What is the halacha regarding using an oven for milchig and then pareve / flieshig and then pareve? Is it different for chassidim / sefaradim / litaim? I know that by us we DO NOT do that, and a friend told me that there is no base to this behavior.
Answer:
It is not true to say that there is no basis for this behavior, though in principle it is true that one can make use of the same oven for meaty and dairy foods — provided the foods are dry.
The problem of using a meaty over for dairy foods is generally limited to foods that are moist, and therefore give off steam: If both meaty and dairy steam are absorbed by the walls of the oven, the oven becomes treif.
Even for dry foods, as an additional precaution some advise that different racks be used for meat and dairy, or that the rack be covered with new aluminum foil before the dairy dish is placed in the oven.
Because is it hard to determine which food is “dry,” and because any time we discern steam rising from the dish it is considered “moist,” it is generally preferable to have two ovens, one for meaty and one for dairy.
If the same oven is used for meaty and (moist) milky foods, the foods should covered up well, and a better option is to actually perform a basic kashering procedure (cleaning and turning on at high temp.) between use for dairy and meaty dishes — though some rule that this procedure should not be used on a regular basis (Chelkas Yaakov 2:136).
In principle is it permitted to use the same oven for meaty and dairy foods, provided the foods are dry.
The problem of using a meaty over for dairy foods is generally limited to foods that are moist, and therefore give off steam: If both meaty and dairy steam are absorbed by the walls of the oven, the oven becomes treif.
Even for dry foods, as an additional precaution some prefer that different racks be used for meat and dairy, or that the rack be covered with new aluminum foil before the dairy dish is placed in the oven.
Because is it hard to determine which food is “dry,” and because any time we discern steam rising from the dish it is considered “moist,” it is generally preferable to have two ovens, one for meaty and one for dairy.
If the same oven is used for meaty and (moist) milky foods, the foods should covered up well, and a better option is to actually perform a basic kashering procedure (cleaning and turning on at high temp.) between use for dairy and meaty dishes — though some rule that this procedure should not be used on a regular basis (Chelkas Yaakov 2:136).
I do not know of differences in this matter between different communities.
Best wishes.
Concerning covered foods, see Shulchan Aruch, Yoreh De’ah 108:1; Ksav Sofer 54; Igros Moshe Yoreh De’ah 3:10; concerning dry foods, see Igros Moshe Yoreh De’ah 1:40 (and 1:59, concerning baking a challah) based on Pischei Teshuvah 92:6.
