Introduction
Koshering an oven that has been used for non-kosher (treif) purposes is an important task that requires attention to detail and adherence to halachic rules.
In this guide, we will outline the steps necessary to kosher the oven thoroughly and professionally.
Important Notes Before the Kashering
– You must wait 24 hours from the last use of the oven.
– It is important to ensure that the oven is completely free of any food residues.
– It is recommended to consult with a rabbi regarding special cases or doubts.
How it’s done
According to most Rabanim/Poskim, a modern oven is considered an oven that is used by fire and therefore requires a severe libun (purification by fire). However, there are those who are lenient with modern ovens regarding a light libun for two reasons:
1. Most of the usage is through a ”Kli Sheini”/secondary tool (templates).
2. Sweat and odor are less absorbed by the coated walls.
Definition of Types of Libun/burning
Libun Chamur: Heating until sparks fly from it or the straw burns from the other side Libun Kal: Heating to the maximum temperature of the oven (usually 250-300 degrees Celsius)
How it’s done
1. Ideally: a severe libun should be performed
2. Special cases: Some are Meikel/lenient and say Libun Kal/Light burning can be permitted in modern ovens, particularly: – In an oven that is mostly used with trays and When the oven is coated with enamel or a similar material
How it’s done
Stage 1: Thorough Cleaning
1. Disassembling all the removable parts from the oven
2. Thorough cleaning of all parts of the oven with detergent
3. Removing all the grease and dirt that’s stuck to the sides of the oven
4. Special cleaning of the grooves and corners
5. Thorough washing and removal of detergent residues.
Stage 2: Waiting
– A 24-hour wait from the last use- Ensuring the oven remains clean and dry
Stage 3: Performing the Libun
First option
Libun Chamur:
– Using a special burner until there are sparks. In our times, many times there are no sparks, due to changes in the production of utensils.
– It is recommended to consult with an expert.
Second option:
Libun Kal:
– Heating the oven to maximum temperature
– Leaving the oven at this temperature for at least two hours
– Ensuring that all parts of the oven reach the maximum temperature
Stage 4: Treatment of the accompanying parts
– Templates: Libun Chamur or purchase of new ones
– oven grids :Libun Chamur
– Buttons and tracks: thorough cleaning.
Special Cases
Pyrolytic oven
– The activation of the self-cleaning program is considered Libun Chamur.
– It should be activated after thorough cleaning.
– Program time: According to the manufacturer’s instructions (usually about 4 hours)
Double-chamber oven
– Koshering each cell separately
– Ensuring there is no steam transfer between the cells
– In case of doubt, consult a rabbi
Recommendations for Maintaining Kashrut
1. Marking the oven as dairy or meat
2. Maintaining separate templates
3. Periodic inspection of the oven’s opacity
Summary
Koshering an oven is a significant process that requires strict adherence to halachic details. Ideally, a thorough libun (purification by fire) should be performed, but there are authorities who are lenient with modern ovens and allow a lighter libun. In any case of doubt, it is important to consult a qualified rabbi.
Nachman Harris. Kosher Expert.
Available for any of your questions
