How Do I Kasher My Granite Countertops for Pesach?

Granite countertops are made from a slab of stone. Shulchan Aruch (O.C.451:8) writes that stone can be kashered. The general rule in kashering is kbol’o kach polto (the way the material absorbed is the same way it needs to be kashered). Since the concern is that hot chametz might spill on the counter, it requires kashering with iruy, pouring boiling water over every area of the counter. The water cannot be poured directly on one area and allowed to flow down the counter, but rather one must pour on every spot directly from the kettle. Mishnah Berurah (451:114) adds that if hot bread might have been placed on the counter, it is not sufficient to kasher with iruy alone, but rather one must accompany the boiling water with a heated stone. Using a heated stone allows for a leniency as well. The boiling water need not hit directly on every spot, so long as the heated stone follows after the water. The stone will need to be reheated several times, so that it remains hotter than the boiling water. Granite counters can be kashered even though a sealant had been applied. The sealant is absorbed into the stone, and does not act as a chatzitza (barrier) to kashering. However, on a practical level, Rav Belsky, zt”l would recommend that countertops not be kashered but instead be covered, since it is difficult to do this correctly, safely and without flooding the kitchen.

The Gerald & Karin Feldhamer OU Kosher Halacha Yomis is dedicated to the memory of Rav Yisroel Belsky, zt”l, who served as halachic consultant for OU Kosher for more than 28 years; many of the responses in Halacha Yomis are based on the rulings of Rabbi Belsky. Subscribe to the Halacha Yomis daily email here.