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The following responsum is reprinted from Tomeikh KaHalakhah volume 2. Tomeikh KaHalakhah is UTJ’s series of volumes of responsa (teshuvot) promulgated by the Union For Traditional Judaism’s Panel of Halakhic Inquiry.
The text below is the result of OCR. Although it has already been reviewed, if you identify any errors, kindly email office@utj.org. A scan of the original teshuvah is available here.
The essential principle that underlies the kashering process of purging a vessel of any forbidden substance it might have absorbed which renders it unfit for use is kevole’o kakh pole to, “as the vessel absorbs, so does it rid itself of what it absorbed” (Pesahim 30a).
The Talmud (Pesahim 30b) notes, however, that ” … The Torah testified regarding earthenware vessels that it never loses its defect.” For this reason the standard halakhic rule is that earthenware, enamel, porcelain, and glazed chinaware cannot be kashered (OrahHayyim451: 1; Rabbi Eliahu Schlesinger, Sefer Ma’ aglei Eliahu, par. 1, pp. 23-24; Rabbi Aaron Felder, Oholei Yeshurun, vol. 1, p. 74; Rabbi Isaac Klein, Guide to Jewish Religious Practice, p. 113). The impossibility of kashering earthenware vessels applies to substances absorbed through the medium of heat. Substances absorbed through long-term soaking, though technically con- sidered “cooked”, may be removed through soaking or purging (Shulhan Arukh of Rabbi Shneur Zalman of Liady, Orah Hayyim 451:61).
Even the more stringent form of kashering called libun, that is, heating by flame until the object to be purged glows from the heat, may not be efficacious for these materials since the owner may not apply sufficient heat over sufficient time because of the fear that the items to be kashered may break on account of the heat (ibid.). The sole exception, according to some authorities, would be when items made from such materials are returned to the potter’s furnace (ibid. and also Rabbi Samuel Burschtein, Ma’ adanei Shemuel 116:4). In this case there is no concern that the vessel in question would be prematurely removed from the heat. Today, few if any Jews have access to such a procedure, making it no more than a remote halakhic solution.
The less stringent form of kashering called hag’ alah, that is immersion in boiling water, is even less efficacious considering the porosity of earthenware and china. Thus, Rabbi Joseph Karo permits the kashering of earthenware utensils by three successive immersions only in cases where scriptural law does not apply, for example, vessels in which Gentiles had cooked food which are prohibited only by rabbinic legislation (Shulhan Arukh, Yoreh De’ ah 113: 16 and see Burschtein, op. cit. 116:3).
Notwithstanding the Talmud’s absolute stand against kashering of earthen- ware vessels (“~ loses its defect”), in the case of earthenware left unused for a long period of time, one major early modem rabbi questioned whether the Talmud’s ruling should be taken so literally. In 1709 the Hakham Tzvi, Rabbi Tzvi Ashkenazi, one of the leading authorities in Germany, responded to a case where one of his students wanted to forbid the food cooked on Passover in an unpurged metal pot that had once been used for year round cooking but had not been used for two years (Responsa Hakham Tzvi, no. 75). His student reasoned that the leaven absorbed in the walls of the pot would linger and the impaired flavour imparted into the food would make it unfit for Passover use. If, however, this logic were accepted, argued the Hakham Tzvi, even after a thousand years the pot would still be unusable for Passover, and this did not make sense.
Rather, he ruled, after twelve months have elapsed, that which was absorbed into the pot is now to be considered “like dust” and is therefore of no consequence. Moreover, he extended his ruling even to earthenware and to year round-not just Passover-purging. He was even inclined to rule that the twelve month limit applies not only retroactively to Passover foods accidentally prepared in a pot which had remained unused but even to cases where one intentionally leaves a pot unused so that it could be “kashered” in this manner. However, he could not bring himself to go that far.
Subsequent authorities are divided as to whether to accept Hakham Tzvi’s ruling. For a comprehensive list, see Rabbi Samuel Burschtein, Sefer Ma’ adanei Shmuel, section 116:1, subparagraph 1. The upshot of both the lenient and strict views is that the view of the Hakham Tzvi, if it is accepted at all, is accepted after the fact (bedi’ avad) , that is, if the pot was already used for cooking, then the food is not forbidden. The Hakham Tzvi himself, as was noted, was unwilling to go one step further and allow kashering earthenware vessels through “aging” in the first instance (lekhathila), even though he did make the theoretical case for such permission. Facing particularly urgent situations, some com temporary rabbis, however, have relied on the view of the Hakham Tzvi to allow kashering and subsequent use of porcelain or earthenware dishes. Rabbi Ovadia Yosef (Hazon Ovadia, p. 48, footnote 28), cites a decision of the Israeli chief rabbinate allowing hotel keepers to use porcelain vessels for Passover after they have been purged three times in boiling water, but he cites several rabbis who object to this permis- sion. When he was chief rabbi in Cairo in the late 1940’s, Rabbi Ovadia Yosef himself had to find a way to make kosher the facilities in Cairo’s Jewish hospital, knowing full well that community officials would be unwilling to make a large outlay of funds to replace all the dishes. Faced with the alternative of the hospital’s remaining non-kosher, Rabbi Yosef ruled that the staff could kasher the porcelain dishes (afterthey had remained unused for 24 hours) by immersing them three times in boiling water (Resp. Yabia Omer, Yoreh De’ ah, Part I no. 6). Rabbi Yosef’s ruling refers to an emergency situation, and it is doubtful that it could be applied universally (see, however, Sha arei Teshuvah on Orah Hayyim 451, subparagraph 1).
On the basis of the above sources, we find that enamel, porcelain and glazed china can be kashered only if a great loss (hefsed merubeh) would be incurred by the owner and only after passing of a full twelve months since the dishes were last used (Rabbi Hayyim Hezekiah Medini, Sedei Hemed, Hametz uMatza 7:2; Rabbi Aaron Felder, Oholei Yeshurun, p. 74 and notes). If such leniency would aid in encouraging particular families to make their homes kosher, this would be an additional reason in favor of following the Hakham Tzvi ‘s precedent (Rabbi Moshe Feinstein, Resp. Iggerot Moshe, YorehDe’ ah part 2 no. 46).
Authorities are divided on the procedures to be followed at the end of this period. Rabbi Aaron Felder (op. cit.) insists that after the passing of twelve months, the utensils in question must still undergo three successive immersions in boiling water, changing the water each time. Most of the authorities cited above, however, make no mention of any special procedure to be followed at the end of this period. Nonetheless, it would still be appropriate to rinse the dishes off after the twelve month period just as all utensils are rinsed after kashering (Shulhan Arukh, Orah Hayyim 452:7).
See also TomeikhkaHalakhah, vol. I, p. 51.
Rabbi Wayne Allen and Rabbi Gershon Bacon for the Panel of Halakhic Inquiry.
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Born and raised in New York City and currently a resident of Toronto, Rabbi Wayne Allen has blended a career of service to the Jewish community as an ordained rabbi with his academic pursuits. Rabbi Allen is recognized as an expert both in Jewish law and in 18th century British moral philosophy. The books he has written and those he has edited are distinguished by the inclusion of philosophical analysis and historical context, adding an extra dimension to the more traditional forms of responding to questions on Jewish practice. He is a panelist for Jewish Values On-line, an Internet site devoted to providing authoritative answers to questions on Jewish life.
Rabbi Allen has traveled extensively and has led groups to Europe and Israel, lecturing beforehand on the history of the communities to be visited. He has served as a faculty member at the American Jewish University where he taught Jewish law, at California State University Long Beach where he taught the History of Modern Jewish Thought and Zionism, and at the University of Waterloo where he taught Theology After the Holocaust. He has also been invited as a guest lecturer at York University in Toronto and at the Pardes Institute in Jerusalem.
Rabbi Allen has served as a scholar-in-residence at synagogues in St. Louis and Ottawa and currently teaches at the Community Hebrew Academy of Toronto where he serves as chairman of the Rabbinics Department.
Samples of Rabbi Allen’s teaching are accessible on his website, www.rabbiwayneallen.ca.
Rabbi Allen's published books, available from the UTJ Bookstore are: