The Halakhot of Stove and Oven Use on Shabbat and Yom Tov
Rabbi Meir Sendor
Our stoves and ovens get a lot of use throughout the month of Tishrei in preparing Yom Tov meals, in addition to our weekly Shabbat preparation. This is a good time to review the halakhot of oven and stove use on Yom Tov and Shabbat, and to correct some common misunderstandings when it comes to the use of ovens with the Sabbath Mode feature.
The Star-K Kashrut organization, pioneers together with appliance manufacturers in the development of the Sabbath Mode setting for ovens, acknowledges that the trade name for this feature is unfortunate and has led to misunderstandings, and has appealed to rabbis to help correct the problem. The real advantage of the Sabbath Mode feature is for Yom Tov, and even here it is subject to halakhic rules that define a very limited set of parameters for oven use.
Let me quote directly from warnings issued on the Star-K website:
The Sabbath Mode does not allow us to turn these appliances on or off on the Sabbath. The Sabbath Mode also does not 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…
Ovens with the Sabbath mode on will not shut off after twelve hours of continuous operation. In many cases this mode will prevent the oven light from going on/off as the door is opened/closed. In some models, however, the bulb must be unscrewed or the light left on for the entire period. No lights, digits, solenoids, fans, icons, tones or displays will be activated/modified in the normal operation of the oven.
For these Sabbath mode models, the set temperature can be raised or lowered on Yom Tov (but not on Shabbos) for cooking purposes at any time, because there is a built-in delay between the request for temperature change and its actual implementation.
The following rules apply to oven use, with or without the Sabbath Mode:
1. No adjustment to the temperature is permitted on Shabbos even in the Sabbath Mode.
2. All food must be fully cooked and placed in the oven before Shabbos. No food (cooked or non-cooked) may be placed in the oven on Shabbos to re-warm or cook. This is true regarding ovens, as well as warming drawers.
3. It is the opinion of Rabbi Heinemann that on Shabbos, for the thermostatically controlled oven that is running (as opposed to one shut off by timed bake), the door may be opened once at any time and all the food removed at that time. The oven may not be used any further for that Shabbos. [This refers all modern ovens, regular and Sabbath mode, and to food that is fully cooked that was placed in the oven before Shabbos to stay warm].
4. The controls of an oven that is left on for Shabbos (or part of a Shabbos with a timed bake) should be covered with something like a piece of aluminum foil. Caution: Please be careful not to cover the vents.
With these warnings and corrections from Star-K in mind, let’s review the rules of cooking and keeping food warm on Shabbat and Yom Tov, and how they apply to ovens and stove tops with the Shabbos Mode feature.
Shabbat. Halakhah permits the use of a stove to keep food warm on Shabbat. The active stove burner should be covered with a blech such as a sheet of steel or thick aluminum. The food should be fully-cooked and placed on the blech before Shabbat begins. When food is served, the pot or pan should be removed from the burner. If after serving you intend to replace the pot on the burner to continue to stay hot, you should have this intention in mind throughout the time in which the pot is off the burner. You should also keep your hand in contact with the pot handle at all times until it is returned to the burner. If the pot cover has been removed to serve food, the cover should be placed back on the pot before the pot is put back on the burner. One of the advantages of the Sabbath Mode is that it keeps stove burners and ovens of certain models from shutting off after 12 hours, so the stove can stay on for all Shabbat to keep food warm. The 12 hour shut-off is a safety feature and Sabbath Mode overrides this feature.
Certain foods may taste better if they have not been on the blech all Shabbat. It is possible to warm up foods on Shabbat day, but only under the following conditions. The food to be warmed up must be fully cooked and it must be dry. Dry foods include kugels that have no residual liquid, plain pasta with no sauce, baked potatoes and baked, roasted or fried chicken with no sauce or gravy. The food to be warmed up must be on the blech as Shabbat comes in and only removed from the blech some time after nightfall. The food to be warmed up cannot be placed directly on the blech nor in the oven. It can be placed only on a covered pot that is on the blech, including on top of an active crock-pot or slow cooker. It can also be placed on a Mayim Blech®, which simulates a pot on top of a blech.
Yom Tov. On Yom Tov we are permitted to cook food on an already-lit or active burner or in an oven that is on. We are not permitted to ignite a fire or extinguish a fire, so we are also not permitted to turn on or off an electric stove or oven, or a digitally-controlled gas oven or stove. We are permitted to increase an already lit flame, but not decrease it. This means that on Yom Tov, even though stove and oven use is permissible for cooking, there are limits to the way we can use the oven and stove.
If you have an old gas stove and oven, the rules for cooking on Yom Tov are straightforward. The stove and oven should be lit before Yom Tov, on a low flame. When you are ready to cook, you can increase the size of the flame for the sake of effective cooking. When you are finished cooking that food item, the flame cannot be lowered. But if you want to cook something else, and the best flame for that item would be a low flame, you can place that item on the burner or in the oven and lower the flame and leave it there. Your cooking schedule should be planned such that the last thing you cook requires a low flame. So for instance, the last thing to heat can be hot water for tea or coffee, which is typically prepared by turning the flame to simmer after the water has been brought to a boil.
Some old electric stoves and ovens can be more difficult to use on Yom Tov. If the rheostat that controls temperature adjusts continuously, it can be used like a gas stove or oven to turn temperature up and, when justified by the needs of the cooking, down. If the stove burner or oven is adjusted to low, medium or high levels by knobs or buttons that activate separate circuits, the stove or oven cannot be adjusted on Yom Tov, since turning the knob or pressing the button connects a new circuit, igniting it, and disconnects the old one, extinguishing it. So you must choose one setting and keep it there.
The new digitally-controlled stoves that don’t have Sabbath Mode, whether gas or electric, are like those old electric stoves with separate circuits for every temperature selection, so they cannot be adjusted on Yom Tov. One of the main purposes of the Sabbath Mode feature is to allow some adjustment of temperature for digital controls. By using random-delay relays and disabling the digital display, the Sabbath Mode allows you, on Yom Tov not on Shabbat, to raise the cooking temperature or to lower it according to the usual rules for the old gas ovens and stoves, stated above: you can always raise temperature for cooking, but you can lower temperature only if it enhances the cooking. The Sabbath Mode also overrides the 12 hour safety shut-off and in some models keeps oven lights off.
There are further details and complexities in the halakhot of cooking and keeping food warm on Yom Tov and Shabbat for various modern appliances. If you have questions please email me at meir@sendor.org or call me at 781-784-5391.
Shanah Tovah!
Rabbi Meir Sendor