Answer by Rabbi Chaim Hillel Raskin, Moreh Hora’ah at Beis Horaa in Rechovot, Israel:
There are 3 possible melachos involved in opening a can:
Binyan, Stira: Chazal say that in some instances the melachos of building and destroying apply to vessels (1).
Some rishonim limit this to stable vessels made for long-term use, but not to flimsy containers (2). Others limit the prohibition to when the vessel is extremely large that it can contain 40 se’ah which is approximately 387 liter (3). Both opinions are quoted in halacha, and thus one may only break a small-sized flimsy vessel (4).
Makeh b’patish: Fashioning a “nice opening” to a vessel constitutes completing it, which is prohibited. This prohibition only stands when one intends to fashion a nice opening (i.e. for repeated use), otherwise it cannot be said to be “completing a vessel.”
Regarding a can, some poskim say that since it is sturdy and holds its contents for a long time, opening it is a prohibition of stira, destroying (5). However, many poskim suggest that since food cans are disposable and not intended for reuse they are considered “flimsy” and there is no destroying (6).
Additionally, since one has no intention of reusing it, if he doesn’t care to create a “nice opening” and there is no makeh b’patish either (7).
(Regarding a sturdy container, creating any opening is forbidden, as a concern that one will intend to create a nice opening.)
Since on occasion some people will reuse a can, some contemporary poskim insist that for the can to be truly considered deposable it is necessary empty out all its contents upon opening it. This demonstrates that the can is like a “wrapper” for the food, and not a vessel to be used (8).
Some acharonim (9) claim that the problem with opening is not the demolition of the can (stira), but the creation of a container (binyan). To circumvent this problem, some recommend puncturing a hole in the bottom of the can before opening the top. Thus he did not create a usable vessel (10).
Practically, one should endeavor to open all such cans before Shabbos. If not, one may open the can and spill out the contents right away. One who wishes to be scrupulous should puncture a hole in the bottom side before opening the can.
Sources:
1. ראה שבת קכב ע”ב ועירובין ל”ד ע”ב.
2. רא”ש עירובין פ”ד ס”ה.
3. ר”ן שבת ס”א ע”ב ד”ה שובר.
4. שוע”ר או”ח סי’ שי”ד ס”א.
5. וראה תהל”ד סי’ שי”ד ס”ק י”ב, וממלכת כהנים סי’ כ”ד שהכריעו לאסור
6. כף החיים סי’ שי”ד סקל”ח.
7. מנחת שלמה ח”ב סי’ ל”ב. ראה ספר להלכה ח”ב עמ’ רל”ד.
8. ראה קצוה”ש סי’ קי”ט בדה”ש סק”ז (וראה קצוה”ש שם סי”א).
9. ראה בארוכה ארחות שבת פי”ב הע’ ו’ שדן בזה באריכות.
10. ראה שש”כ פ”ט אות ג’ וראה מנח”י ח”ד סי’ פ”ב שרעיון זה מועיל גם לזה שמוכיח שיש לכלי דין מוסתקי.
Based on the article, I would tend to agree with you.
Amazing to see this can opener though, I didn’t know such a thing exists.
If it’s necessary to open, to simultaneously make a hole in the top and bottom of the can (I,e, with 2 can openers) so it’s not like forming a keili which can be re-used.
Why this illustration? Are flip top cans permitted to be opened that way on Shabbos?
Where is the alter rebbe’s opinion?
whats the makor
You can, you can’t . . .
rabbi a. osdaba said NO . you cant open cans
esp tuna cans
should not be used on shabbos
https://www.youtube.com/watch?v=B1VlfWvYeD8&safe=active
We hope CoL will send more articales like this in everyday practical Halachah . Thank you.
THIS PARTICULAR HALACHA OPENS UP A WHOLE CAN OF WORMS
Chatichah b’midah. Some say it’s a problem, because the hole is a specific size, while others say it’s alright, because you don’t really care what size it is.
Wouldn’t that be stira?! Please respond
To number 1, A soda Can already has the hole punched out, and it’s NEVER reused To number 2 Anyone who told you that, just comes from ignorance, as there is so much involved To number 3, 1 is not a question about opening a bottle, it’s about opening any package 2 not an issue, (source, the rebbe did it) To number 6, That might be an issue as well, as one is also not allowed to stab his sword into a barrel of wine, so on that note, it might be worse to make a second whole, I can… Read more »
What about orange juice containers with a ring?
Thank you for the Halacha. Happy to know I got it right!!
Please continue to post Shabbos Halachos
Finally! BH useful material! Thanks keep on coming!
Based on the article, I would think if you immediate pour the soda into a glass it would be OK. But IANAR!!!
This is great, thank you very much. I would like to see addressed the related issue of opening bottles: 1. A wine bottle where one has to cut the covering at the top in order to remove the cork. 2. A grape juice bottle with a plastic collar where the collar has perforations not on the writing — I heard someone say this is so you can open it on Shabbos without tearing the letters, I would like to hear whether it is still “cutting to size”. In both of the above cases it’s not customary to dump out the… Read more »
Thank you for this post! I learned in seminary that one cannot open cans on Shabbos, and then observed people who I believed to be careful about Halacha opening cans. Never pursued it, though. Thanks for the education.
How about a soda can?