On Shabbos, may one place hot food on a plate that contains food or liquid?
Whenever one’s plate contains food on it, whether a solid or liquid, and one desires to place on it hot food, the question of Bishul [the prohibition of cooking food on Shabbos] arises. In certain circumstances, the hot food can cook the food that is on the plate. In other circumstances, there is no issue with doing so. This depends on the following matters:
- Is the hot food Yad Soledes [110 Fahrenheit]
- Is the hot food being poured from a Keli Rishon or a Keli Sheiyni and onwards?
- Is the hot food a Davar Gush [a hot solid food without gravy such as hot dry baked potatoes or Kugel or rice]?
- Is the food that is currently on one’s plate wet?
- Is the food currently on one’s plate already cooked?
- Is the food already on one’s plate hot or cold?
The law: All hot Yad Soledes [110 Fahrenheit] food that is being poured from a Keli Rishon has ability to cook other foods. This applies even if one uses a Leidal. If the food is being poured from a Keli Sheiyni, and is not a Davar Gush, then it does not have ability to cook other foods. Accordingly, if one pours the food content of the pot into a serving bowl, and then serves the food from the serving bowl, then if the food is not a Davar Gush [i.e. it does contain gravy], it cannot cook any food that is on one’s plate. If, however, one is serving hot food directly from a pot, which is a Keli Rishon, and placing it on the plate, then it can possibly cook any food or liquid that is already on one’s plate. If the food is a Davar Gush [solid hot food without gravy, such as Kugel or rice] then according to some Poskim it retains the status of a Keli Rishon even if it is being served from a Keli Sheiyni and onwards. Whether the Keli Rishon will cook the food on one’s plate is dependent on the type of food: If the food that is on the plate is a precooked [in liquid] dry solid, such as a piece of baked Shnitzel, then it is permitted to place Keli Rishon or Davar Gush food on it. If, however, the food on one’s plate is raw, or was never fully cooked [in liquid], or contains moisture that is not cooked, then placing Keli Rishon food on it poses a cooking prohibition. In such a case, one would need to use a new plate, or make sure to transfer the food to a Keli Sheiyni and only then serve from it. If the plate contains precooked liquid that has cooled down [but not congealed], then it is permitted from the letter of the law to pour liquid onto it from a Keli Rishon, but not a hot Davar Gush. Nonetheless, even in such a case it is best to be stringent.
Whenever one places hot Yad Soledes food onto one’s plate, he should make sure that the plate is clean from other uncooked foods, and is dry of any cold liquid or moisture. Alternatively, he is to make sure that the hot food is being poured from a Keli Sheiyni and is not a Davar Gush.
 Admur 318/9;11;24;29 s
 Igros Moshe 4/74 ; Minchas Yitzchak Likutei Teshuvos 29; Rav SZ”A in Minchas Shlomo 1/91; SSH”K 1 footnote 3
 Admur 318/19
 See Admur 451/28; Shach Y.D. 107/7; Taz Y.D. 92/30; M”B 318/87; Shabbos Kehalacha Vol. 1 p. 84-86;
 Admur 318/11; Michaber 318/4
 The Shach in Yorah Deah 105/8 rules that a Davar Gush has the ability to absorb taste into other foods even when in a Keli Sheiyni. So brings Magen Avraham 318/45, although the Tzemach Tzedek explains that the Magen Avraham himself does not hold of this opinion as the final Halacha. Nevertheless the Peri Megadim seems to rule to be stringent in this Lechatchilah and so rules the M”B 318/45 and 65 and 118 and Ketzos Hashulchan [124 footnote 15 and 39] and so appears to be the opinion of the Igros Moshe regarding practicality. The following Posakim rule leniently regarding a Davar Gush: Rama 94/7; Peri Megadim; Chovas Daas; Chasam Sofer; Aruch Hashulchan; Igros Moshe seems to be lenient from the letter of the law; Tzemach Tzedek Yoreh Deah 65, and so seems to be the opinion of Admur from the fact that in Halacha 31 he omit’s the novelty of the Magen Avraham which is that even in a Keli Sheiyni the roast may not have garlic placed on it, and Admur omit’s the Keli Sheiyni ruling.
 See Admur 318/12 that there is no Bishul Achar Bishul by a dry solid that was cooked. If however it was baked, the pouring onti it from a Keli Rishon is forbidden according to some opinions and so is the final ruling.
 Admur 318/19
 Tzemach Tzedek Mishnayos Shabbos 3, brought in Ketzos Hashulchan ibid footnote 31; Ketzos Hashulchan 124/12; Shevisas Hashabbos Hakdama Mivashel 19; Or Letziyon 2/30-10; Beis Meir brought in Biur Halacha “Vehu” that those that are lenient do not need to be protested; Igros Moshe 4/74 Bishul 18; Piskeiy Teshuvos 318/51
Background: See Admur 318/9 that the custom is to rule like the opinion that there is Bishul Achar Bishul by liquids; See the following Poskim that one may nevertheless always pour liquid of a Keli Rishon onto water, even if not cooked: Admur 318/20; Taz 318/18; Tosafus Pesachim 40b; Tur 318; Rashba, Ran and Rif on Shabbos 20a; Elya Raba Y.D. 68; Peri Megadim Yoreh Deah 68; Iglei Tal Ofeh 29; Tzemach Tzedek Mishnayos Shabbos 3/5, brought in Ketzos Hashulchan 124/12 footnote 31, and Tehila Ledavid 318, in understanding of Michaber/Admur. See Poskim who argue that one may not pour onto water from Keli Rishon: M”A 318/35; Tosafus Shabbos 42a that pouring on a minute amount of cold water is forbidden; Tzemach Tzedek Mishnayos Shabbos 3/5, brought in Ketzos Hashulchan 124/12 footnote 31; P”M 318 A”A 35; Gr”a; Chayeh Adam; Tehila Ledavid 318/28; M”B 318/78 and 85; Biur Halacha 318 ”Vehu Shelo”; Kaf Hachaim 318/130; Ketzos Hashulchan 124/11-12; Igros Moshe 1/93; 4/74; Minchas Yitzchak 9/30-31; Beir Moshe 6/110; ; Az Nidbaru 2/20; Teshuvos Vehanhagos 1/207; Piskeiy Teshuvos 318/51
 Tzemach Tzedek ibid; Poskim ibid
 As even if the ladle has remained a long time within the Keli Rishon, its pouring is defined as Iruiy Keli Rishon, which is permitted to be poured onto pre-cooked liquids, as explained above.