only a Rabbinic prohibition.  The Aruch Hashulchan concludes that one should not rebuke those that follow the opinion of the lenient Rishonim and the Vilna Gaon in this context. 

Cans – Four Approaches

The issue of opening cans has been vigorously debated for many decades.  Four basic approaches have emerged.  The Tehillah Ledavid (314:12) believes that cans constitute sturdy vessels, which are forbidden (on a rabbinic level) to open, lest he fashion a proper opening.  

On the other hand, some Poskim (Kaf Hachaim 314:38; Rav Shlomo Zalman Auerbach, cited in Shmirat Shabbat Kehilchata 9: footnote 10; Rav Ovadia Yosef, Teshuvot Yechave Daat 2:42;) regard cans as a Mustiki, since cans are customarily discarded after use.  We stress that even these authorities prohibit opening a can if one intends to use the can for storage after removing its contents.  Moreover, these authorities urge accommodating the stricter opinion and opening cans before Shabbat.  Rav Yosef Adler reports that Rav Yosef Dov Soloveitchik subscribes to the lenient approach.

The Chazon Ish (O.C. 51:11) adopts a very interesting position regarding cans.  He believes that a sealed can is not the Halachic equivalent of a barrel, which is forbidden to open only on a rabbinic level.  He argues that a can, unlike a barrel, does not have the Halachic status of a vessel (Kli).  The Chazon Ish therefore asserts that when one opens a can he “transforms a [functionless] sealed item into a functional Kli.”  Hence, the Chazon Ish believes that opening a sealed can constitutes a violation of the biblical prohibition of Binyan (building) on Shabbat.  Rav Shlomo Zalman Auerbach (Shmirat Shabbat Kehilchata 9:footnote 10) notes, however, that one could argue that Binyan occurs when sealing the cans in the factory.  It seems counterintuitive to Rav Averbach that sealing the cans constitutes an act of Soter when one’s intention is to facilitate shipment and long-term integrity of the food contents. 

Rav Moshe Feinstein (Teshuvot Igrot Moshe O.C. 1:122) wrote a lengthy responsum on this topic.  It is interesting to note that Rav Moshe wrote this Teshuva in 1935 when the Soviet police placed him under house arrest because of his service as a community Rabbi.  Ironically, this Teshuva explores this issue in great depth, perhaps because of the extra time Rav Moshe had available to concentrate on his writing because of the limitation the Soviet authorities put on his activities outside the home (note Shemot 1:12, which tells us that the more they try to hurt us, the more we flourish). 

Rav Moshe writes that it is theoretically permissible to open cans that people customarily discard after emptying their contents.  He believes that opening these cans is analogous to cracking open a nut or peeling a banana (see Shulchan Aruch O.C.314:8).  Rav Moshe argues that even Tosafot, Rosh, and Shulchan Aruch would permit opening this type of can, since there is no concern for fashioning an opening.  However, Rav Moshe writes that it is forbidden to open those cans that some people use after emptying its contents.  Regarding these cans there is concern that one will create a functional opening.  Rav Moshe also believes that when one intends to use a can after emptying its food contents, he creates a Kli.  Rav Moshe believes that the can is not a Kli because people intend to use it only once.  Only when one intends to reuse a can does it attain the status of a Kli. 

These assertions also have ramifications for the Halachot pertaining to Tevilat Keilim.  Rav Moshe (Teshuvot Igrot Moshe Yoreh Deah 3:23) rules that Tevilat Keilim is not required for disposable items, since they do not enjoy the status of a Kli.  Similarly, one who wishes to fill a Snapple bottle with water need not immerse the glass in a Mikvah before drinking the water based on these principles that Rav Moshe outlines.  The Snapple bottle is disposable and is not regarded as a Kli.  When a Jew decides to use the empty Snapple bottle as a water container, he has upgraded the bottle to a Kli status.  It is considered as if the Jew created the Kli and therefore the bottle does not require Tevilah according to Rav Feinstein (Teshuvot Igrot Moshe Yoreh Deah 2:40; but others disagree, see Teshuvot Seridei Eish 2: Y.D. 75).

Rav Moshe writes that in practice one should not even open cans that people customarily discard.  He expresses concern that people who are not learned will be unable to grasp the distinction between cans that we may open and those we may not.  He cites Shabbat 139, where the Gemara forbids certain permissible activities for communities where the people are not scholars, as a precedent for this approach.  Rav Moshe notes the lack of Torah scholarship and the prevalence of Chillul Shabbat in our generation.  Hence, he refrains from issuing a lenient ruling that he feels will ultimately lead to Chillul Shabbat. 

My student Mashiach Farzanfar notes that Rav Moshe’s concern is particularly relevant today when people fill empty cans with garbage in order to save space in the garbage can.  Since one intends to use the can as a receptacle for garbage after emptying its food contents, it seems that he violates a biblical prohibition of creating a Kli when opening a can.

Nevertheless, Rav Moshe permits asking a non-Jew to open a can that people customarily discard after use in case of great need.  It is for this reason, Rav Moshe writes (Teshuvot Igrot Moshe O.C. 5:21:24), that such cans are not Muktzeh. 

We should note that Rav Moshe Feinstein (Teshuvot Igrot Moshe O.C. 3:76) and Rav Moshe Soloveitchik (cited in Nefesh Harav p.189) forbade Yom Tov Sheini burials in America due to concern that this practice will lead to violations of Hilchot Yom Tov in this country due to the low level of Torah scholarship among the broader Jewish community.  Chassidim continue to practice burial on Yom Tov Sheini in this country.


There is a rich debate whether one may open cans on Shabbat.  Almost all poskim agree that the best policy is to survey the situation at home on Erev Shabbat and open any cans that one might need on Shabbat.  Next week we will discuss the issues of opening various containers on Shabbat.

Fashioning Openings to Utensils on Shabbat by Rabbi Chaim Jachter

Religious Infertility by Rabbi Chaim Jachter