How to keep food hot in an oven over Shabbos
1. What is the purpose of this guide?
The use of an oven on Shabbos and Yom Tov presents a number of halachic questions. Even if an oven is equipped with the ‘best’ Sabbath mode, the oven will not bypass the laws of cooking and warming on Shabbos. One must therefore be familiar with these laws before making any use of an oven on Shabbos.
In this guide we will discuss these laws of cooking and warming on Shabbos as they apply to common situations of oven usage in our kitchens.
Please also be aware that contemporary ovens are more likely than pastime ovens to react when the user opens or closes the door. Therefore, before using an oven, one must ensure that the oven is compliant with the laws of Shabbos. For information on this aspect of oven use, please read the guide ‘Introductions to ovens on Shabbos and Yom Tov’.
2. How can I use my oven on Shabbos?
At sunset of Friday afternoon, all food which will be left heating over Shabbos must be fully cooked. Alternatively, the fire on which the food is heating must be covered with a blech. This requirement is called גרופה וקטומה.
When using a hotplate or blech one may leave uncooked foods warming over Shabbos. However, since an oven’s heating element is deemed to be an exposed fire, this is not the case with regards to foods left in an oven.
Therefore, even when operating in Sabbath mode, all food left in the oven must be fully cooked before sunset.
3. Can I heat foods on Shabbos by putting them in the oven when on Sabbath mode?
In heating a cold food on Shabbos, the following rules should be noted:
- A cold liquid may not be heated on Shabbos
- An uncooked solid food may not be heated on Shabbos.
- A fully cooked cold solid food may not be heated by placing it on the fire even if the fire is covered (eg. a blech is in place or when using a hotplate).
- A fully cooked solid food may be heated by placing it on top of a full pot which is warming on the hob (where the fire is covered by a blech) or on an upturned empty tray or pan on the hotplate.
Foods may never be placed to warm in an oven on Shabbos. This remains the case even when ‘Sabbath mode’ is in operation. Therefore, all food must be placed in the oven already warm before the onset of Shabbos.
4. If I take food out of the oven can it be returned?
Returning a pot to the fire is viewed in a more lenient light than initially placing food on the fire. For this reason, as long as certain halachic criteria are met, it is possible to return a food directly to the covered fire and it is not necessary to place it on top of a pot.
According to many opinions, the permission to return a hot food to the fire is totally suspended in relation to an oven. No food may be returned at all to an oven on Shabbos. This is true even if the oven is operating in Sabbath mode.
5. How can one make use of an oven in ‘approved’ Sabbath mode?
When buying an oven with a reliable Sabbath mode, remember that no food can be placed inside to heat on Shabbos itself.
Instead, all foods must be fully cooked and placed warm in the oven from before Shabbos.
6. Do these same restrictions apply on Yom Tov as well?
On Yom Tov there is no prohibition to cook like there is on Shabbos. Therefore, one may use their oven freely on Yom Tov, with regards to the laws of cooking, and one may put in cold and uncooked food even on Yom tov itself.
The reader is reminded to make sure that their oven is Shabbos/Yom Tov compliant with regards to the opening and closing of the door and the general use of the oven. (To read more about the Shabbos/Yom Tov compliance of an oven please click here.)
7. What do I do if I have questions about this guide?
As always, if you require assistance, the ShailaText team of Rabbonim is available on 07403939613.
Questions can also be forwarded to technology@federation.org.uk.