The Modern Kitchen

OU Kosher Staff


Glossary of Terms

Libun Gamur – Burning

Hagalah – Boiling

Iruy Kli Rishon – Poured Boiling Water

Even Melubenet – Heated Stone


SILVERWARE, POTS & OTHER SMALL ITEMS: Hagalah (boiling in water)

Rolled lips, seams or cracks, which cannot be cleaned, will require torching of those areas. Utensils should be immersed one at a time into a pot of boiling water that is on the fire. Water should be allowed to return to a boil before the next item is placed in the pot. The pot can be non-Passover, provided it is clean, has not been used for 24 hours, and water is first boiled in the pot and discarded. Larger items can be submerged in the water one part at a time. Utensils should then be rinsed in cold water.

KEURIG COFFEE MAKER: Hagalah or Iruy (pouring boiling water) (for those who kasher plastic)

The coffee maker must be cleaned well and not used for 24 hours. Remove K-cup holder and perform hagalahor iruy on K-cup holder. Run a Kosher for Passover K-cup in the machine (this will kasher the top pin).

HOT WATER URN, WATER COOLER: Iruy (pouring boiling water)

Urn only used for heating water: Run hot water through the water tap for 10 seconds, while pouring boiling water from a kettle over the water tap.

Urn also used to warm food (e.g. to warm challah): Not recommended. Must be put away for the holiday.

Water Cooler In addition to pouring boiling water over tap, replace water bottle.

ELECTRIC MIXER: Not recommended

Because of the difficulty in cleaning out the housing of the mixer from fine particles of flour, one should not use their year-round mixer on Pesach. The mixer blades, though, can be cleaned and koshered with hagalah.

GAS STOVETOP: Libun (burning) & Cover

The stovetop surface and grates should be cleaned well and not used for 24 hours.

The stovetop surface should be covered with foil. The stovetop grates can be replaced or they should be burned out in the oven @ 550° F for one hour.

ELECTRIC STOVETOP: Libun (burning) & Cover

The stovetop surface should be cleaned well and covered with foil. The burners should be turned on until they glow red.

GLASS STOVETOP: Cannot be kashered & must be covered*

The stovetop surface should be cleaned well and not used for 24 hours.

During Pesach pots should not be placed directly on the stove surface, but rather an aluminum (or other metal) disk should be placed directly under the pot.

*The entire glass top surface should not be covered as this might cause it to overheat and crack.

METAL TEA KETTLE: Hagalah (boiling in water)

The same treatment as for pots applies here. Although it is uncommon for anything but water to be put into a tea kettle, nevertheless it must be kashered. Tea kettles often sit on the stove, and it is common for them to get spritzed with hot food.

SELF-CLEAN OVENS: Libun (burning)

Remove any visible food. Complete self-cleaning cycle with racks in place.


Clean all surfaces (walls, floor, doors and racks) thoroughly with a caustic cleanser (e.g. Easy Off). Pay special attention to thermostat, oven window, and edges of the oven chamber. Black discoloration that is flush with the metal need not be removed. Oven should not be used for 24 hours. Place racks in the oven and turn the oven to broil (highest heat) for 60 minutes. A broiler pan that comes in direct contact with food should not be used.

Note: The method of koshering described above is based on the ruling of Rav Aharon Kotler zt’l. However, Rav Moshe Feinstein zt’l ruled that the oven must either be koshered with a blow torch, or an insert should be placed in the oven. Consult your rabbi for guidance. 

WARMING DRAWERS: Libun (burning)

Typically warming drawers do not get to libun kal temperature. Therefore, unless one is experienced in koshering with a torch, warming drawers are not recommended for use on Pesach.

STAINLESS STEEL SINK:  Iruy (pouring boiling water)

Remove drain. [It is recommended that the drain be replaced. If this is difficult, it may be used if the drain has large holes that can be completely scrubbed clean]. 

It is preferable to kashar a sink by pouring boiling water in conjunction with an even melubenet (a heated stone). In lieu of koshering with a heated stone, some will place a rack on the bottom of the sink, or use a sink insert.

CERAMIC SINK: Cannot be kashered and must be covered

The sink should not be used with hot water for 24 hours. The sink should be completely clean and dry.

The sink should be covered with layers of contact paper or foil; it is best to purchase a sink insert.

MICROWAVES: Hagalah (boiling in water) (for those who kasher plastic)

The microwave must be cleaned well and not used for 24 hours. Glass turntable should be removed and replaced with new kosher for Passover surface. A styrofoam cup should be filled with water and boiled in the microwave for 10 minutes. The cup should be refilled and moved to another spot and the process repeated for 10 more minutes. Cardboard or contact paper should be taped over the glass window pane for the duration of Pesach. 

THE SINK FAUCET (INCLUDING INSTANT HOT): Iruy (pouring boiling water)

Detach any filters or nozzles.


It is preferable to kasher a countertop by pouring boiling water in conjunction with an even melubenet. There are different opinions as to whether formica (or plastic) countertops can be koshered for Pesach.

CERAMIC TILE COUNTERTOPS: Cannot be kashered & must be covered

The counter should be covered with a water-resistant covering.

DISHWASHERS: Hagalah (boiling in water) Kashering of dishwashers is a complicated process and should only be done in consultation with a halachic authority.


These areas should be thoroughly cleaned, paying special attention to the edges where crumbs may get trapped. The surfaces should be lined with paper or plastic. 

Note: Refrigerators and freezers will operate more efficiently if holes are poked in the lining to allow air flow. 


The tray should be covered with contact paper. The seat, legs and bars should be wiped down with a soapy rag.

TABLES: Covered

Although wooden tables can be kashered, the common custom is to clean tables well and then cover them.

TABLECLOTHS, KITCHEN GLOVES, APRONS & OTHER FABRIC ITEMS: Wash Fabric items can be koshered by washing them with detergent in a washing machine set on “hot.” Items should be checked to make sure no pieces of food remain attached.

OU Kosher Staff

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