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Oven Kashrus: For Yom Tov Use
Rabbi Avrohom Mushell, Star-K Kashrus Administrator

Yom Tov celebrations could never be complete without the piping hot delicacies that have become traditional through the generations. However the kosher homemaker must be well educated to know how to prepare Yom Tov meals without fear of transgression.

When stating the prohibition of work on Shabbos the Torah writes, “Do not do any melacha.”
1 This prohibition applies to melachah done for food preparation as well as for other non-food purposes. In stating the prohibition of melacha on Yom Tov the Torah writes, “You shall not do laborious work.”2 In addition, when giving the initial command about the Yom Tov of Pesach the Torah writes, “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 and meleches hana’ah. Meleches hana’ah is work done for food and similar necessary pleasures. Where the Torah commands us about the laws of Pesach, the term meleches avodah is not used in the prohibition. However, the Torah immediately includes the clause allowing melachah 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 done before Yom Tov with the same result, may be done 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 done for bulk processing of food, i.e. harvesting and grinding, are also prohibited. We commonly associate those melachos done in the processing of bread from the kneading of the dough and onward as permitted on Yom Tov and those processes before kneading i.e. sifting and grinding, as prohibited.

The focus of this article is primarily with the melachos associated with cooking on Yom Tov: cooking, burning of a flame and extinguishing a flame.

It is important to note that even those melachos that may be done for food preparation, or other Yom Tov necessities, may only be done with the intent that the benefit of this action will be derived 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 Tov for consumption on the second day of Yom Tov. This is because the second day is a holiday only by Rabbinic law. Therefore one must be sure not to do any melacha for the second day until the first day has passed and the next night has begun.3

When Yom Tov falls on a Friday, one may only cook for Shabbos if he had already prepared some food for use on Shabbos, before Yom Tov. This food which is set aside is called eruv tavshilin.4

With this knowledge in mind let’s take a look at what we are doing when we set the knobs of our ovens and cooktops and see how these rules apply.

Electric Cooktop

Turning on an electric stovetop to warm food will initiate the flow of electricity to the burner. The halachic authorities have determined that electricity used as heat or light is considered fire. Therefore by turning on the burner one is creating a new fire. This action could just as well have been done before Yom Tov and is prohibited because of molid. Turning the dial on your electric stovetop may also initiate a light or icon on a control panel which would otherwise be off. This may be a transgression of kosev, writing, as well as molid. Even when the electric burner was left on from before Yom Tov, if one wishes to adjust the temperature of the burner there is also reason for concern. This is because, as a rule, one does not know if there is electric current running to the element at the time they wish to make the adjustment. Even when there is an indicator light showing that a burner is on, this may not be an indication that electricity is flowing to the burner at that moment. Rather it is indicating that the element is set to maintain the desired setting which it will maintain by going on and off at pre-determined intervals. As a result when one adjusts the temperature upward on Yom Tov they may be initiating the flow of electricity at a time that it was otherwise not flowing. As mentioned earlier, this would be prohibited because of molid.

To circumvent this prohibition, an electrician can install an indicator light which is attached to the actual flow of electricity to the burner.5 This will indicate when there is current flowing to the burner. When there is electricity 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 is the melacha of kibui. Lowering the heat setting of a stove on Yom Tov may be associated with the melacha of kibui. Therefore, this can only be done when it is for the benefit of the food, so that it will remain warm but not burn. One may not turn the burner off completely. However, if there is an 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: Stovetops that come with the Sabbath mode ovens have not been engineered to allow the adjustment of the stovetop temperature. The stovetop must be handled like that of a conventional oven 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 one placing or removing a pot on the cooking surface and cannot be used on Shabbos or Yom Tov.

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 they may turn on their stovetop on Yom Tov without concern that they are initiating a flame. Due to safety concerns the old pilot flames have, for the most part, been phased out. Instead, cooktops have been fitted with electronic igniters which spark at the base of the burner to ignite the flame. This is prohibited on Yom Tov. One may only turn on a burner if they can do so without causing the electric igniters to go on. If it is possible to turn on the gas flow without starting the electric igniter, the burner may be started by holding a pre-existing flame (from a candle or a match lit from another burner) to the burner when turning on the gas. The easiest option would be to leave the burner on from before Yom Tov. It goes without saying that one may increase an existing flame on Yom Tov when it is necessary for food preparation.

As is the case with an electric stovetop, one can only lower the flame on a gas burner when this is done 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.

Electric Ovens

As with cooktops, one is prohibited from directly initiating a fire or heat to an electric coil because of the prohibition of molid. If the oven was left on from 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. Also, one may not cause a light or icon to go on. If one has an indicator light that 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, lowering the temperature can only be done if it is necessary for the Yom Tov’s food and where you will not be turning off a light or icon. If there is an indicator light cycling when power flows to the oven, one may lower the oven 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 with a random delay. This feature allows one to raise 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 to change. These “instructions” are being left for the computer to read at random intervals. The computer will then follow the “instruction” to raise the temperature. Therefore, this action is only causing a grama, an indirect action, which in turn will cause the temperature to be raised. Even in these ovens, it is better to lower the temperature only when necessary for food preparation or your enjoyment of Yom Tov. (Other features of Sabbath mode ovens are discussed further in this article.)

Gas Ovens

Older ovens used to be ignited with a pilot light. This is a small flame from which the oven drew its fire when turned on. In halachic terms, this allowed the user to turn them on, on Yom Tov without a question of transgressing the prohibition of molid. As with the gas cooktops, new ovens are equipped with electric igniters, most commonly an electric igniter called a glow plug. When turning on the oven, the power to the glow plug is initiated. When the glow plug is hot enough the gas will begin to flow and start 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 will restart the glow plug which in turn restarts the gas to bring the chamber back to the required temperature. Because one may not directly initiate the flow of electricity to the glow plug on Yom Tov, he must turn the oven on before Yom Tov. When raising the temperature on the oven on Yom Tov, one must be sure that they are not initiating electric current to the glow plug. Therefore, if one sees the glow plug glowing (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 for the benefit of the food. It is important to note that some ovens will give a digital readout of the temperature when raised or lowered. This would pose a halachic question of writing and erasing, both of which are prohibited acts on Yom Tov.

Sabbath Mode Ovens
(The Following Applies to Yom Tov Only)

Sabbath mode ovens are designed to bypass many of the practical and halachic problems posed by the modern oven. For the Sabbath mode ovens with the random delay feature, one may raise or lower the temperature of the oven without concern for the heating element or glow plug. This is because the computer does not directly react to the change in settings. The oven will randomly look to the setting and adjust the temperature. This means that turning on the heating element or glow plug is only an indirect result of your action (grama). Therefore, since a grama is permitted on Yom Tov one may actually adjust the temperature. For the Sabbath mode ovens without the random delay, 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

Another issue is that some ovens can be programmed to turn off at a preset time. This feature is known as timed bake. In many models, when the time has elapsed and the oven shuts off, it will sound a bell or buzzer or display a readout (such as the word “end”) to indicate that the oven is off. On some models this buzzer or display will continue until it is manually turned off or until the door is opened, which is not permitted on Yom Tov. On those Sabbath mode models that include the timed bake feature, the buzzer or readout is eliminated. (Please note that once the timed bake goes off, the oven cannot be used again for that Yom Tov.)

As a safety feature new ovens are designed to shut off after being on for twelve hours. Although this safety feature is very important, it creates a problem when preparing food for the daytime meal which is more than twelve hours after the onset of Yom Tov. For all types of Sabbath mode ovens, the twelve hour cutoff is bypassed.

In Sabbath mode ovens, the door plunger switch is disabled so that it will not directly cause any electronic reaction.

The oven cavity light for some Sabbath mode ovens will remain on or off, depending on how Sabbath mode was entered. For other Sabbath mode ovens, the light must be turned on at the control panel before entering the Sabbath mode, or the bulb must be unscrewed.

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 appliance section of our website at www.star-k.org to see which features are available on your model, or contact our office at 410-484-4110.7

The following are some commonly asked questions about oven and stovetop use on Yom Tov:
  1. Why is one allowed to push a button on the keypad of a Sabbath mode oven on Yom Tov?
    Pushing a button on an oven, when in Sabbath mode, on Yom Tov that starts a process internal to the computer without any heat, light, sound, movement or anything tangible that can be perceived, is not considered a melacha and is permitted on Yom Tov. When a melacha is finally accomplished, namely turning on the heating element in the oven, it is accomplished through a grama, (an indirect act because there is a random delay of between 15 and 25 seconds before the heating elements can be activated). This grama is permitted on Yom Tov, but not on Shabbos.
  2. Can one turn on a Sabbath mode oven on Yom Tov or Shabbos?
    Not on Yom Tov, and certainly not on Shabbos. This is because it directly causes the display to change which is prohibited.
  3. Can I set the timed bake feature on Yom Tov?
    For those ovens that have the timed bake feature included in the Sabbath mode, it can only be set from before Yom Tov. This will allow for a one time usage. Once the oven shuts off, it cannot be used again for that Yom Tov. One may not set the timed bake on Yom Tov (and certainly not on Shabbos).
  4. May one turn off their stove or oven to conserve energy on Yom Tov?
    No. One is permitted to lower the setting only when it is necessary for the preparation of the Yom Tov’s food.
  5. May one lower the setting on a Sabbath Mode oven even when it is not for the benefit of the food?
    Those Sabbath Mode ovens that are equipped with a random delay may be lowered on Yom Tov. This is because the random delay makes the reaction of the oven to lower the temperature a grama (indirect action). Although we permit extinguishing or lowering a flame only where it is needed for food, this applies where one does the action. Here, where the computer will lower the temperature later on as a reaction to your instructions, it is called gram kibui and it is permitted.
  6. Can I open and close a standard oven door at any time on Yom Tov?
    One may open and close the door of an oven on Yom Tov to process the food as needed if this does not cause a light or icon to go on directly because the door was opened. On Shabbos there is a problem with opening the door because it will cause additional burning in the oven. This is prohibited on Shabbos8 but permitted on Yom Tov.
  7. Must I wait until I see the glow plug glowing to open the door to my gas oven on Yom Tov?
    As a rule the oven will not immediately go on because of the reduction of heat created by your opening of the door. Therefore, even though the oven will eventually go on because its door was opened, this is not a direct result of your action. The additional burning is permitted on Yom Tov.

    Regarding raising the temperature of a gas oven on Yom Tov, one may not do so unless they know that the glow plug is glowing and the display will not change. This is because raising the temperature setting will directly cause the glow plug to go on if it is otherwise off, creating a problem of molid.
    However, if the oven is cerified with sabbath mode that has a random delay feature built in, and this was initiated before Yom Tov, one may adjust the temperature on Yom Tov.

Footnotes:

1. Shmos 20:9, D’varim 5:13

2. Vayikra 23:7

3. We consider it to be right after tzeis hakochavim.

4. The eruv should consist of a cooked and a baked food. Each food type should be a minimum of a kezayis (an average egg). A blessing and statement are recited as these foods are set aside before Yom Tov. By setting aside this food for use on Shabbos we are in essence saying that we have some food prepared for Shabbos. Therefore, that which we cook on Yom Tov for Shabbos is only to add to this mix of prepared food for Shabbos. In addition, it is best to cook early on a Friday Yom Tov, so that the food for Shabbos is ready on Yom Tov. This way you are also saying that the food is for Yom Tov, and if you would have visitors on Friday, this food could be served to them.

5. Please note that this may nullify a warranty.

6. Check the appliance section of our website at www.star-k.org or contact our office at 410-484-4110 to determine if your model has the random delay.

7. Please be aware that some companies advertise their ovens as having a Sabbath mode where in actuality, the only feature that the oven has is the twelve hour cutoff override. If it does encompass more than the twelve hour cutoff override, check to make sure there is a competent halachic authority behind the Sabbath mode to endorse it.

8. On Shabbos, while the oven is operating, the door may be opened once, all the food removed, and then closed. For further information about oven usage on Shabbos, see “Oven Kashrus: For Shabbos Use” on our website at www.star-k.org.



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