Winter 2026

“I would like to purchase a countertop which can be kashered for Pesach. What should I buy?”

“I moved into a house, and the previous owner was not Jewish. Can I kasher the countertop?”

The answer to these questions and variations thereof depends on the material from which the countertop is made. We will begin by addressing which materials can be kashered and which cannot; then describe the kashering process; and finally, conclude with guidelines for countertops that cannot be kashered.

Countertop Materials

Kitchen countertops can be made from a host of different materials.  Some materials can be kashered, and some cannot. (See the chart in Fig. 1.)

With regard to stone countertops, there are two basic types:

► A natural stone slab – This is one large piece of natural stone. The slab is mined whole and left intact.

►  An engineered stone composite – This consists of stone fragments which have been pressed and glued together.

Rav Heinemann shlit”a paskens that a natural stone slab can be kashered, whereas an engineered stone composite cannot.

One who moves into a house and does not know whether the countertop is made from natural or engineered stone should contact a kitchen design expert and send him a photo of the countertop. A professional should be able to determine the material it is made from.

Type	Can Be Kashered According to STAR‑K	Notes
Caesarstone	No	This is an engineered composite.
Ceramic Tile	No
Concrete	No
Corian	No	This is made from a blend of roughly one-third acrylic polymer and two-thirds natural mineral.
Dolomite	Depends	If natural stone: Yes; If engineered composite: No
Enamel	No
Formica	No	This is a plastic laminate.
Granite	Depends	If natural stone: Yes; If engineered composite: No
Laminates	No	This is a plastic (e.g., Formica).
Marble	Depends	If natural stone: Yes; If engineered composite: No
Metal	Yes
Onyx	Depends	If natural stone: Yes; If engineered composite: No
Plastic	No
Porcelain	No
Quartz*	No	An engineered composite. (See NOTE)
Quartzite*	Yes	A natural stone. (See NOTE)
Silestone	No	An engineered composite.
Soapstone	Depends	If natural stone: Yes; If engineered composite: No
Wood	Depends	Wooden countertops may be kashered provided they are smooth and have no cracks or crevices.

Fig. 1: List of Countertops Materials and Their “Kasherability”

* NOTE: Quartzite vs. Quartz: Quartzite – is a natural stone that can be kashered. Quartz – is an engineered composite that cannot. These materials look the same, and the two terms often get mixed up. One purchasing a quartzite countertop should verify that he is getting a natural stone slab and not an engineered composite.

How to Kasher a Countertop

The countertop should be clean and not used for hot (i.e., above yad soledes, which is 120°) for the 24 hours before the kashering. 

1. Pour boiling water onto the countertop from a pot or kettle which has been heated on the fire.  
2. Move the kettle slowly, such that the stream of water directly hits every spot of the countertop.
3. Refill the kettle and heat the water as often as needed in order to accomplish this.

Note that this process is messy, as boiling water will spill over the sides of the countertop and onto your floor.[1]

Methods Requiring Professional Equipment

There are other ways to kasher countertops, but these require professional equipment and expertise and should not be attempted by a homeowner. These include:

► Steam Kashering

Igros Moshe (Y.D. 1:60) paskens that one cannot kasher with steam. Therefore, most steam machines cannot be used for kashering. However, Igros Moshe allows a steam machine to be used if it produces steam which condensates on the countertop surface into water, and the steam machine then heats the water until it is boiling hot. STAR-K has determined that steam machines sold in retail stores are not powerful enough to accomplish this and cannot be used for kashering. For this reason, one cannot kasher with steam unless he owns specialized equipment, which is fairly costly.

► Sanding

When hot non-kosher food is placed on a countertop, the non-kosher taste is only absorbed kedei klipah, meaning that it is not absorbed further than the thickness of a piece of paper. If that uppermost paper-thin layer of the countertop is physically removed, the countertop no longer needs kashering. This is true even when the countertop is made from material that cannot be kashered. Therefore, if the countertop material can be sanded, there is no need to kasher it. Doing so, however, is likely to ruin the countertop. A countertop should only be sanded by a trained professional.   

Dealing with Unkasherable Countertops

Managing a kitchen with an unkasherable countertop is actually very doable. Here are the basic guidelines:

During Pesach	Fully cover the countertops.
During the rest of the year	Cold food: may be placed directly on an unkashered countertop
	Hot cookware and dishes: should be placed on a trivet

If a hot utensil was inadvertently placed on an unkashered countertop, there is no need to kasher, provided the area where the underside of the utensil came into contact with the countertop was clean and dry. This is due to the halachic principle that ein kli oser kli b’lo rotev.

Food above the temperature of yad soledes should not be placed on an unkashered countertop. If that happened inadvertently, the hot food may be consumed provided that no non-kosher food above yad soledes had been placed on the countertop in the previous 24 hours.

For further halachic guidance, consult your rav.

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[1] An alternative method is to run an iron over hot water on the countertop as demonstrated in the video on the STAR-K website at https://www.star-k.org/videos?channel=benyomo. STAR-K takes no responsibility for the safety of this process or for any damage to the countertop.