Parsha Chabura Mishpatim:Bishul Basar B'Chalav

This week’s shiur was about the issur of cooking milk and meat together. Besides the issur of eating and deriving benefit from a milk and meat mixture, there is also a prohibition of cooking milk and meat together.

The Chakirah

There are two ways one can understand this issur. Is the issur the "ma’aseh bishul", in other words it is assur to cook the milk together with the meat or maybe we can say that the issur is the creating of a milk/meat mixture ("yetziras ha’ta’aroves"). It should be noted that even if the issur is the creation of this mixture, it is only assur if it is done thru cooking. The cooking process is a t'nai ( a condition) of the issur.

Nafka Mina
1) Is it assur to recook a meat and milk mixture. One is not allowed to let meat sit in milk for more than 24 hours. This is called "kavush" and is a form of cooking. However, it is only assur m’d’rabanan. The Sha’arei Dura writes that one is not allowed to cook the mixture aftrewards.. Rabbi Akiva Eiger (Yoreh Deia Siman 87) infers from here that if the meat/milk mixture was previously cooked it would not be assur to recook it. This is because "ain bishul acher bishul". Once something is cooked it can not be recooked. However, we pasken on Shabbos that by liquids there is bishul acher bishul. If so, maybe by basar b’chalav it should be assur to cook a basar b’chalav liquid mixture. How come Rabbi Akiva Eiger doesn’t differentiate between solids or liquids?

We can say that it depends on our chakirah. If the issur bishul is the act of cooking, so maybe it should be assur. But if the issur is to create a mixture of meat and milk, so in our case the milk/meat mixture is already created so there would be no issur to re-cook it.

2) Can I take a piece of cooked meat and a piece of cooked milk and cook them together. The Gilyon Maharsha (Siman 87) says it would be assur. Maybe it depends on our chakirah. If the issur is the ma’aseh bishul so ain bishul acher bishul and it is muttar. But if the issur is creating the mixture so I am now creating a mixture and it should be assur.

3) Can I perform a chemistry experiment which requires cooking meat and milk. In Pininei HaRav , Rav Schachter brings down a ma’aseh with Rav Moshe Soloveitchik where he was asked this question. Rav Moshe Soloveitchik answered that the issur of bishul basar b'chalav is in order that you shouldn’t eat it. In our case you aren’t going to eat it so it is muttar. Clearly, if you hold like the first tzad of the chakirah (that the issur is the ma’aseh bishul) then it should be assur.
4) The Chsam Sofer (YD siman 92) has a shailah if you can use basar b’chalav to light the chanukah candles. He says since the issur is the ma’aseh bishul it is assur. According to our second tzad, it should be muttar since you are not creating a mixture- the oil/wax will be burned up.