Opening Cans, Bottles and Boxes on Shabbos
The complicated question of opening cans and bottles on Shabbos has been debated at great length among contemporary poskim, and in the final analysis, there is no consensus as to the practical halachah. This Discussion, however, is to explain the halachic principles involved and to familiarize the reader with the main schools of thought regarding this complex subject.
There are six possible Biblical or Rabbinic prohibitions one may violate when opening bottles, cans or boxes on Shabbos. They are: 1) Kor’ea—Tearing; 2) Makeh b’patish—Completing the formation of a utensil; 3) Fashioning an opening, also a violation of Makeh b’patish; 4) Mochek—Erasing; 5) Mechatech—cutting or tearing to a specific size; 6) Soser—Destroying a utensil. In order to avoid violating any of these strict Shabbos prohibitions, it is highly advisable and strongly recommended that one open all bottles, containers and wrappings before Shabbos. Most people have a mental “checklist” of “things to do” on erev Shabbos, and opening boxes, bottles and bags of food and drinks should be on the list. Our Discussion, therefore, is aimed at those who forgot or failed to prepare properly for Shabbos.
Background and Basic Principles
Tosefta71 cites the following halachic decision which is quoted by all of the poskim:72 “It is permitted on Shabbos to rip the skin (in olden times, skins were used to seal barrels) off the top of a barrel (as long as there is no intention of creating a spout).” There is a great deal of controversy among the poskim as to why this is permitted, since it is prohibited to tear on Shabbos. Several explanations are given, but let us focus on the two basic approaches:
Chayei Adam73 explains that it is permitted because the ripping is done in a destructive manner. Since the cover is being ripped off and destroyed it is not considered Tearing and is permitted even mi-d’Rabbanan as long as it is being done for a Shabbos need. It is permitted, therefore, to rip off a salami wrapper, for example, since the wrapping is destroyed while it is being ripped. Thus, according to this approach, it is permitted to rip something on Shabbos only if the packaging will be destroyed as it is being opened.
Other poskim,74 however, explain the Tosefta differently. The reason it is permitted to rip the skin off the barrel (or the wrapper off a package, etc.) is that the wrapper is totally “subordinate” to its contents. Removing the wrapper is similar to removing a nutshell from a nut or the peel of a fruit—both of which are clearly permissible according to the Shulchan Aruch.75 As long as one is tearing for the sake of removing contents from a package, it is permissible to tear. According to this approach, it makes no difference if the package is destroyed in the process or not; even if the wrapper remains partially intact and is able to retain its contents, tearing is permitted. Still, even according to this view, it is forbidden to tear the packaging with the intent of reusing it at a later date, since in that case one is completing the formation of a utensil on Shabbos—Makeh b’patish.
This debate has ramifications for opening cans on Shabbos as well. According to Chazon Ish,76 when one opens a can one “completes the formation of a utensil.” Before the can was opened it was a “closed shell,” unusable as a utensil. After it is opened it becomes a container which can serve as a utensil. Since it was not destroyed in the process of being opened, it is forbidden to be opened on Shabbos. [In the view of yet other poskim,77 opening a can is not “completing the formation of a utensil” but rather “breaking an existing utensil” which is also prohibited on Shabbos.]
But the other poskim mentioned earlier do not consider opening a can as “completing the formation of a utensil” [nor do they consider opening a can as “breaking an existing utensil”]. In their view, since cans are generally discarded after their contents are removed, no usable utensil is created. Opening a can is merely like the peeling off of a “shell,” which is a permissible activity. Indeed, if the can is made from durable material which is meant to last and be reused in the future, then it is prohibited according to all poskim to open it on Shabbos, since none of the leniencies mentioned above apply.
71. Beitzah 3:9.
72. Beis Yosef, Magen Avraham and Mishnah Berurah 314:25. See also Shulchan Aruch ha-Rav 314:12 and Chayei Adam 29:4.
73. 29:4 (and in Zichru Toras Moshe, Kor’ea 3). This approach is followed also by Kitzur Shulchan Aruch 80:51, Kalkeles Hashabbos (Kor’ea) and Igros Moshe, O.C. 1:122, anaf 6. Chazon Ish O.C. 51:13; 61:2 also follows this approach but explains it differently; see Binyan Shabbos, vol. 1, pgs. 210-216 and 226-230 for a comprehensive review of this opinion.
74. Shevisas ha-Shabbos (Ma’aseh Choshev, pg. 12b); Chazon Yechezkel (hashmatos to Tosefta Shabbos); Rav S.Z. Auerbach (Shemiras Shabbos K’hilchasah 9, note 12 and Shulchan Shelomo 314:7-4). See also Igros Moshe, O.C. 1:122, anaf 9, who agrees, in principle, with this approach.
75. O.C. 314:8. See Binyan Shabbos, vol. 2, pg. 146, for a comprehensive review of this approach.
76. O.C. 51:11.
77. Tehillah l’Dovid 314:12.