Cheres - Self-Cleaning Oven

QUESTION: In an upcoming Halacha Yomis, we will discuss whether there is a possibility of kashering China in a self-cleaning oven. To provide perspective, we will now discuss whether a self-cleaning cycle is considered libun?

ANSWER: There are two basic methods of kashering: hagalah (boiling water) and libun (intense heat). When non-kosher is absorbed with liquid (for example, cooking a non-kosher piece of meat in a pot of boiling water), hagalah is sufficient, but if it absorbed without liquid (such as roasting non-kosher meat on a grill) libun is necessary.

Libun may be performed by using a blowtorch or by heating the non-kosher utensil on a grill until it becomes red hot. What about putting the non-kosher item in a self-cleaning oven and running a cycle? Would that be considered libun? Rav Belsky zt”l (Shulchan HaLevi 24:18) writes that he heard from Rav Yaakov Kamenetzky zt”l and other poskim that a self-cleaning cycle is acceptable as libun. Many self-cleaning oven cycles reach 900ºF, which is adequate for libun. However, Rav Belsky said that even if the oven temperature is only 850 or 800 degrees, this too may be adequate, provided the cycle lasts long enough. Libun burns the residual ta’am (taste) that is in the metal, and a longer cycle will be effective even though it is at a lower temperature. (According to this approach, libun is a function of both time and temperature.) How does one know if the cycle was sufficient? Rabbi Belsky said that if white ash appears on the oven walls and floor, this indicates that the ta’am was burned and the libun was effective.

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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.