By Rabbi Yair Hoffman

Silgranit is a popular trend in kitchen sinks for both its beauty and long-lasting durability.

The company used advanced engineering to produce a material that is non-porous, repels water and liquids, and withstands everyday wear and tear. Silgranit is stain-resistant, easy to clean, and reduces bacteria growth by an average of 98%. They patented the technology, which they call “Hygienic+Plus surface protection.”

Our question, however, concerns the following point: Can Silgranit sinks be kashered for Pesach? And if not, can they be kashered at all?

What Is It?

First, let’s try to understand what this material is. Silgranit is made from finely ground granite quartz (up to 80 percent) and 20 percent acrylic. It can withstand heat up to 536°F.

Before we get to a discussion of the actual halachah, let us delineate three different halachic areas.

• Firstly, what is the halachah regarding reconstituted stone?

• Secondly, what is the halachah regarding kashering plastic? Is it different if we are discussing a hard acrylic?

• Finally, what is the halachah when discussing a combination of materials? Do we follow the majority of the composite or are we concerned about the minority section of the composite?

Views Regarding Reconstituted Stone

The first to discuss the issue of finely ground stone that was reshaped into a vessel were Rabbi Tzvi Hirsch Shapira (1850–1913), author of the Darchei Teshuvah (121:25), and Rabbi Yehudah Leib Landau (1823–1900), author of the Yad Yehudah (69:81). Both of these poskim forbade the kashering of reshaped stone. These poskim refer to expensive bowls that were made in Russia in this manner, which they consider similar to porcelain. The Yad Yehudah writes so in a definitive manner.

To counter this argument, it is certainly possible, however, that the manufacturing process then was not as sophisticated as it is now. Perhaps the concern was that the heat would cause the stone to crack or crumble and that is why these poskim forbade it. Now the new processing has made the combined mixture of acrylic and granite completely heat-resistant. The Darchei Teshuvah also cites the sefer titled K’mo HaShachar as presenting the distinction between natural stone and crushed stone only as a possibility. If this understanding of the K’mo HaShachar is correct, then perhaps we have a safek in halachah on this very issue. Another possible safek is the first issue, where the manufacturers may have created a truly heat-resistant material.

There may be yet another factor. There are times when the Chasam Sofer (Y.D. #95) has recommended implementing three hagalos, not one, even on a kli cheres, a porcelain dish. True, this is only when the hot item dripping down was considered nifsak ha’kiluach, it was no longer connected to the original vessel, but we do see that the concept is used, and here we are not sure whether it would even be considered cheres. The Pri Megadim, by the same token, in several places (Sifsei Da’as 92:38; M.H. 68:9:4) distinguishes between food and a hard and solid vessel. True, he also only raises this point in regard to a liquid that was disconnected from the original vessel, but, as mentioned earlier, we are not sure that this material should be considered like porcelain.

Finally, there is the view of Dayan Weiss in Minchas Yitzchak (Vol. III #67) who writes that there are poskim who disagree with the Darchei Teshuvah and Yad Yehudah on this matter. The Kochvei Yitzchak (#27) also makes the same point. I am told that this was the view of Rav Elyashiv as well.

Kashering Plastic

Rav Elyashiv, Rav Vosner, and Rav Nissim Karelitz (cited in Mi’Beis Levi Koveitz #9 p.15) were all of the opinion that one may not kasher plastic with hagalah. Rav Moshe Feinstein, zt’l, was also of that opinion (see I.M. O.C. Vol. II #92) but was lenient in regard to using hagalah for a Teflon-coated frying pan that was no longer a ben yomo because it was only a safek d’rabbanan.

On the other hand, Dayan Weiss (Minchas Yitzchak Vol. III #67) was of the opinion that plastic may be kashered with hagalah. This was also the view of the Chelkas Yaakov (Vol. II #167) and the Ohr L’Tzion (Vol. III 10:13).

In Eretz Yisrael, virtually all poskim are only lenient regarding plastic when it is combined with another leniency. In the United States, however, the OU is lenient and allows it at the outset (conversation with the author on March 8, 2021). Rav Yisroel Dovid Harfenes, one of the leading poskim in the United States, is also lenient and allows the kashering of plastic with hagalah.


Rav Elyashiv’s view (cited in Siddur Pesach K’Hilchaso chapter VIII footnote #49) was that there were three situations where one can rely on the lenient opinion that allows for kashering plastic with hagalah.

• When the absorption into the plastic was only through a kli sheini.

• When we are dealing with kashering the handles of a pot

• When the Teflon coating of a new frying pan is smeared with an animal fat.

There is also the view of the Shvus Yitzchak (laws of microwave p. 53) that one can do hagalah three times for something that absorbed something permitted at the time.

Composite Items: Do We Follow The Majority?

The Maharsham in his responsum (Vol. I #53) rules that we go according to the majority of the vessel, whether the outcome is stringent or lenient. However, he writes to be stringent in all situations. The Yad Yehudah (69:33) also urges stringency even when only a minority of the composite material is a material that cannot be kashered. On the other hand, Dayan Weiss (Vol. III #67 and Vol. IV #114:4) indicates that one may go according the majority.


It seems that there is enough room to be lenient and allow for hagalah when dealing with Silgranit, even for Pesach. If one wishes to be stringent, one can perform the hagalah three times. If one wishes to be extremely stringent, one can cover the sink with an insert for Pesach. But, as in all matters of halachah, speak to your own rav or posek. Be sure, however, to show him the aforementioned halachic sources. 

The author can be reached at Read more of Rabbi Hoffman’s articles at


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