Introduction to ovens on Shabbos and Yom Tov

1. What is the purpose of this guide?

This guide has set out to clarify the problems inherent in the use of ovens for the Shabbos-observant consumer. We will clarify that even models which carry a ‘Sabbath mode’ feature are not guaranteed to be compliant with halachic requirements. We will explore the options available for those ovens which do not carry an approved ‘Sabbath mode’, and we will direct the householder towards ways to assess whether their oven can be used on Shabbos. 

2. What are the potential concerns with the use of an oven on shabbos and yom tov?

The following is a list of the issues which an oven can present in its Shabbos use; different models can have some or all of the following problems:

• Light and fan turn on or off when door opens or closes

• Writing on LED display screen appears or changes when door is opened

• When oven is operating, the heating element may switch off when the door is opened. The user will not be able to detect this.

• Heating element reignites when door closes. The user will not be able to detect this.

• Thermostatic control of the oven means that heating element comes on earlier than it would have because of the introduction of cold air to the oven cavity.

3. What is ‘sabbath mode’ in an oven?

When manufactured with input from a competent halachic authority, an oven working in ‘Sabbath mode’ is truly ‘Sabbath friendly’ as it complies with the laws of Shabbos. This is achieved by neutralising all of the direct and indirect effects the opening and closing of the oven door has on appliance activity, which allows one to access food which is heating in the oven.

In all cases, the food must have been placed in the oven before Shabbos, as discussed in-depth in our guide ‘How to keep food hot in an oven on Shabbos’.

This mode also addresses issues related to convenience and technical design. Amongst them is an ‘auto cut off’ feature – a safety feature designed to lower the risk of fires – which halts oven activity after a period of time. This would stop one from running the oven for longer periods, making Yom Tov cooking difficult. To allow for the convenience of Yom Tov cooking, the oven continues to run for up to 72 hours, but at a relatively low temperature.

In the case of ovens which are not manufactured under supervision, you should not use the oven unless it has been thoroughly investigated. As a rule, the simpler and older models are more likely to meet our criteria than the more recent models.

4. Why does ‘sabbath mode’ need a hechsher?

When designed under Rabbinic supervision, the mode will have dealt with all relevant issues. When input is lacking, not all issues are necessarily addressed.

Taken as an example, one company told us that, even when running in ‘Sabbath mode’, when the door of their oven opens, the power supply to the heating element will be immediately shut. When questioned, the company told us that they do not claim their mode to be halachically compliant with the laws of Sabbath. Use of the term Sabbath mode is certainly misleading in this context.

Members of the public are advised to research the model they are buying, and where necessary, to resort to other methods of heating food.

5. Which ovens have been certified or approved by Kehillas / FedTech, and what are their usage instructions?

Please click here for ovens which have been certified or approved by Kehillas/FedTech. Each device has its own usage instructions. Read carefully!

6. Is there any permitted way to make use of an oven which does not have a Hechsher?

In the case of ovens which are not manufactured under supervision, you should not use the oven unless it has been thoroughly investigated. As a rule, the simpler and older models are more likely to meet our criteria than the more recent models. However, there still are a number of ways to use an oven, even without a Hechsher. Please click here for a guide on how to test and use an oven.

If you have any queries regarding an appliance please don’t hesitate to contact us, and we will try to provide assistance where possible. This will also help us expand our facility. Please email all such queries to technology@federation.org.uk.

7. What else should I read about ovens?

It is imperative that when using ovens on Shabbos, members of the public are aware that food may not be inserted into them on Shabbos. Click here to read our guide on how to keep food hot in an oven over Shabbos.

You may also find it useful to refresh your knowledge on how to keep your oven kosher, click here to read our guide on this topic.

8. 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.