- Question: [Monday, 13th Iyar 5781]
I accidentally baked dairy cheese Borakes [thinking they were Pareve potato filled] in my meat oven at the same time that I baked meat. What is the law of my food and oven?
If the meat and dairy products which cooked in the oven simultaneously were not covered and hence allowed for their vapors to mix, then everything is forbidden, and the oven must be cleaned and Koshered. If both foods were covered in a way that vapor cannot escape from the foods, and there was no meat residue in the oven at the time, then everything remains permitted. If only one of the foods was covered and the other was uncovered, then the covered food becomes forbidden, and it is disputed if also the uncovered food becomes forbidden and practically one is to be stringent to prohibit everything and the oven must be Koshered.
Explanation: Although the Talmud and Poskim differentiate between different types of ovens regarding if one cooked a permitted and forbidden food together in it, practically this only applied in ovens of medieval times where the only issue was the smell released from the food and the debate was regarding whether we say that “Reicha Milsa Hi.” However, by today’s ovens which are much smaller and insulated, the issue is much more severe as it is an issue of vapor, and hence unless vapor was not released due to the foods being covered, then everything is forbidden.
Sources: See regarding the issue of vapor: Michaber and Rama Y.D. 92:8; 108:1; See regarding the law by today’s ovens: Igros Moshe Y.D. 1:40 in length for the Zeiah concerns in our ovens and that they have the same status as a pan placed over two uncovered foods, brought in Rama 108:1; Maharsham 3:208; Minchas Yitzchak 5:20; Chelkas Yaakov 2:136; Kinyan Torah 1:24; Badei Hashulchan 92:166; Darkei Halacha p. 242
Sources regarding of only one food was covered: See Admur 447:10 and Michaber 108:1 that it suffices for even one of the foods to be covered, however, that is regarding Reicha. However, regarding Zeiah, so long as the vapor of one of the foods hits the other food, it is forbidden, and thus both foods must be covered. Accordingly, if either the meat or milk food is uncovered, then seemingly both foods are forbidden as it is similar to the case of Rama 92:8 where the uncovered milk pot prohibits the even covered meat pot, as the vapor travels towards it. Similarly here, the vapor travels from the meat to the covered milk, and prohibits the covered Heter. Furthermore, even the uncovered food becomes forbidden as perhaps the vapor of the uncovered travels to the covered food, becomes prohibited, and then returns back to the uncovered food and prohibits it. [See Peri Toar 92:16; P”M 92 M.Z. 29; Degul Mirivava 92 regarding that the dairy uncovered pot also becomes forbidden even if the meat pot was covered. However, some Poskim are lenient to permit the uncovered food: See Peri Haaretz 2:14; Erech Hashulchan 92:14; Implication of Michaber and Rama ibid and Toras Chatas 56:8; Brought in Kaf Hachaim 92:93; The Kaf Hachaim ibid concludes that one who is lenient does not lose out.] This especially applies according to Admur 451:41 [and Levush 93] who learns that the vapor prohibits due to the law of Nitzuk Chibur, and hence it is as if one poured meat onto a Ben Yomo dairy pot, in which the Rama 95:3 rules it is forbidden. [This is unlike the P”M ibid and O.C. 441 A.A. 44 and Yad Yehuda 92:52 who learns that the prohibition of Zeiah is due to Mamashus falling back inside.] Vetzaruch Iyun from Kaf Hachaim 108:32 who explains that the Zeiah case which prohibits is if both the Heter and Issur are uncovered.