The requirement to keep meat and dairy products separate necessitates that they be prepared with their own designated utensils. Accordingly, a kosher kitchen can be characterized by duplicates: two sets of pots, two sets of dishes, and sometimes even two ovens or two sinks.
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Utensils
Unless one is a vegetarian and totally excludes meat from their kitchen, a kosher kitchen must have two different sets of utensils, one for meat and poultry and the other for dairy foods. There must be separate, distinct sets of pots, pans, plates and silverware. One can buy labels or use a color coding system to help the kitchen stay organized.
Sinks
Ideally, it is best to have two kitchen sinks, one for meat and the other for dairy. If this is not feasible, and one uses one sink for both meat and dairy, dishes and utensils should be placed and washed on a rack, so as not to touch the sink.
- Separate racks are required for meat and dairy use.
- Care must be taken to make sure that the water not be allowed to rise to reach the level of the rack.
- Dishes cannot be soaked in a sink used for both dairy and meat.
Ovens
While nowadays many kosher homes use two ovens, this is impractical for many households to implement and there is of course room in halachah for cooking meat and milk in the same oven, though certain halachic limitations apply. There are many opinions among the authorities about this matter. The guidelines of the OU are as follows:
- An oven may be designated for either meat or milk use. Meat may be cooked in any manner in a meat oven, and the reverse is true for milk. To cook one type of food in an oven designated for the other type, one must perform a koshering process, as enumerated below.
- To cook a covered milk dish in a designated meat oven (or a covered meat dish in a designated milk oven), one must make sure that the oven is clean and then burn it out at 550 degrees Fahrenheit for 60 minutes (without the requirement of 24 hours downtime). One may then cook covered milk in the oven. So long as the cover remained on, the oven need not be kashered again afterwards.
- To cook uncovered milk in a designated meat oven (or uncovered meat in a designated milk oven), the oven must be cleaned and not used to cook meat for 24 hours. After 24 hours, one should burn it out at 550 degrees Fahrenheit for 60 minutes. At this point one may cook uncovered milk in the oven. The same process should be repeated before cooking meat in the oven again. (Alternatively, one can self-clean the oven, which is libun chamur, a thorough cleaning. Then they need not wait 24 hours.)
- One should not cook a covered dairy dish and covered meat dish in an oven at the same time. Even though both pans are covered, it is a common concern that one of the covers might open.
We are concerned about the interplay of the milk and the meat in two ways: through zeiah (steam) and reicha (by imparting odor).
It should be noted that until now our discussion has centered on cooking permissible foods in an oven that previously held a permissible designation. When considering cooking kosher food in a non-kosher oven, extra precautions are enacted.
For example, what would happen if you are staying in a motel and wish to use the oven to prepare your meals? The oven is dirty and you are not inclined to spend your vacation cleaning the oven. Based on the previous discussion, it follows that one may use a non-kosher oven simply by covering the food. The cover eliminates the circulating zeiah (steam) and therefore the non-kosher oven has no impact on the food.
However, because the oven is treif (unkosher), it is best to use a double wrap to insure against any zeiah leakage. It is precisely this logic that is utilized with kosher airline meals. The meals are double-wrapped and may therefore be heated in non-kosher ovens without compromising the kosher integrity of the product.
Tables
Dairy and meat may not be simultaneously present on the same table. This applies, though, only to a table upon which one eats; serving trays or serving tables are not subject to this rule (Shulchan Aruch, Yoreh Deah 88:1).
When transitioning from meat to dairy and from dairy to meat (as well as from dairy to poultry)—the table must be fully cleaned. The tablecloth and all dishes and cutlery must also be changed, of course.
Bread used with a meat meal may not be used with a dairy meal and vice versa.
How can one eat dairy or meat at a public table or bench (e.g., at a public park) when someone at the other end of the table may possibly be eating something that would constitute mixing dairy and meat?
The ban on having meat and dairy at the same table only pertains when the individuals eating together are friendly with one another, as there is a concern that they may share their meals and inadvertently end up eating meat and dairy together.
If they are strangers, or if they eat on placemats or place an object on the table to remind themselves that they should not share meals, they may eat at the same table.
So, too, if a religious Jew is eating dairy at a table where another individual is eating non-kosher meat, there is no need for a placemat or any other “reminder,” as there is no concern that the former will eat the non-kosher meat.
Resources:
- “Is Your Oven Kosher?“ by Rabbi Yaakov Luban
- “The Halachot of Waiting between Meals”