Shabbat Parashat Emor| 5770

Ask the Rabbi: Process of Hagala

Question: I have seen books that describe the process of hagala (putting a treif utensil into boiling water to remove the absorbed material) but have not seen a discussion as to how long one has to leave the utensil in. This seems strange especially in regard to treif material that was absorbed over a long period of time.

Answer: The poskim do not give an exact amount of time for hagala; it seems to be a matter of several seconds (see Mishna Berura 452:4). Actually, the Shulchan Aruch (Orach Chayim 452:1) even alludes to the opinion that one should preferably not leave the utensil in for too long (to avoid the situation where the expelled particles return to the utensil). It is hard to argue with the scientific intuition behind your assumption that the more something absorbs, the longer it takes to remove everything that is inside. The Taz (OC 251:23) seems to agree with this idea.

The explanation of the halachic phenomenon appears to be along the following lines, which we will be able to develop only slightly in this forum. Some of the laws of the Torah are purely ritual in nature, and we should not expect them to be based on scientific distinctions or depend too much on specific circumstances. For example, even if there is a correlation between a species of birds being predators and their being not kosher, we would not say that a violent chicken would be treif or a kind vulture would be kosher (Chulin 59a). However, regarding something like kashering a utensil to remove the absorbed tarfut, we might expect that we should be interested in whether we are confident that we were able to remove the requisite amount of absorption.

It can be demonstrated that when the Torah gives instructions as to how to perform kashering (Bamidbar 31:23), its intention was that if the rules are followed, one does not have to be concerned with the possibility that not everything was removed. Halacha says one may assume it, and that suffices. This is the flip-side of a stringent non-scientific assumption regarding absorption. When a utensil was exposed to a food that fit into a category of heat where there is liable to be absorption, we halachically treat the utensil as if it became totally saturated with the substance that it touched. This stringent assumption applies even if the contact was for but a matter of a few seconds. (There is a machloket whether there is some minimum time beneath which there is not absorption- see Pitchei Teshuva, Yoreh Deah 105:8).

It is true that there are sub-rules that are specific to the circumstances. For example, if something absorbed while on the fire, it must be removed while on the fire. If it absorbed with a lesser type of heat, the requirements of kashering are easier. However, the requirement for boiling water does not mean one has to reach the same level of heat as he had during absorption (i.e., even though boiling points vary according to altitudes and depend on what type of liquid is involved, kashering does not differ as a result.)

When we do make distinctions, it is often based on categories of distinctions that the Torah alludes to. For example, we distinguish between the absorption and the ability to kasher utensils made of different materials. Metals are assumed to absorb and release particles normally. On the other hand, pottery is assumed to absorb a lot in a manner that normal hagala will not remove all that it needs to (see Pesachim 30b). The commentaries find the source for the distinction in the Torah itself (see Rashi, ad loc.). Subsequently, authorities discussed other materials such as glass to see which category to attribute it to according to various characteristics (see Shulchan Aruch and Rama, OC 451:26).

Regarding the matter of time, once the requisite conditions for hagala are reached, it does not matter how many times or for how long tarfut or chametz was previously used or for how long we performed hagala regardless of scientific indications.

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