Halakhot of Kashrut Part 3 - Kitchen Appliances

  • Rav Yosef Zvi Rimon
Laws of Kashrut: Kitchen Appliances
Based on a shiur by Rav Yossi Zvi Rimon
Translated by David Silverberg
     In this shiur we will deal with the halakhot related to appliances found in virtually every modern kitchen, including the halakhic problems that arise regarding these appliances and the possible solutions.
     Most people have a single stovetop in their home.  At first glance, it seems very difficult to understand why it is halakhically acceptable to use a stovetop for both meat and dairy pots.  And, the fact is, for Pesach everyone either kashers their stovetops or switches the grates.  Why, then, do people use stovetops for both meat and dairy pots?
     For purposes of clarification, we will point out that when we speak of "stovetops," we refer to the grates upon which we place the pots.  The problem arises when these grates absorb food particles from the meat pots, for example.  If thereafter one places on the same grate a dairy pot, the pot will absorb from the grate, such that, presumably, the pot should become non-kosher.
     The Mishna Berura writes (451:34), "We may assume that even if it spilled, it has already been burnt and disappeared, since it is constantly on the fire."  The grates are always on top of a hot flame, such that they actually undergo the kashering process constantly.  Therefore, no meat particles are absorbed by the dairy pot.  The Mishna Berura then adds a different reason: "For in truth, when two pots touch each other, the absorbed particles are not transferred from one to the other."  Two dry objects do not transfer taste unless there is liquid in between them.  But this reasoning holds true only if, indeed, no liquid had been on the stovetop for the last twenty-four hours.  But when the liquid in a meat pot, for example, overflowed onto the stovetop, and a dairy pot was then placed on the stovetop and it, too, overflowed, the process of absorption of taste indeed occurs, and the pot, according to this reason of the Mishna Berura, becomes non-kosher.
     It is therefore preferable to designate grates on the stovetop for meat and dairy pots, so as to avoid these problems.  And in any event, if a meat pot overflows, it is forbidden to place a dairy pot on the grate immediately thereafter.  One must first clean the area and ensure that all remnants of the meat food have been cleared away or burned.
     The biggest problem that arises regarding stovetops is splattering.  Splattering occurs on stovetops very frequently, particularly during frying, when a drop of oil can very easily fly from the meat frying pan onto a dairy pot sitting next to it.
     We will not present here a thorough treatment of this issue, but rather address one fundamental point.  The Shulchan Arukh rules (Y.D. 92:5): "If a drop of milk falls parallel to the food, it requires only sixty times the drop… and it is considered as if it fell into the food."  When the drop hits the outside the pot in a place parallel to where the pot contains food inside, we must check whether or not the drop is "batel be-shishim" – if the pot contains sixty times the amount of the drop.  Generally the pot will contain enough for bittul to occur, but the Shakh comments, "This refers to rendering the food permissible; the pot, however, is forbidden."  The reason is that the drop touches the pot directly, whereas it does not come in direct contact with the food inside the pot, in which case one would not have to kasher the pot.
     If the drop hits the pot in a place with no food parallel to it on the interior, then the same halakha mentioned earlier applies to the pot.  The food, however, must be removed from the opposite side of the pot, unless the pot is left to cool before its contents are poured out.
     In order to prevent such problems, one should ensure while frying, or while cooking, not to place other types of utensils nearby.
     What is the halakhic status of the surface underneath the grate?  At first glance, it seems that these surfaces present no problem at all, given the fact that they come in direct contact with neither the food nor the utensils.  At times, however, food falls onto the surface and we eat it.  This is very problematic, since quite possibly a dairy food had fallen onto the plate and then a meat food, thus rendering the surface non-kosher.  One must therefore ensure not to eat food that fell onto the surface or place very hot utensils such as a ladel or spatula on it.
     The mishna in Masekhet Makhshirin (2:2) posits, "A bathhouse that is tamei – its steam is tamei."  This mishna establishes the principle that not only can water itself become tamei, but the steam rising from water can likewise become tamei.
     On this basis, the Rosh arrived at a general rule regarding the laws of kashrut (responsa, 20:26):
"That which you asked concerning a dairy pan, if it may be placed in an oven underneath a meat pot: It appears to me that this is forbidden.  And even ex post facto, if it is done, I would consider the pot forbidden, because the steam rising from the pan is like milk, as the mishna states in the second chapter of Makhshirin: 'A bathhouse that is tamei – its steam is tamei.'  We see from all this that steam rising from something is considered like it, and it thus turns out that the steam of a dairy pan is like milk."
The Shulchan Arukh codifies this rule in Yoreh Dei'a (92:5): "A dairy frying pan that was placed in an oven underneath a meat pot: the steam rises, is absorbed in the pot, and renders it forbidden."  Therefore, if, for example, a person places the cover of a dairy pot on a meat pot cooking on the fire, the cover must be kashered.
     This halakha forms the basis of the prohibition against baking dairy and meat foods in the same chamber of an oven, even one after the other.  Since after the meat is baked the oven contains the steam of the meat food, that steam will render non-kosher the dairy food placed in the oven thereafter.  This is indeed the ruling of Rav Moshe Feinstein (Iggerot Moshe, Y.D. 1:40):
"Now in the gas ovens in this country, [regarding the issue of whether or not] there is a concern for steam when cooking an uncovered meat dish, such that it would be forbidden to then afterward cook an uncovered dairy dish… If there was steam, we should not allow cooking exposed meat and dairy foods, even one after the other, until after the passage of a considerable amount of time."
Therefore, it is obviously preferable to purchase an oven with two chambers for baking. 
Even regarding two-chamber ovens, there are different types.  In some ovens, the two chambers share a common back wall, whereas in others they have different walls, such that the oven contains two completely separate chambers.  This second type is the most preferable.  Even among these, however, different kinds of ovens exist.  The ovens sanctioned by the Badatz and Rav Landau have two separate pipes bringing the gas outside the oven.  Others, including the ovens sanctioned by Tzomet, have only a single pipe, through which all the steam leaves.  The Badatz claims that when the steam leaves from the bottom chamber to the pipe, some might enter the upper chamber.  Factually, this is correct, but this seems insufficient a reason to forbid these ovens, because of both the amount of steam that enters the upper oven, and the leniency of a covered pot, as we will see later in our discussion.
     A two-chamber oven is the best solution for this problem.  We will now turn our attention to possible solutions available for those who do not own such an oven, proceeding from the most preferable to the least preferable.
     Rav Moshe Feinstein (Iggerot Moshe, Y.D. 1:59) rules that steam creates a problem only for foods cooked uncovered.  If all foods are covered, we need not be concerned about steam, and one may then cook meat and dairy in the same chamber.  Less preferable a solution is to cover only one of the two types of food cooked – either the dairy or the meat.  One may treat even this solution as "le-chatekhila."
[Care should be taken to place a sheet of tin foil beneath the pan in the event of spill over – M.F. ed.]
     The following solution appears in Rav Ovadya Yosef's comments, in Yabia Omer (vol. 5, Y.D. 7):
"We may therefore permit [cooking dairy] after waiting twenty-four hours from the roasting of the meat, and on a tray designated for dairy foods, on condition that the oven is turned on for around twenty minutes before baking, such that the oven's heat will completely eliminate the small amount of steam, to the extent to which there is [steam] in the oven."
This solution involves two stages: a twenty-four hour waiting period, and preheating the oven before the second baking for around twenty minutes.  The second stage does not require actually twenty minutes, but rather bringing the oven to its maximum temperature and leaving it at that temperature for around fifteen minutes.  One may then bake in the oven on a separate tray.  A similar approach is taken by the Minchat Yitzchak (5:20).
     At first glance, this appears to be a very sound and effective solution.  Why would anyone object to this option?  After all, it fully accommodates the basic principle of "ke-bol'o kakh polto" (utensils/appliances expel taste at the same temperature at which they absorbed it).  The problem with this approach involves a debate regarding this principle.  Does it refer only to the type of kashering, or also to the specific level of the given type of kashering?  Meaning, some authorities hold that this principle establishes only the type of kashering required: hag'ala (immersion in hot water), libun (direct exposure to fire), etc.  But the required level of libun, for example, is determined not by the manner in which the taste was initially absorbed, but rather by the objective definition of libun.  The aforementioned solution thus becomes questionable, given the fact that it does not necessarily achieve a full libun on the oven. 
An additional problem emerges from the ruling of the Magen Avraham (O.C. 506:11), forbidding "le-khatechila" kashering a dairy utensil to use it for meat, or vice-versa.  One therefore should not convert his oven from meat to dairy or vice-versa.  To this, however, one might respond that this ruling was meant only "le-khatechila," and we deal with a situation where no other option exists.
     Some ovens have a self-cleaning feature.  If the oven reaches a temperature of 450 degrees (Centigrade) or higher, then the highest standard of libun ("libun chamur") is achieved, and one may kasher his oven by running the self-clean feature. [Self-cleaning ovens, while affording a le-chatekhila solution halakhically, are not very practical.]
     The next possible solution is to simply wait twenty-four hours before the second baking.  The second dish is then permissible to eat even if it does absorb some of the taste from the previous food baked, since after twenty-four hours absorbed taste becomes pagum (putrid) and therefore does not render the oven non-kosher.
     If one does not wait twenty-four hours, but turns the oven to its highest temperature for around fifteen minutes, he has authorities on whom to rely, and one may eat the food cooked in the oven thereafter. 
Why would this leniency work?
     Firstly, the oven quite possibly does not require libun at all, and requires only hag'ala, since the steam is liquid.  To the extent to which the oven requires only hag'ala, the procedure described effectively kashers it.  This point hinges on a debate among the poskim regarding a case where a dry food item was cooked and the steam, rather than the item itself, came in contact with the utensil.  The Tur (O.C. 451) rules that steam of a cake requires "libun chamur."  Some Acharonim, however, indicate that they rule leniently on this point, and in fact the Mishna Berura makes no mention of the Tur's position in his commentary to this siman.  Thus, this means of kashering might qualify as libun.  Secondly, we deal here with an oven that absorbed taste of heter (permissible food) rather than issur (forbidden food).  Even if an oven that had absorbed non-kosher taste requires libun, perhaps in this situation hag'ala suffices.
     As opposed to ovens, the walls of the microwave do not themselves become hot.  It is rather the waves that heat the food, and the oven in turn becomes hot because of the food.  There have been many halakhic discussions concerning the precise status of microwaves.  It is generally accepted to view microwaves as heating the food directly and treat the utensil as a keli rishon (a utensil in which food was cooked).
     Two problems arise when dealing with microwaves: the steam and the plate.  The best solution is to cover all foods warmed in a microwave.  One must also put an appropriate plate beneath to catch spill over.  Obviously, the most preferable covering is a hermetic covering, and even if the cover contains a few holes to allow gases to escape, this qualifies as a hermetic covering.  The main problem, however, involves warming liquids, because they produce a lot of steam and are difficult to cover.  In such a case, one should preferably place the liquid inside a bag as it is warmed.
     If one cannot cover all foods warmed in the microwave, he can cover either all the meat foods or all the dairy foods.  One must then exercise more caution with regard to the method and standard of covering.
     Where one does not have control over what foods are warmed in the microwave, he can cover food hermetically with two covers and then heat it in any microwave.
     The Shulchan Arukh writes (Y.D. 95:3): "Meat pots that were rinsed in a dairy kettle with hot water at yad soledet [a temperature at which a hand would immediately recoil after coming in contact with it]… If they had grease stuck to them, there must be sixty times more water than the actual grease… "  Meaning, if one washes meat dishes with actual meat on them in a dairy sink with hot water, then the meat must be batel (nullified) by sixty times its quantity of water in the sink.  Otherwise, it all becomes non-kosher.  Care must therefore be taken, particularly if one washes meat and dairy utensils in the same sink at the same time, to avoid this problem.
     According to the Rama (in his glosses to this halakha), this problem exists even if there is no actual substance of meat on the utensils.  A famous debate between the Ashkenazim and Sefaradim surrounds this issue.
     This issue has important ramifications in the army.  For example, at times a meat pot containing tea is left all night, and quite possibly somebody took some tea from the pot with a dairy ladel.  The halakha in this situation would hinge on the debate between the Shulchan Arukh and the Rama; according to the Rama, the utensils are non-kosher.
     Is there a problem washing meat and dairy dishes in the same sink but at different times?
     Ideally, dishes should be washed in different sinks, since the sink can absorb meat and then milk, and thus render the utensils non-kosher.  "Be-di'avad," however, the sink is kosher since we may assume that any taste absorbed becomes battel.  We may add other factors, as well, to permit the use of a single sink when no other solution is practical: the detergent used to wash dishes ruins the taste absorbed, such that it cannot then render a utensil forbidden; the water used to wash dishes generally does not reach the temperature at which taste can be absorbed ("yad soledet bo").  In any case care must be taken to clean the sink well in between use.
     Rav Moshe Feinstein (Iggerot Moshe, Y.D. 1:42) adds that if one has separate racks for meat and dairy, he may use the sink for both even on the level of "le-khatechila."  This only works, however, on the condition that the hot water in the sink never rises high enough to reach the rack, for then the sink absorbs the taste from the utensils, and the racks serve no purpose.
     Some kitchens have sinks with a single wall separating between meat and dairy.  The problem with this arrangement is that the wall absorbs taste from both sinks.  One must therefore ensure that two separate walls divide between meat and dairy, or that there are two separate sinks entirely.