Kashering at 212 Degrees

Ask the Rov: A certain kosher item was produced after kashering the machinery at less than 212° F. Is it acceptable?

By Rabbi Chaim Hillel Raskin – Rov of Anash in Petach Tikvah

The halachic rule we follow when kashering is kebol’o kach polto, “the way the prohibited taste was swallowed is the way it is released.” Thus, if the prohibition was absorbed with hot liquid, it could be removed with hot liquid (hagala). But if the absorption was through dry heat, the kashering method required would be purging with fire (libun). Furthermore, the intensity of hagala will vary: if the absorption was in a kli rishon, hagala must be done with a kli rishon, but if it was in a kli sheini, the same would suffice for kashering.¹

Does this rule also determine the temperature needed for hagala, or must one always use boiling water? A utensil can absorb the taste of food that touches it at the temperature of yad soledes — when the hand recoils from the heat — approximately 104° F. If the absorption occurred at 115°, would hagala at 125° be sufficient?

The consensus of major poskim is that only boiling water has the power to extract a forbidden absorption, regardless of the temperature at which the original absorption took place.² This point is evident from Rishonim, and this is how the Rama and Alter Rebbe rule.³ The Pri Megadim, however, writes that although l’chatchila the water should indeed be boiling, mei’ikar hadin non-boiling water could also work.⁴ In cases of serious need, Reb Moshe Feinstein allows for relying on this view, though many prominent kashrus agencies avoid doing so.⁵

At what temperature is water considered “boiling”?

While 212° F is the boiling point for water at sea level, the temperature of the boiling point at higher altitudes is lower. In Denver, Colorado, for instance, water’s boiling point is about 203° F, and hagala could be done in Denver with boiling water at 203° F. While some poskim hold that the water must actually boil, others consider the water’s temperature, regardless of whether it is actually boiling.

Based on the latter view, some kashrus agencies rely on performing hagala at 190° F when needed, since they view this temperature as the “beginning of boiling,” and water in fact boils at this temperature in cities with very high elevations.

The Alter Rebbe doesn’t seem to allow such leniency.⁶ Thus, one should investigate whether a particular hechsher or item relies on this leniency.

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From The Weekly Farbrengen by Merkaz Anash