By Rabbi Sholom Ber Lepkivker, Rabbinic Coordinator
What are convection ovens?
Convection ovens (also known as “fan ovens”) are a fairly new addition to the kitchen, making their first appearance around 1914, compared to traditional ovens.
The idea behind the convection oven is that it provides an even circulation of hot air, so the product is baked and browned evenly (and not burnt on one side) and in less time than a traditional oven. There are some additional varieties of convection ovens, but they all use the same basic mechanism of a fan blowing hot air.
Convection ovens have the same basic kashrus requirements as a traditional oven – it should be dedicated to either meat or dairy, etc.1
What do I do if I want to kasher a convection oven?
When it comes to kashering any oven, one first needs to determine the kind of kashering that is required. This would depend on the size, durability and functions of the oven.
Assuming one is asking about a regular oven which also has the convention function: If you kasher the oven from real treif, for example if you purchased the oven from a non-Jew who most probably used it for things similar to pork, etc., the oven would require a full libun. This means that one would need to use a blow torch, unless the oven has a self-cleaning function that reaches a temperature of 500°C. If you are not kashering from treif; rather you need to change your milchig oven to meat or vice versa (in a permanent manner), which essentially means that the oven is already kosher, a libun kal would suffice. The oven needs to be completely clean and it’s best to make sure that it hasn’t been used for at least 24 hours. In the kashrus world the accepted temperature for a libun kal is around 287.7°C (550°F). The oven needs to be run at this temperature for at least 1 hour.
Convection microwaves and portable convection ovens, don’t usually have a self-cleaning option and probably won’t stand the intense heat of the blowtorch, so they generally cannot be kashered from treif. Kashering from meat to dairy (or vice versa) would be done the same way as with a full size convection oven. If the oven cannot reach the correct temperature (550°F), it’s better not to kasher at all and purchase a new oven.
1. See Kosher Spirit, Tishrei 5778.