1. Question: [Sunday, 19^th Sivan, 5781]

Is it permitted for me to place an ice cube in my hot bowl of soup or hot cup of tea on Shabbos in order to cool it down enough so I can drink it?

Answer:

It is permitted to enter an ice cube on Shabbos into a cup of hot tea or a bowl of hot soup which is defined as a Keli Shelishi even though doing so causes it to melt.

Explanation: The prohibition against the passive melting of items on Shabbos only applies if the melted substances recognizable. If it is not recognizable after it is melted, and it is being melted in a passive form, then it is permitted to cause it to melt. Thus, the Poskim rule that it is permitted to enter ice into a cup of liquid in order to cool off the liquid, and it is clear from other rulings in the Poskim that this applies even if the liquid is hot, so long as it does not contain the cooking prohibition. Now, although technically it is permitted to enter water into a Keli Sheiyni, practically, aside for the fact that it is unclear if this applies likewise to ice cubes being that it does not mix right away with the liquid, even by a Keli Sheiyni, in addition, if the Klei Sheiyni liquid is very hot, as is often the case when one desires to cool it off with an ice cube, then it is to be treated like a Keli Rishon, and hence one should only enter an ice cube into hot liquids which are defined as a Keli Shelishi, which is anyways usually the case when one has a cup of tea which was made using a Keli Sheiyni, and one has a bowl of soup that was poured to from a Ladle.

Sources: Piskeiy Teshuvos 320:14 footnote  155;  SSH”K 1:90; See regarding entering ice cubes into wine to cool off: Admur 320:16; Michaber 320:9; Shabbos 51b; See regarding placing fat on top of rice for the melt [from which it is proven that even if the liquid is hot it is permitted]: Admur 318:26 and 28; M”A 318:40; Sefer Haterumah; Derisha 318:6; Elya Zuta 318:17; M”B 318:105 and 118; see regarding entering liquids into a Keli Sheiyni: Admur 318:22; 318:12; Michaber 318:12-13; Mishneh 41a;  See regarding the status of a very hot Keli Sheiyni: Admur 318:20; Michaber 318:11; Tur 318; M”A 318:34; Levushei Serud; Tzemach Tzedek Mishnayos 3:5; as explained in Ketzos Hashulchan 124 footnote 31; M”B 318:76; and 48; Chayeh Adam Shaar Mitzvas Haaretz 2:9; Rosh Yosef; Piskeiy Teshuvos 318:34; See regarding the status of a bowl of soup that was poured from a ladle: M”B 318:45; Minchas Yitzchak 5:127; Shabbos Kehalacha Vol. 1 p. 84-86