Myth #1: Every oven that has a Sabbath mode is certified by STAR-K.
Fact: An oven that has a Sabbath mode may or may not be certified by STAR-K. In fact, the same company may manufacture some ovens which have a STAR-K certified Sabbath mode and other ovens with a Sabbath mode which do not have any certification at all. One can verify an oven is STAR-K certified by consulting the oven’s manual, calling us (410-484-4110), or looking at the list on STAR-K’s website (www.star-k.org/appliances).
Reason: STAR-K does not own the copyright to the term “Sabbath mode” and cannot prevent a company from using those words.
Myth #2: A person who does not intend to raise or lower the oven temperature may use any oven on Shabbos and Yom Tov, and there is no reason to use an oven which has a STAR-K Sabbath mode.
Fact: When using an oven on Shabbos or Yom Tov, it may be necessary to put it into STAR-K Sabbath mode even if the temperature will not be adjusted.
Reason: Even if the temperature will not be adjusted, an oven needs to be put into STAR-K Sabbath mode in order to disable the 12 hour automatic shut-off and to prevent any lights or icons from going on or off.
Myth #3: When an oven is in STAR-K Sabbath mode, it may be used on Shabbos in the same way that it is used every other day of the week.
Fact: When an oven is in STAR-K Sabbath mode, the oven temperature may neither be adjusted nor turned on or off on Shabbos. Putting an oven into STAR-K Sabbath mode does not permit these activities on Shabbos.
Reason: The thermostatic controls are not disabled by putting the oven into STAR-K Sabbath mode. Therefore, changing the oven temperature will affect when the flame goes on and off. Even if there is no immediate change, causing a flame to go on or off after a time delay is generally forbidden on Shabbos.1
Myth #4: When an oven is in STAR-K Sabbath mode, it may be used on Yom Tov in the same way that it is used every other day of the week.
Fact: When an oven is in STAR-K Sabbath mode, the temperature may be raised on Yom Tov as needed and may be lowered in order to prevent food from getting burnt or ruined. The temperature should not be lowered on Yom Tov if it is not necessary, and the oven may not be turned on or off.
Reason: When an oven is in STAR-K Sabbath mode, changing the temperature setting will not result in any immediate change of temperature. Rather, the oven temperature will change after a short time delay. Causing a change of temperature after a time delay is permissible on Yom Tov.2 It would theoretically be possible to create various electronic devices with such a time delay feature, such as a Yom Tov telephone and a Yom Tov radio. However, that would denigrate the honor of Yom Tov. The reason that STAR-K Sabbath mode ovens do not denigrate the honor of Yom Tov is due to the fact that the time delay feature is merely being used to allow contemporary ovens to be operated in the same way that ovens were used 50 years ago on Yom Tov. Gas ovens used to have a pilot light, and the halacha is that the temperature of such an oven may be raised on Yom Tov as needed and lowered in order to prevent food from getting burnt or ruined.3 A STAR-K certified Sabbath mode oven should be treated in the same manner.
Myth #5: When an oven is in STAR-K Sabbath mode during Shabbos, the oven door may be opened in order to remove some food, then closed, and subsequently opened once again in order to remove more food.
Fact: On Shabbos, when an oven is in STAR-K Sabbath mode and the oven door is opened, all of the food in the oven must be removed before closing the door. On Yom Tov, it is not necessary to remove all of the food when the oven door is opened.
Reason: When the oven door is opened, the thermostat will register the change in temperature and cause the flame to go on sooner than usual. As mentioned above, causing a flame to go on after a time delay is generally forbidden on Shabbos. However, if all of the food is removed from the oven then the flame which goes on in the now empty oven is not beneficial or wanted. An unwanted melacha which occurs after a time delay is permitted on Shabbos.4
Myth #6: When an oven is in STAR-K Sabbath mode, cold fully-cooked food may be put into the oven on Shabbos.
Fact: Cold fully cooked food may not be put into an oven on Shabbos, even when the oven is in STAR-K Sabbath mode.
Reason: As mentioned above, when an oven is in STAR-K Sabbath mode and the oven door is opened on Shabbos, all of the food in the oven must be removed. For the same reason, no additional food can be placed in the oven. Additionally, if the food had not previously been on the fire on Shabbos, Chazal forbade putting even fully cooked food onto a fire on Shabbos.5
Myth #7: When an oven is in STAR-K Sabbath mode, opening and closing the door does not cause the oven light to go on or off.
Fact: In some ovens, if the oven light is off it will automatically go on when the door is opened even if the oven is in STAR-K Sabbath mode. It is necessary to manually turn on the oven light before Shabbos so that the light stays on for the whole Shabbos. This is clearly explained in the manual of any oven which has this feature.
Reason: Programming an oven with a Sabbath mode feature will affect the circuitry which runs the oven. However, the oven light may have its own circuitry which is independent from the circuitry that runs the oven. Therefore, the Sabbath mode feature may not affect the oven light.
Myth #8: Some ovens have a feature which automatically turns the flame off immediately when the oven door is opened, and turns the flame back on when the oven door is closed. Putting the oven in STAR-K Sabbath mode completely disables this feature.
Fact: Some ovens are designed so that the flame is extinguished immediately when the oven door is opened. Putting an oven in STAR-K Sabbath mode delays this automatic shut-off, but does not disable it completely. The STAR-K Sabbath mode also delays the reigniting of the flame after the oven door is closed, but does not disable it completely. This delayed shut-off and resumption of the flame is not of halachic consequence.
Reason: Causing a flame to shut off after a time delay is permitted on Shabbos if the consumer does not care whether or not that flame is extinguished.6 Furthermore, since all food must be removed from an oven once the door is opened on Shabbos, the consumer will have no further benefit from the flame when it reignites. Therefore, the delayed extinguishing of the flame when the oven door is opened and subsequent delayed resumption of the flame when the door is closed are permissible on Shabbos.
Myth #9: Some STAR-K certified ovens come with a cast-iron griddle attachment that is seasoned with a STAR-K kosher certified seasoning.
Fact: The company that produces this oven griddle currently uses kosher vegetable oil for the seasoning. However, as stated in the manuals for these ovens, STAR-K does not give a hashgacha on the seasoning process and advises the purchaser to kasher the griddle before use. This can be accomplished by washing the griddle with soap in lukewarm water and then putting it into the oven at 550° for 45 minutes.
Reason: STAR-K does not have a contract to provide hashgacha for the seasoning of these oven griddles.
Myth #10: STAR-K certification of Sabbath mode ovens has proceeded without incident. If a person notices anything surprising about his STAR-K Sabbath mode oven, he need not contact STAR-K.
Fact: Certain ovens have recently been redesigned in a manner that compromises the Sabbath mode. STAR-K has recently issued alerts on certain models of Bosch, LG and Samsung ovens. These alerts are available at www.star-k.org/sabbath-mode-updates. If you have any questions or concerns about a STAR-K Sabbath mode oven, please contact us.
Reason: Oversights do happen, and consumers are requested to contact us if they see anything unusual about any STAR-K certified product. STAR-K appreciates it when people call with information.
1.רמ”א או”ח סי’ שלד סעי’ כב וביה”ל שם ד”ה דגרם
2.עי’ בשו”ע או”ח סי’ תקיד סעי’ ג ומ”ב שם ס”ק כה ושעה”צ שם ס”ק לא
3.עי’ בשו”ע או”ח סי’ תקז סעי’ ד וסי’ תקיא סעי’ א ומ”ב שם ס”ק א
4.עי’ במ”ב סי’ שכ ס”ק נג דפסיק רישא דלא ניחא ליה אינו אסור אלא מדרבנן, ועי’ בשו”ת מנחת שלמה ח”א סי’ י’ שגרמא על איסור דרבנן מותר בשבת
5.שו”ע שם סי’ רנג סעי’ ב
6.כנ”ל אות 4