Reviewed March 2024

To download and print a handy summary of these halachos, click here.

Cooking in the modern kitchen is a whole new experience. Technological advances have taken the old stovetop and oven and upgraded them to be safer, more efficient, and “smart” for today’s lifestyle. They are also far more complicated. With these transformations, the observant Jew is faced with challenges that did not confront him in the past.

To understand how these changes affect the halachic use of ovens and cooktops on Shabbos and Yom Tov, it is worthwhile to review some laws and concepts as they relate to cooking on Shabbos and Yom Tov.

A. Terms and Prohibitions Pertaining to Food Preparation on Shabbos and Yom Tov

Definitions of Basic Terms

Melacha	A melacha is a Torah prohibited act derived from the constructive acts performed in erecting the Mishkan . These forbidden acts are known as melachos.
Bishul	Bishul refers to the melacha of cooking. The prohibition of cooking on Shabbos is defined as the act of using heat to make a substance edible or to change its current state.
Yad Soledes Bo	In order for food to be considered hot, the food must reach a temperature of yad soledes bo (120°F), hot enough to cause one to withdraw their hand due to the heat. If the food will not reach a temperature of yad soledes bo , it is not classified as cooking.
Ha’avara	Ha’avara is the act of burning. Lighting a flame on Shabbos is prohibited as it is written, “Do not burn fires in your homes on the Shabbos day.”1
Mosif Ha’avara	Adding to an existing flame is also prohibited on Shabbos. This is referred to as Mosif Ha’avara .
Gram Ha’avara	One may not perform an action that will indirectly cause the flame to ignite. The term for indirectly causing the flame is Gram Ha’avara .
Aino Mechaven	One is liable by Torah law for a prohibited action when the result was intended . Where one’s intent in performing the physical action is not for the prohibited reaction, they are not liable. This is called Aino Mechaven , which literally means that there was no intent to perform the actual melacha (e.g., dragging a bench on the ground on Shabbos to bring it to another location is permitted , even though it may make a groove in the ground [which is the melacha of Choreish , plowing]).
Psik Reisha	If the unintended consequence is the anticipated outcome of the activity, this is called a Psik Reisha . This type of activity is prohibited because it is as if one had intentionally performed a prohibited action (e.g., dragging a heavy bench on soft earth where it will make a groove in the ground).
Psik reisha d’lo nicha lei	On Shabbos, when the resulting consequence is neither wanted nor intended, it is classified as a psik reisha d’lo nicha lei , which is permitted by Torah law but prohibited by rabbinic law.2
Grama	The halachic interpretation of a melacha is the action that one performs which causes a direct result. For example, when one strikes a match he directly causes a fire to ignite. When the resulting prohibited action is an indirect result of one’s action, it is called a grama . For example, setting a mouse trap is a grama for the melacha of Tzod (hunting). A grama of a melacha is permitted by Torah law but is rabbinically prohibited. NOTE: Where there is a combination of factors that individually may have been restricted by rabbinic law, there may be room for leniency when combined. Therefore, where a grama will cause a melacha to be performed that is unintended and unwanted on Shabbos (i.e., lo nicha leih ), the action may be performed. This is the basis for allowing one to open a refrigerator door on Shabbos. In such a case, a thermostat will sense the change in temperature and cause the compressor motor to run; this is considered a grama . The running of the motor gives off sparks of fire which are not wanted or intended; thus, the melacha taking place is lo nicha lei . Opening the refrigerator results in a grama of an unintended and unwanted melacha . In the same vein, one may open an oven door on Shabbos when one removes all the food from the oven. The resulting grama (i.e., the melacha of Ha’avara ) is unwanted and unintended.

Rabbinic Ordinances Regarding Food Preparation

Many rabbinic laws were initiated to prevent one from transgressing the Torah’s prohibitions. They are intended to distance us from what is prohibited, as well as to prevent us from performing actions which can be misconstrued with a prohibited melacha. Here are two important rabbinic prohibitions.

Prohibition of Shehiyah

One is prohibited to leave the food on or in the place where it will be cooking, even if it was placed there before Shabbos. There is concern that leaving food that is not ready to be eaten on the cooking surface or in an oven may lead one to add to the heat on Shabbos. This is the rabbinic prohibition of Shehiyah. One may not leave uncooked or partially cooked food on/over a heat source before Shabbos. The rabbis were concerned that one may adjust the heat to enhance the food. In the past, when cooking was performed directly over burning coals, there was a concern that someone might stir the embers which would add oxygen and increase the heat. By stirring the embers, one transgresses two Torah prohibitions: burning a fire on the Shabbos day (Ha’avara), and cooking (Bishul) if the food is not yet cooked. In order to prevent any wrongdoing, the rabbis decreed that unless the food is edible before Shabbos3 one may not leave it on the cooktop or in the oven once Shabbos begins, unless the embers are removed or covered to prevent someone from stirring them.4 In lieu of covering the coals, we have the custom of placing a blech5 over the flames before Shabbos. It should be noted that the main function of the blech is to make sure that one does not adjust the fire. Therefore, with a modern oven or cooktop, one should cover the temperature controls in addition to covering the flame with a blech.

Prohibition of Chazara

Another rabbinic prohibition is Chazara, returning cooked food to the heat source on Shabbos. Even if the food is still hot and fully cooked, one may not return it to an oven or a covered stove unless it was removed with the intention of being returned; it may not leave his hand from the time it was removed to the time it was returned to the heat. This certainly would prohibit taking a cold pre-cooked food and placing it on a blech on Shabbos. This rabbinic decree was instituted because by placing food on the heat it appears as if one is beginning to cook. It is important to note that reheating cooked foods that are liquid or contain liquid may be a transgression of the Torah’s prohibition against cooking on Shabbos. Solid foods that have been fully cooked before Shabbos may be reheated (e.g., kugel or a dry roast) on Shabbos. However, due to the prohibition of Chazara, reheating must be done in a way that cannot be confused with cooking. Therefore, one may place a kugel or challah on top of a pot of food that is on the blech but not on top of the blech itself.

Additional Terms Pertaining to Melacha on Yom Tov

Meleches Hana’a	Meleches Hana’a generally refers to activities performed for food preparation and personal needs on Yom Tov.
Meleches Avoda	Meleches Avoda refers to all non-food related activities.
Molid Aish	Molid Aish refers to the creation of a flame.
Kibuy	Kibuy refers to extinguishing a flame.
Gram Kibuy	Gram Kibuy refers to extinguishing a flame through indirect means.

B. Marketing Terms That Can be Misleading

Two terms are frequently used by appliance companies to market their products that can be downright confusing, even misleading kosher consumers. These are delineated here:

Sabbath Mode

This is a feature that enables the consumer to operate their oven so that they can cook on Yom Tov. Sabbath Mode does allow the kosher consumer to open the oven door without enabling lights, icons, or sounds. A better term would be Yom Tov Mode. See discussion of Sabbath Mode in the article below.

Warming Drawer

A warming drawer is a small thermostat-controlled appliance that is either part of a range or installed as a standalone unit. Its description as a ‘drawer’ attests only to its convenience but belies its utility as a functioning heating appliance. For accuracy’s sake, it should be called a Warming Oven as it is halachically no different than an oven. STAR-K gets an untold number of calls from consumers who are surprised to discover that a warming ‘drawer’ may not be used on Shabbos.

C. Sabbath Mode: A Brief History and Overview

Appliance manufacturers, with the aid of modern technology, have designed kitchen appliances to be safer and more efficient while incorporating various features to enhance operation. However, the integration of this technology can pose a challenge to their proper use on Shabbos and Yom Tov.

In 1997, a historic technological project was launched between a major appliance manufacturer and a kosher certification agency, specifically STAR-K. Prior to that time, many of their appliances did not conform to halachic guidelines. Whirlpool Corporation (manufacturer of KitchenAid) approached STAR-K to help modify their ovens for use on Shabbos and Yom Tov. Following some adjustments, a successful mode was developed. Whirlpool called this “Sabbath Mode” and was awarded a patent in 1998 for this concept.

Subsequently, some technologically advanced refrigerators have also acquired Sabbath Mode certification. These will be discussed below as well.

This article is merely an overview of the application of modern technology to appliances and how it affects the Orthodox Jewish consumer. For certified models and guidelines for their proper usage, please check the appliance page on the STAR-K website. They are listed there by company and specific model number.

STAR-K certification on appliances falls into one of two categories:

Sabbath Mode

This includes models with unique software/hardware specifically designed to address halachic concerns for use on Shabbos and Yom Tov.

Sabbath Compliant

This includes simpler models (aka, ‘old fashioned’) that were not built with the more recent innovations (e.g., 12-hour shut-off, digital controls) that now pose halachic concerns for the Sabbath-observant consumer. Consequently, the manufacturer requested an assessment by STAR-K if they could market these models as ‘Sabbath Compliant.’

Designating appliances as either having ‘Sabbath Mode’ or being ‘Sabbath Compliant’ was meant to help the consumer avoid making a purchase that would pose a halachic difficulty on Shabbos and Yom Tov.

It is important to note that not all Sabbath Mode models offer the same features. If you have a STAR-K certified Sabbath Mode oven, please check the STAR-K appliance page to see which features are available on your particular model, or contact STAR-K office at 410-484-4110.

D. Ovens

Sabbath Mode Ovens

Sabbath Mode ovens are designed to bypass many of the practical and halachic problems posed by the modern oven. When in Sabbath Mode, no lights, digits, solenoids, fans, icons, tones or displays will be activated/modified during normal use.

A safety feature in the newer ovens automatically shuts the oven off after 12 hours of operation. Although this safety feature is very important, it creates a problem when preparing food for the daytime meal which takes place more than 12 hours after the onset of Yom Tov. For all types of Sabbath Mode ovens, the 12-hour cutoff is bypassed.

For Sabbath Mode ovens with the delay feature, one may raise or lower the temperature of the oven on Yom Tov – but not on Shabbos – without affecting the heating element or glow plug. This is because the computer does not directly react to the change in settings. The oven will adjust the setting only after a delay. This means that turning on the heating element or glow plug is a grama – an indirect result of an action. Therefore, since a grama is permitted on Yom Tov, one may actually adjust the temperature on the oven during Yom Tov.

For Sabbath Mode ovens without the delay feature, the temperature may be raised only when power is flowing to the oven and lowered when power is not flowing to the oven, as indicated by the readout on the display.6 (Note: The oven will still have to be set to ‘Sabbath Mode’ to prevent issues with the display.)

IMPORTANT: Sabbath Mode does not permit us to turn these appliances on or off during Shabbos or Yom Tov nor does it allow us to use these appliances completely at will on Shabbos or Yom Tov. Rather, it enables us to use these appliances within the guidelines of Halacha as posted on the STAR-K website.

In most Sabbath Mode ovens, the door plunger switch is disabled so that it will not directly cause any electronic reaction. On some of these ovens, the cavity light will remain either on or off, depending upon how Sabbath Mode was entered; the disabled door plunger switch will prevent the oven light from going on/off as the door is opened/closed. In some models without the plunger switch override, the bulb must be unscrewed or the light left on for the duration of Shabbos or Yom Tov.

Sabbath Compliant Ovens

Ovens certified as Sabbath Compliant do not have a digital temperature readout. They have the same basic features as those with the Sabbath Mode, except no delay is built into the set temperature change process.

On some models, adjustment of the set temperature may be possible on Yom Tov provided they have an indicator light that cycles on/off as power flows to the heating elements. One can raise the temperature when the light is on and lower it when it is off. On Sabbath compliant models that do not have a cycling indicator light, the set temperature selected before Yom Tov cannot be adjusted on Yom Tov. STAR-K’s appliance page has details about specific Sabbath Compliant models.

Time Bake Feature

Some ovens can be programmed to turn off at a preset time. This feature is known as Time Bake. In many models, when the time has elapsed and the oven shuts off, it will either sound a bell/buzzer that displays an icon or readout (such as the word END) to indicate that the oven is off. On some oven models, the sound will chime indefinitely and the light will stay on until it is manually turned off or until the door is opened, which cannot be done on Shabbos or Yom Tov. On Sabbath Mode oven models that include the Time Bake feature, the buzzer or readout is eliminated.

(NOTE: Once Time Bake goes off, the oven cannot be used again for the duration of Yom Tov.)
STAR-K’s appliance page lists models that have the Time Bake feature without these drawbacks when in Sabbath Mode.

Warming Drawers

Warming drawers should be treated as standard ovens, since they present the same issues. They are thermostatically controlled, and their lowest temperature is often above 120°F (yad soledes bo). As is the case with standard ovens, all food must be placed in the warming drawer before the start of Shabbos.

Power Failures – IMPORTANT NOTE

Note: For safety reasons, most ovens will not return to an operational state after a power failure. In some cases it may not resume Sabbath mode. Some exceptions are noted on STAR-K’s website.

E. Smart Refrigerators

Not to be left out in the cold, refrigerators have also succumbed to the incorporation of modern technology. Additionally, there are old issues which still require resolution that include when to open the refrigerator door on Shabbos and what to do about heating elements that turn on to defrost the coils. STAR-K has developed a set of criteria through which the latest technological advancements are employed to alleviate these problems.

Upon entering the certified mode (referred to as either ‘Sabbath’ or ‘Holiday’ mode), the consumer need not worry about lights, digits, icons, tones, alarms, solenoids or fans being activated/deactivated when opening or closing the door.

Furthermore:

• A built-in delay prevents the compressor from turning on immediately after the door is opened.
• The Open Door Assist mechanism, if a feature of the refrigerator, is disabled.
• The defrost cycle operates solely on clock time, without any feedback from the consumer’s use of the refrigerator. (Some manufacturers control the defrost cycle by actually counting the number and length of door openings, which may present a halachic problem.)
• Finally, the ice and cold water systems are deactivated since they invariably use electrical solenoids and motors to function.
• After a power failure, units are returned to the certified mode.

Now that we have defined halachic terminology, discussed some of the basic principles of warming food on Shabbos and Yom Tov, and reviewed Sabbath Mode, let us begin by examining what happens in practice when using an oven or warming drawer on Shabbos.

F. Oven Use on Shabbos

Ovens and Warming Drawers

As previously noted, aside from the prohibition of cooking on Shabbos, there is a prohibition against initiating a fire or causing increased burning. In the case of thermostatically controlled ovens and warming drawers, opening the oven or warming drawer will cause a mechanism to increase burning in order to compensate for the loss of heat by opening the door or drawer. The resulting effect is a grama of Ha’avara, which is not permissible on Shabbos. However, as explained earlier, where one does not want or intend for an action to take place and has no need for its result, the initial action is prohibited by rabbinic law only. When coupled with the fact that the ensuing melacha is a reaction that was brought about indirectly and initiated through a grama, there is room for leniency and the initial action is permitted.

Therefore, food left in the oven or warming drawer from before Shabbos may be removed on Shabbos despite the fact that this action will eventually cause the oven to produce additional heat. This is because removing the food results in additional burning that is not wanted or intended. However, this can be said only when all of the food is removed at one time. If some food remains in the oven to be heated, the additional burning caused by opening the door is viewed as intentional and is, therefore, prohibited. Most warming drawers and ovens are thermostatically controlled and would fall into the above category.

If a warming drawer is not controlled by a thermostat, one must check with the manufacturer to be sure that opening the drawer will not turn off the heating element. As per the rule regarding stovetop controls and the rabbinic laws of Shehiyah, if there are multiple temperature settings, the temperature controls must be covered to prevent one from changing the setting on Shabbos. Even when the warming drawer is not controlled by a thermostat and opening the drawer will not affect the flow of power to the heating element, one cannot place food into the warming drawer on Shabbos if its operating temperature is higher than yad soledes, 120oF. This is prohibited under the laws of Chazara.

Induction Cooktops

An induction cooktop heats ferrous metals using strong magnetic fields. By placing or removing an iron vessel on the induction cooktop, one will initiate or stop the process of heating the metal. Therefore, induction cooktops should not be used on Shabbos or Yom Tov.

Sabbath Mode Ovens

Due to the halachic complications resulting from technological innovations, STAR-K has been working with some manufacturers to design ovens that meet the needs of the Sabbath-observant consumer. Popular features found in many new ovens that pose a problem on Shabbos or Yom Tov include: 12-hour safety cutoffs; lights, icons and temperature displays that may be turned on or off by opening the oven door; and Time Bake features that must be manually turned off in order to silence the buzzer. In STAR-K certified models, many of these features are disabled.

Some Sabbath Mode features, such as temperature adjustment, are quite practical and allow for easier use of the ovens on Yom Tov when restrictions of cooking and burning are lifted under prescribed conditions. However, the Sabbath Mode features do not in any way circumvent the regular restrictions involved in food preparation on Shabbos Kodesh. The laws of Bishul, Ha’avara, Shehiyah, and Chazara must still be observed even when using a Sabbath Mode oven. Please note that the Sabbath Mode programming is limited to ovens and does not apply to the use of the stovetops. Some exceptions are listed on the STAR-K website.

G. Oven Use on Yom Tov

Yom Tov celebrations could never be complete without the traditional piping hot delicacies from past generations. However, the kosher homemaker must be well educated on how to prepare Yom Tov meals without fear of transgressing a Torah or rabbinic prohibition. We will start by discussing the different conceptions of ‘work’ as they relate to Yom Tov, and how they are similar to or different from Shabbos.

“Work” on Shabbos vs. Yom Tov

The Torah mentions the prohibition of work on Shabbos as follows, “Do not do any melacha (i.e, work prohibited on Shabbos).”7 This prohibition refers to Meleches Avoda, namely, any work performed for either food preparation or general labor purposes. In contrast, when stating the prohibition of melacha on Yom Tov, the Torah qualifies the prohibition by writing, “You shall not do laborious work.”8 The Torah issues the commandments associated with the Yom Tov of Pesach by stating, “No work may be done on them (first and seventh day of Pesach), except for what must be eaten for any person, only that may be done for you” ( Shmos 22:16).

The Ramban explains that the contrast of terms (‘work’ versus ‘laborious work’) used for Shabbos and Yom Tov indicates the difference between melacha in general (otherwise referred to as Meleches Avoda) and Meleches Hana’a. Meleches Hana’a is work performed to prepare food and for personal comfort. Where the Torah commands us about the laws of Pesach, the term Meleches Avoda is not used in the prohibition. However, the Torah immediately includes the clause allowing melacha for food preparation.

This being said, please note that not every melacha may be performed for the purpose of food preparation. Only those melachos which could not have been performed before Yom Tov with the same result may be performed on Yom Tov. Therefore, one may not originate a flame on Yom Tov since one could have left a fire burning from before Yom Tov. The prohibition of starting a new flame is referred to as Molid, giving birth to a new entity.

Melachos which are commonly performed for bulk processing of food (e.g., harvesting and grinding) are prohibited on Yom Tov. Melachos regarding the processing of bread, from the kneading of the dough and onward, are permitted on Yom Tov. Any processes that occur before kneading (e.g., sifting and grinding) are prohibited. The focus of this article deals primarily with melachos associated with cooking on Yom Tov (i.e., cooking, burning of a flame) and extinguishing a flame. It is important to note that melachos permitted for food preparation or other Yom Tov necessities may be performed only if the intent is to derive benefit from action on Yom Tov. One may not cook food on Yom Tov for use after Yom Tov. In fact, one may not cook food on the first day of Yom Tovfor consumption on the second day of Yom Tov. This is because the second day is a holiday by rabbinic law only.

Therefore, one must be sure not to engage in any melacha for the second day until the first day has passed and the next night has begun.9

With these halachos in mind, let’s take a look at how the rules of Bishul on Yom Tov apply when we set the controls of our ovens and cooktops for Yom Tov.

Electric Cooktop

Turning on an electric stovetop to warm food will initiate the flow of electricity to the burner. This is called Molid Aish. Halachic authorities have determined that electricity used as heat or light is considered fire. Consequently, by turning on the burner one is creating a new fire. This action could have been performed before Yom Tov and is prohibited because of Molid Aish. Turning the dial on an electric stovetop may also initiate a light or icon on a control panel which would otherwise be turned off. This may be a transgression of the melacha of Kosev, writing, as well as Molid.

Even when the electric burner is left on from before Yom Tov, if one wishes to adjust the temperature of the burner there is further reason for concern. This is because as a rule one does not know if there is an electric current running to the element at the time he makes the adjustment. Even when an indicator light displays that a burner is turned on, this may not attest to electricity flowing to the burner at that particular moment. Rather, it may indicate that the element is set to maintain the desired temperature adjustment by turning on and off at predetermined intervals. As a result, when one adjusts the temperature upwards on Yom Tov he may be initiating the flow of electricity at a time that it was otherwise not flowing. As previously noted, this is prohibited due to Molid.

To circumvent this prohibition, an electrician can attach a current indicator light that is activated by the actual flow of electricity to the burner.10 This would show whether or not current is flowing to the burner. When electricity is flowing, one may raise the temperature in order to enhance cooking.

Lowering the heat setting on an electric stovetop on Yom Tov is also not without its halachic ramifications. We know that extinguishing a burning log constitutes the melacha of Kibuy.

Lowering the heat setting of a stove on Yom Tov may be associated with the melacha of Kibuy. Therefore, this can be done only when it is for the benefit of the food so that it will remain warm but not burn. One may not turn off the burner completely. If there is a current indicator light showing when power is flowing to the burner, one must be careful to lower the burner only when the indicator light is off.

NOTE: Most stovetops that are supplemented with a Sabbath Mode oven have not been engineered to allow the adjustment of the stovetop temperature. The stovetop must be treated as a conventional cooktop, as described above. (See specific model listings for some exceptions.)

Induction cooktops use electricity to create a magnetic field that will heat ferrous metal. These units react to the placing or removing of a pot onto the cooking surface and, therefore, cannot be used on Shabbos or Yom Tov.

Sensi-Temp Burners

GE coils with Sensi-Temp technology use a sensor to reduce the risk of cooking fires. The sensor detects the temperature of your cookware. If the cookware gets hot enough to ignite oil, the coil shuts off. Once the cookware cools down to a safe temperature, the burner cycles back on.

A heat-sensitive Sensi-Temp burner may be used on Shabbos/Yom Tov in the same manner the burner was used before Sensi-Temp was installed. On Shabbos, however, if a pot of food on a blech is removed, it may not be returned to the blech even if all the criteria of returning (Chazara) are met. This is because the returned pot will likely lower the temperature of the blech and cause the burner to cycle back on sooner.

Gas Cooktop

Not so long ago, the standard gas cooktop had a pilot light which was a constantly burning flame from which the burner drew its fire. If one has such a cooktop, he may turn on a burner during Yom Tov as he will not be initiating a flame. Due to safety concerns, however, the old pilot flame models have been phased out. Instead, cooktops are now fitted with electronic igniters which spark at the base of the burner to ignite the flame; these are prohibited on Yom Tov. One may turn on a burner only if he can do so without causing the electronic igniters to engage. If it is possible to activate the gas flow without engaging the electronic igniter, the burner may be lit by holding a pre-existing flame to the burner (from a candle or a match lit from another burner) when turning on the gas. The easiest option would be to turn on the burner before Yom Tov. It goes without saying that one may increase an existing flame on Yom Tov when necessary for food preparation.

As is the case with an electric stovetop, one can only lower the flame on a gas burner when doing so is for the benefit of the food. An example of this is keeping the food warm while preventing it from burning. However, one may not turn off the flame completely.

Simmer Setting

A gas (or electric) cooktop with a simmer setting is designed with a double-flame ring. When set, one flame is extinguished, leaving only the smaller flame. Use of a simmer setting is forbidden on Yom Tov, even for cooking purposes.

Electric Ovens

As with cooktops, one is forbidden to directly initiate a fire or heat to an electric coil due to the prohibition of molid. If the oven was turned on before Yom Tov, the temperature setting may be raised as necessary for cooking if one is sure that electricity is flowing to the element at that time or there is no digital readout. Also, one may not cause a light or icon to go on during Yom Tov. If a light goes off and on indicating when power is flowing to the heating element, then the temperature may be raised when the light is on.

Generally speaking, one may lower the oven temperature provided it is necessary for food preparation for Yom Tov and a light or icon will not turn off when doing so.

If an indicator light displays when power flows to the oven, one may lower the oven temperature when power is not flowing (indicator light is off ) even if it is not needed for the food.

Some Sabbath Mode ovens are designed to work on a delay when in Sabbath Mode, and the display will not change. Furthermore, this feature permits raising the temperature on Yom Tov at any time, regardless of when power is flowing to the oven. This is because when one adjusts the dial or keypad, it is not directly causing the temperature of the oven to change. Therefore, this action is considered a grama, an indirect action, which will cause the temperature to be raised. Even with these types of ovens, it is better to lower the temperature only when necessary for food preparation or enjoyment of the Yom Tov. (Other features of Sabbath Mode ovens are discussed later in this article.)

Gas Ovens

Older ovens were ignited with a pilot light. As explained earlier, this is a small flame from which the oven drew its fire when turned on. In halachic terms, this allowed the user to turn on the oven during Yom Tov without a question of transgressing the prohibition of Molid.

As with gas cooktops, new ovens are equipped with electronic igniters commonly known as a glow plug. When turning on the oven, the power to the glow plug is initiated. When the glow plug is hot enough, gas begins to flow and starts the flame. When the oven chamber reaches the temperature set by the thermostat, it turns off the flow of gas and electricity. As the chamber loses heat, the oven restarts the glow plug which in turn restarts the gas in order to bring the chamber back to the required temperature. Since one may not directly initiate the flow of electricity to the glow plug during Yom Tov, he must turn on the oven before Yom Tov.

When raising the temperature of the oven during Yom Tov, one must be sure that he is not initiating the electric current to the glow plug. Therefore, if one sees the glow plug glowing (detectable because it gives a bright orange light, which can be seen through the side vents on the floor of the oven) or if the flame is on, one may raise the temperature. As discussed earlier with regard to stovetops, one may lower the oven setting only when needed in order to benefit the food. It is important to note that some ovens will display a digital readout of the temperature when it is raised or lowered. This would pose a halachic question of writing and erasing, both of which are prohibited acts on Yom Tov.

H. Commonly Asked Questions

Now that we have reviewed the basic rules, let us look at some frequently asked questions about oven and stovetop use on Shabbos. The responses have been provided by Rabbi Moshe Heinemann, shlit”a, STAR-K Rabbinic Administrator.

Q. I have a smooth-top electric stove. The manufacturer says that this should not be covered or it will crack. Can I leave my food on the smooth cooktop on Shabbos without a blech?

A. It is customary to cover the heat source, as was done in the past when one cooked directly on embers. The concern at that time was to prevent stirring the embers to add heat. As noted earlier in the introduction, today the primary concern is that one should not try to raise the heat so that the food will cook faster. When one cannot place a blech on the stovetop, it is sufficient to cover the controls and leave the cooked food on the stovetop.

Q. During Shabbos, may I adjust the temperature of an oven that has a Sabbath Mode feature?

A. No! The temperature adjustment feature in the Sabbath Mode oven is for Yom Tov use only. (This issue is addressed in a Kashrus Kurrents article entitled Oven Kashrus: For Yom Tov Use.) On Shabbos, one may not adjust the temperature as this would cause the fire to burn or be extinguished. The Sabbath Mode does not permit one to place food in the oven to cook or reheat on Shabbos.

Q. May I leave cooked food inside an oven that was turned on before Shabbos?

A. Yes. However, due to Shehiyah the controls for the oven should be covered or taped. It is customary to cook all food before Shabbos to the point that it is edible for the average individual.

Q. May I take out some food from the oven and leave the rest to remove later?

A. No. When one opens the oven door, he is letting cool air into the cavity. The thermostat will sense the loss of heat and compensate for it through additional burning; when one opens the oven door, he indirectly causes additional burning. This is a gram ha’avara which is rabbinically prohibited.

Normally one does not want the heating element to go back on if the oven is empty. Even though opening the oven door will cause the element to burn longer, this is an unintended action. On the contrary, it is a needless waste of gas or electricity. This is considered a psik reisha d’lo nicha lei. Although we do not allow a psik reisha d’lo nicha lei on a Torah prohibition, this action occurs indirectly as a grama and is only a rabbinic prohibition.11 Thus, when there are a combination of factors (e.g., a grama on a psik reisha d’lo nicha lei) it is permitted.

If one leaves food in the oven after the door has been opened, he obviously wants the oven to go back on. This is prohibited as a psik reisha d’nicha lei, as if one intended to cause the fire to burn longer. If one accidentally opens the oven door, all of the food must be removed and the oven door cannot be opened again during Shabbos.

Q. My oven and warming drawer have a delayed start timer feature. May I set it to turn on Shabbos morning and place the food to be heated there on Shabbos before the pre-determined time?

A. No. Food may not be placed in the oven on Shabbos.

Q. May I open my oven to remove food on Shabbos?

A. First, one must be sure that opening the oven door does not trigger a light, icon or electrical switch or flame to go on or off. In the case of convection ovens, opening the door may cause the circulating fan to go off. Even though these actions are not intended, they are prohibited as if there was intent since this is an automatic consequence. If opening the oven door does not automatically set off an electrical reaction, then one may do so in order to remove food on Shabbos, provided that all the food is removed at that time.

NOTE: The oven door is commonly designed with a plunger switch that turns on lights or icons as the door is opened. If this plunger switch is disabled, it may prevent any prohibited reactions. Some STAR-K Sabbath Mode ovens have a feature that disables all icons, lights or signals that allows the oven door to be opened on Shabbos and Yom Tov.

Q. May I use a warming drawer on Shabbos?

A. As discussed earlier, one may not put food into a warming drawer on Shabbos. Most warming drawers are regulated by a thermostat, which renders them halachically identical to a regular oven. When you open the drawer to place the food inside, you will cause the burner to go on and compensate for the heat loss that was created. By keeping food in the drawer, one is clearly desiring this extra heat. This is prohibited on Shabbos.12 If the food was placed in the drawer before Shabbos, a warming drawer must be completely emptied the first time it is opened.

A warming drawer with adjustable temperature settings that include temperatures over yad soledes (120°F) is like an oven, as it has the same restrictions as an oven and its controls must be covered. If the warming drawer’s settings are all below yad soledes then there is no gezeira (rabbinic prohibition) to cover the controls. However, one may not change the setting on Shabbos.

Q. Why is one allowed to push a button on the keypad of a Sabbath Mode oven on Yom Tov?

A. Pushing any button on an oven in Sabbath mode starts a process internal to the computer without any heat, light, sound, movement or anything tangible that can be perceived. This is not considered a melacha and is permitted on Yom Tov. When a melacha is finally accomplished, such as turning on the heating element in the oven, it is done through a grama (an indirect act) because there is a delay of 15-25 seconds before the heating elements can be activated. This grama is permitted on Yom Tov but not on Shabbos.

Q. Can one turn on a Sabbath Mode oven on Yom Tov or Shabbos?

A. No. This is because it directly causes the display to change, which is prohibited.

Q. Can I set the Time Bake feature on Yom Tov?

A. No. For those ovens that have the Time Bake feature included in the Sabbath Mode, it can be set only before Yom Tov. This will allow for one-time usage. Once the oven shuts off, it cannot be used again for the remainder of that Yom Tov. Time Bake mode may not be set on Yom Tov, and certainly not on Shabbos.

Q. May one turn off the stove or oven to conserve energy on Yom Tov?

A. No. One is only permitted to lower the setting when necessary to benefit food preparation for Yom Tov.

Q. May one lower the setting on a Sabbath Mode oven even when it is not for the benefit of the food?

A. Sabbath Mode ovens that are equipped with a delay may be lowered on Yom Tov. This is because the reaction of the oven in lowering the temperature is the result of a grama (indirect action). Extinguishing or lowering a flame is permitted on Yom Tov only when it is needed for food. However, the restriction applies where one directly performs the action of Kibuy. In this case, when the computer lowers the temperature after a pre-programmed delay in response to one’s instructions, it is called gram Kibuy and it is permitted.

Q. Can I open and close a standard oven door at any time on Yom Tov?

A. On Yom Tov, one may open and close the door of an oven in order to handle the food as needed, provided doing so does not cause a light or icon to go on as a direct result. On Shabbos, there is a problem with opening the oven door because it will cause additional burning in the oven. This is prohibited on Shabbos 13 but permitted on Yom Tov.

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