Is My Stove Kosher?

Question #1: Is my stove treif?

“I have always used my stove for both milchig and fleishig, which is what I saw my mother do. But why is this permitted? Food spills from both milchig and fleishig onto the stove burners and gets heated there. Doesn’t that make my stove treif?”

Question #2: Kashering their stove

“My parents do not keep kosher. I have my own pots that I use when I visit their house, but how do I kasher the stove each time I visit them?”

Question #3: Induction stoves

“How do I kasher the induction stove in the house I just moved into?”

Introduction

There are some allusions to the laws of kashrus in this week’s parshah, Devorim. This provides an opportunity to discuss one of the least understood areas germane to a frum household – the status of the stove.

Should I be discriminating?

Although our dairy and meat equipment are always kept separated, in most households, the same stovetop burners are used to cook both milchig and fleishig foods. Most people place a pot of meat on the same burner that earlier in the day may have been cooking something dairy. Why does this not pose a kashrus problem, since we know that food spills onto the stove grates and its flavor burns into the stove? Why doesn’t this make all of our pots treif?

Separate but not equal

At the same time, we will not use a chometzdik stove for Pesach without either kashering it, covering the grates carefully with aluminum foil, or both. If I may use the same stove for both milchig and fleishig, why must I kasher my chometzdik stove for Pesach? Am I being inconsistent?

The induction stove

In addition, our article will discuss a new type of stove now available on the market. The induction stove, marketed as a very energy efficient and safe model, contains its own halachic questions. I will explain shortly how this type of stove operates and then address its unique halachic issues.

In order to understand the halachic background to this issue, we need to explain the issues thoroughly. As always, the goal of our article is not to render piskei halachah, which is the role of each individual’s rav or posek. The purpose of this article is to provide some understanding of the topic at hand.

Introduction #1: Vessel to vessel

When the Torah prohibited eating meat cooked in milk, it also prohibited eating food that contains the flavors of both meat and dairy. For example, if one cooked meat and then milk in the same pot on the same day, meat flavor goes into the dairy product, thus creating a prohibited mix of meat and milk (Shulchan Aruch, Yoreh Deah 93:1). Similarly, the Torah prohibited meat cooked in a pot or on a grill in a way that it will absorb flavor from dairy that was previously cooked in the same pot or on the same grill. For this reason, using a grill that today barbecued meat to make a grilled-cheese sandwich is prohibited min hatorah, since this is halachically equivalent to cooking meat and dairy together.

Not only are we prohibited from eating non-kosher foods, but we are also prohibited from eating food that includes a small taste or flavor of non-kosher foods, such as, when they contain a residue of the non-kosher substance that imparts an enjoyable flavor.

The halachic issue here is whether taste passes from one vessel into another vessel when they touch one another directly, and there is no food or liquid between them. In other words, we know that flavor of food cooked in a pot will transfer into other food cooked in that pot. However, perhaps the flavor transfers only into food that comes in direct contact with the pot. Is there transfer of taste when two pots touch, but there is no food or liquid at the points of contact through which the flavor can pass? Are we concerned that flavor might transfer into the stove grate and then into the food being cooked on top of that grate?

According to some early authorities, flavor does not pass between two vessels, whereas other authorities hold that it does (Hagahos Shaarei Dura [51:3; 56:1], quoting the author of the Terumas Hadeshen). Both opinions are mentioned by the Rema in his Darchei Moshe commentary on the Tur, Yoreh Deah 92:9.

Here are two practical examples that the Rema discusses there:

  1. Someone placed a covered milchig frying pan containing dairy ingredients on top of a stove. He then placed a fleishig pot in which meat is cooking directly on the covered pan cooking dairy. According to the lenient opinion, that of the Issur Vaheter (31:17), the pots and the food all remain kosher, because although the pan is cooking real dairy and the pot is cooking meat, no absorption of flavor passes from one vessel to the other. In other words, in this case, none of the dairy flavor transfers from the milchig pan to the fleishig pot resting on top of it, and no meat flavor transfers from the fleishig pot to the milchig pan on which it is resting.

However, there is a stricter opinion, that of the Hagahos Shaarei Dura, who contends that even if the area between the pot and the pan cover is completely clean and dry, the food and the vessels are now non-kosher, because we do view that there was transfer of flavor from the milchig pan to the fleishig pot, and vice versa.

  1. Two pots are cooking on the stove, one containing meat and the other dairy, and they touch one another. According to the lenient opinion, the food and the vessels remain kosher, since no food taste will transfer between the outside of the two pots (Mordechai, Chullin #691), whereas, according to the strict opinion, everything is now non-kosher: the food must be disposed of and the pots requires kashering.

How do we rule?

The Rema (Yoreh Deah 92:8) rules that in both of these instances the food may be eaten, and both pots remain kosher. However, he rules that one should be careful not to allow this to happen. Thus, we see that the Rema follows the opinion of the Mordechai that absorption does not pass from one vessel to another, unless there is food or liquid connecting them, although he contends that this is permitted only after the fact, bedei’evid.

Another application – the stovetop

According to this ruling, placing a kosher pot on top of a treif, but clean and dry, stovetop does not render the pot or its contents non-kosher, even if the stovetop absorbed non-kosher food earlier in the same day. This is because, although the stove is non-kosher, no non-kosher absorption transfers from the stove, which is dry, into the pot, unless there is either food or liquid on top of the stove.

Why are we not concerned that there is food or liquid that spilled on the stove which could allow transfer of taste from the non-kosher stove into the food and then into the pot resting on top of the stove? Later authorities explain that, since stovetops get very hot, one can presume that any liquid that lands on them will evaporate almost immediately. In addition, the hot stovetop will burn food that splatters on them beyond edibility. Therefore, one need not be concerned about liquid or food that splatters on the stovetop (see Mishnah Berurah 451:34; Shu”t Igros Moshe, Orach Chayim 1:124, Yoreh Deah 1:59). We will return to this part of the discussion shortly. But first, we will discover that the Rema, himself, in a ruling on a related topic, seems to contradict himself!

Why is this night of Pesach different?

When discussing the laws of koshering for Pesach, the Rema (Orach Chayim 451:4) rules that a chometzdik stovetop must be kashered with libun, which means that one must use direct heat to burn off the prohibited residue that has absorbed into it. The question is why this should be necessary. Assuming that the stovetop is clean and dry, no chometz that has absorbed into the stove will transfer to the Pesach pots that are placed upon it.

Among the acharonim, we find three approaches to explain why the Rema rules that one must kasher the stovetop for Pesach. The Mishnah Berurah (451:34) and Rav Moshe Feinstein (Shu”t Igros Moshe, Orach Chayim 1:124 and Yoreh Deah 1:59) rule that this is a special ruling germane to the laws of Pesach — we act more strictly regarding the laws of Pesach than the halachah otherwise requires. According to this approach, there is no halachic requirement to kasher a treif stovetop before using it, nor is there any halachic problem with using the same stove burners for both milchig and fleishig.

Other authorities disagree, contending that although the Rema ruled that when the two pots, one containing meat and the other dairy, touch, absorption does not transfer directly from one vessel to another, this ruling is true only after the fact, but that one may not rely on this ruling lechatchilah. The result of this approach is that we are not permitted to use a non-kosher stovetop without kashering it – although if someone did use it, bedei’evid, the food and the pots are permitted. It is then very obvious why the Rema ruled that one must kasher a chometzdik stove before using it for Pesach. It is not a chumrah for Pesach; it is halachically required. Thus, we find that the Chachmas Odom (74:4) rules that someone who purchased from a gentile a tripod meant for cooking on top is required to kasher it with libun, because food spills onto it. In a similar approach, the Ksav Sofer concludes that anyone who is G-d-fearing should be careful not to use the same part of the stove for cooking both milchig and fleishig, but he should have separate designated facilities (Shu”t Ksav Sofer, Yoreh Deah #54).

According to this approach, one may not use a treif stove without kashering it, and one should preferably not use the same stove burners for both milchig and fleishig. Rather, one should designate that when cooking milchigs one uses only, say, the left burners on the stove, and when cooking fleishig, one uses the right burners.

A third approach is that a small amount of flavor does seep through from one vessel to another. This small amount is nullified and, therefore, not a kashrus concern germane to other prohibitions. However, we are strict and do not permit even a minute amount of chometz on Pesach, and for this reason the Rema is stricter regarding Pesach than he is in regard to milchig and fleishig. (See Igros Moshe who mentions this approach, but rejects it.)

Thus, we have three clearly dissenting approaches, one contending that one is required to kosher a treif stove grate or stovetop before using it, and the other two contending that one is not required to do so. This dispute will result in a major question regarding question #2: “My parents do not keep kosher. I have my own pots that I use when I visit their house, but how do I kasher the stove each time I visit them?”

According to the more lenient approach we have mentioned, the stove may be used without any kashering at all, which will make matters easier for our questioner. The other approach may not be so lenient, although it is possible that they would agree: Since it is permitted, bedei’evid, this establishes a basis to permit use of the stove under extenuating circumstances, such as the case at hand, without kashering it first. This decision I leave to the consulted rav or posek.

Induction stoves

At this point, let us examine the third question with which we opened our article:

“How do I kasher the induction stove in the house I just moved into?”

Firstly, what is an induction stove?

Considered the most energy-efficient and safest household stove, the induction stove contains no open flame. Instead, a coil of copper wire is located underneath the cooking pot, which must be made of iron or steel for the stove to work. Electric current flows through the coil, which produces a magnetic field, which in turn creates an electric current in the pot. Current flowing in the metal pot produces resistive heating in the pot, which cooks the food. Heat is created exclusively in the pot or pan; there is no flame or hot electric coil.

The surface below the cooking vessel is no hotter than the vessel; only the pot or pan generates heat. The stovetop is made of material which is a poor heat conductor, often glass, so that only a relatively small amount of heat is transferred from the pot to the cooking surface, usually not enough so that after the cooking vessel is removed it would burn someone seriously.

Because induction heats the cooking vessel itself, the possibility of burn injury is significantly less than with other methods; the surface of the cooking top is heated only from contact with the vessel. Since there are no flames or red-hot electric heating elements as found in traditional cooking equipment, an induction stove is ideal.

From a halachic perspective, there are several ways that an induction stove should be treated differently from a conventional stove. Since the cooking surface is not directly heated, spilled food does not burn on the surface. This means that food from spills will absorb into the cooking surface, rather than becoming burnt up. In addition, one cannot cover the cooktop with aluminum foil or anything else. The foil may melt and cause permanent damage or cracking of the top.

On the other hand, the induction stove does not change the concept, accepted by most authorities, that taste does not transfer from one vessel to another without food or beverage between them.

So, now we need to analyze the three halachic questions mentioned above, but specifically directed to the induction stovetop.

  1. Is one required to kasher an induction stovetop when it was previously used for non-kosher?
  2. May one use an induction stove interchangeably for meat and dairy products?
  3. How would one kasher an induction stove for Pesach use?

A treif inducer

Above we cited the dispute among halachic authorities whether one is required to kasher a stovetop that was used for non-kosher. According to some authorities, one is technically not required to kasher a stovetop, since the halachah is that taste does not transfer from one vessel to another. This line of reasoning should apply equally to an induction stove. However, the other reason to be lenient, that the food matter is constantly burning off a regular stovetop, does not apply to the induction stove. For this reason, a rav may feel that one is required to kasher an induction stove, which may be practically impossible, as I will explain in the next paragraph.

When a vessel or other item absorbs food directly over the flame, the halachah requires that kashering such an item requires libun, direct application of heat. In the case of an induction stovetop, this would be impossible. The stovetop, most often made of glass, usually cannot withstand the heat that would be necessary to kasher. The halachah is that one is not permitted to kasher an item that might crack or break while being kashered, because of concern that the process will not be performed properly.

On the other hand, someone could argue that since the induction stovetop becomes hot only because of the pot resting on it, that it does not require libun, but that it is considered equivalent halachically to something onto which hot foods are poured. These items require only iruy, pouring boiling water onto them, to kasher them, something that can certainly be done to an induction cooktop.

From milchig to fleishig:

Again, I mentioned above the dispute among authorities whether one may use a stovetop for both milchig and fleishig. Certainly, the prevalent practice is to use the same stovetop for both, and rely on the fact that since the surface is clean and dry, no absorption of residual food taste in the cooktop transfers to the pots or pans placed on it. This line of reasoning can also be applied to the induction stove. I would caution someone who has an induction stove to be careful to wipe off spills when they occur, since the spillage does not burn off, as it does with a conventional stove.

For Pesach use:

As we learned above, the Rema required kashering a stovetop for Pesach with libun. An alternative way to prepare a stovetop for Pesach is by covering it completely with aluminum foil, or the like, which now prevents chometzdik absorption in the grates from transferring to the Pesach pots.

However, neither of these kashering procedures can be done with an induction stovetop. The cooktop may crack if direct heat is applied, and it cannot be covered. Thus, the only heter that might apply would be to pour boiling water onto the surface and rely on this being a sufficient kashering procedure. Someone with this shaylah should discuss it with his posek.

Conclusion

Based on the above information, we can gain a greater appreciation of how complicated even a relatively common shaylah might be. We certainly have a greater incentive to understand all the aspects of maintaining a proper kosher household. We should always hope and pray that the food we eat fulfills all the halachos that the Torah commands us.