By Rabbi Chaim Hillel Raskin, Moreh Hora’ah of Beis Horaa Rechovot, Israel
Chazal forbade crushing ice to produce water on Shabbos (1). There are several reasons offered by the rishonim:
1. One is forming a new entity (borei) (2).
2. The liquid is nolad (3)
3. It is similar to squeezing juice from fruit on Shabbos – mashkin shezavu (4).
If the ice melts on its own, even if one caused it to melt by taking it out of the freezer, one did not actively produce the liquid, though the resulting liquid is new. Thus according to the first and third opinions the liquid is permissible, however according to the second it is prohibited (5). The Alter Rebbe advises being stringent if it is not too difficult.
If the melting liquid that came as result of crushing ice is mixed with other liquid there is no concern of mashkin shezavu since fruits are squeezed alone, but one has nonetheless actively created something new. (6) The Alter Rebbe rules that this is prohibited.
If one allows the ice to melt into liquid on its own, all opinions would permit it, since one is not actively causing it to melt and it is melting into another liquid.
When adding ice cubes to a beverage, one should not pour the beverage over ice cubes or stir the ice to melt it, since one is actively causing it to melt,7 but rather add the ice to a cup or pitcher with liquid.
Likewise, one may add juice concentrate to water on Shabbos, as long as one does not stir it to disintegrate faster.
1. גמ’ שבת נ”א ע”ב.
2. רש”י שם ד”ה כדי, וראה חי’ הרשב”א שם.
3. ספר התרומה סי’ רלה. וראה שוע”ר סי’ שי”ח סכ”ה שהוא סניף ממלאכת בורא (הלשון נולד הוא בהשאלה להמחשה בלבד).
4. ע”פ רמב”ם הלכות שבת פכ”א הי”ג.
5. שוע”ר סי’ שי”ח סכ”ה.
6. שוע”ר סי’ ש”כ סי”ט.
7. שוע”ר סי’ ש”כ ס”כ עיי”ש.
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