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Weekly Halacha

Selected Halachos relating to Parshas Tzav

By Rabbi Doniel Neustadt

The following is a discussion of Halachic topics related to the Parsha of the week. For final rulings, consult your Rav.

An earthenware vessel in which it was cooked shall be broken; but if it was cooked in a copper vessel, that should be purged and rinsed in water (Lev. 7:21)


As the Biblical verse above states, not all utensils which become non-kosher by absorbing the taste of non-kosher food can be purged, or koshered. For instance, it is impossible to! purge "taste" from earthenware(1). Once an earthenware utensil is rendered non-kosher, it must be shattered and thrown away. On the other hand, metal vessels can be purged of their absorbed taste through a procedure called hag'alah, purging. The halachos of hag'alah are complicated, and what follows is merely an outline of its basic principles. [Unless otherwise noted, the following halachos apply to the Pesach koshering process as well.] Our discussion here refers only to the process of hag'alah, not to be confused with other types of koshering such as libun kal and libun chamur, which have different rules altogether and will be discussed elsewhere.

Which materials can be koshered by hag'alah?

Utensils made from any type of metal(2), stone, wood(3), bone(4) leather(5) or natural rubber(6) may be koshered by hag'alah.

Earthenware(7), china, porcelain(8), glassware(9) and paper(10) utensils cannot be koshered by hag'alah(11).

The poskim(12) differ as to whether hag'alah applies to utensils made out of the following materials: Plastic, melmac, nylon, corningware, corelle, pyrex, duralex, enamel, formica, teflon and silverstone. When possible, these utensils should not be koshered by hag'alah. In cases of absolute necessity or great financial loss, there are poskim who permit these items to be koshered. A rav must be consulted.

Any utensil which may get ruined during the hag'alah process may not be koshered, since we are concerned that its owner will not kosher the utensil properly for fear of damaging it(13). If one koshered such a utensil anyway, it should not be used(14). However, if it was used, the food that was placed or cooked in it does not become forbidden to eat(15).

Which utensils can be koshered by hag'alah?

A utensil becomes non-kosher (or meaty or dairy) if it comes into contact with a non-kosher food item in one of the following manners(16):

DIRECT FIRE: A utensils which is placed directly on the fire with no liquid or minimal oil, butter or shortening added (such as baking pans or parts of a barbecu grill), cannot be koshered by hag'alah(17). A frying pan(18), too, should preferably not be koshered by hag'alah.

INDIRECT FIRE: A utensil which contains liquid and is placed over the fire (such as a pot cooking on a range or a spoon stirring food in a pot on a burner) can be koshered by hag'alah.

HEAT CONTACT: Utensils which come into direct contact with hot, non-kosher food, such as hot non-kosher food placed on a plate, eaten with a fork or poured into a cup, etc.. These utensils may be koshered by hag'alah.

COLD CONTACT: Utensils which come in direct contact with cold non-kosher food must be thoroughly washed with cold water(19). Hag'alah is not required. If the non-kosher food was a liquid and it remained in the utensil for a period of 24 hours or more, hag'alah is required(20).

COLD "SHARP" CONTACT: A cold but "sharp" non-kosher liquid (e.g., onion soup)(21) that was in a utensil longer than 18 minutes(22), or a cold but "sharp" non- kosher solid food that was cut with a knife(23) . The utensil or knife, etc., require hag'alah.

Whenever a utensil needs to be koshered, its cover(24) and handles(25) need to be koshered as well.

How do you prepare a utensil for hag'alah?

Hag'alah purges the taste of non-kosher food which is absorbed into the walls of the utensil, but has no effect on actual food, residue or dirt which may be on the surface! of the utensil. Accordingly, it is imperative that before the hag'alah process begins, the utensil must be scrubbed clean of any actual residue or dirt. Rust spots(26), too, must be removed, since it is possible that particles of food are trapped between the rust and the utensil. One need not be concerned with rust stains, etc., however, since no food particles can be trapped there(27).

Because of this prerequisite, there are several utensils which should not be koshered by hag'alah since they cannot be cleaned properly and thoroughly(28): Utensils which have crevices or cracks where food may be trapped, a pot that has a cover which is attached by hinges(29), a mixer, food processor, blender(30), thermos bottle(31), sieve, strainer(32), grater, grinder, rolling pin, kneading boards(33) and anything else which cannot be scrubbed thoroughly and cleaned in every spot where food may possibly be trapped. If hag'alah is performed on a utensil which was not completely cleaned, it is not valid even b'dieved and the hag'alah process must be repeated.

Handles and covers must be cleaned as well as the utensils themselves. Any handle which is attached with screws should be removed and the area cleaned before hag'alah takes place. If the space between the handles and the utensil cannot be cleaned, the vessel may not undergo hag'alah(34).

Our custom (based on several halachic factors) does not allow a utensil to be koshered by hag'alah if it was used for non-kosher within the previous 24 hours(35). B'dieved, or in a situation where it is difficult to wait 24 hours, a rav may permit hag'alah even within twenty four hours under certain specific conditions(36).

Before hag'alah, the utensil being koshered should be totally dry(37).

In what type of pot is the koshering done:

When koshering for Pesach, it is preferable that the vessel used for the koshering process be either brand new or kosher for Pesach. If this is difficult to arrange, then one may use a vessel which was previously used for chometz, provided that 24 hours have passed since it was last used(38). The custom is to kosher the vessel itself by hag'alah before using it as a receptacle for koshering the other utensils(39). After the hag'alah, the koshering pot should be put away. If it is needed for Pesach, it should be koshered again(40).

When koshering from non-kosher to kosher, the non-kosher utensil should be immersed in a kosher pot. After the koshering process is over, the pot should be koshered again.

When koshering a meaty utensil which became non-kosher through contact with dairy or vice versa, the koshering pot may be either meat or dairy. Neither the utensils being koshered nor the vessel in which the koshering is being done should be used for the previous twenty four hours.

The koshering process:

The following is the correct, l'chatchilah procedure for koshering utensils by hag'alah(41):

A pot with clean(42) water is placed on the fire and the water is boiled until bubbles appear (approx. 212 degrees). Care must be taken that the water continues to bubble throughout the koshering process. In certain cases(43), the hag'alah is invalid if the water was not bubbling at the time of koshering.

The entire non-kosher utensil, including its handles, is placed inside the bubbling water. It should not be withdrawn immediately nor should it be left in too l! ong(44). A few seconds is the right amount of time for the utensil to be immersed in the bubbling water(45).

If a utensil is too large to be inserted all at once into the koshering pot, it may be put in part by part(46). L'chatchilah, care should be taken that no part be put in twice(47).

Immediately upon removing the utensil from the koshering pot, it should be rinsed with cold water. B'dieved, if it is not, the hag'alah is still valid(48).

Although anyone is halachically permitted to kosher utensils, nevertheless, since the halachos are numerous and complex, hag'alah should not performed without the supervision of a talmid chacham who is knowledgeable in this area.

No blessing is recited over hagalas keilim(49).


1. Pesachim 30b.

2. Gold, silver, copper, steel, aluminum, etc.

3. OC 451:8.

4. Rama OC 451:8.

5. Pri Megadim Mishbetzos Zahav end of 451.

6. Igros Moshe OC 2:92.

7. OC 451:1.

8. Mishnah Berurah 451:163.

9. Rama OC 451:26.

10. Pri Megadim OC 451 quoted in Kaf Hachayim 126.

11. In certain cases these types of utensils may be koshered if twelve months have elapsed since they were last used. This kosherization can be done only under the supervision of a rav, since there are several factors involved.

12. There are basically 3 groups of opinions in the poskim regarding koshering these materials: Some allow them to be koshered from non kosher to kosher but not for Pesach; others allow them to be koshered for Pesach as well, while others do! not allow koshering them at all. If at all possible, therefore, koshering these items by hag'alah is not recommended. In extenuating circumstances, however, a rav has leeway to permit koshering these materials. It is important to mention to the rav the manner in which these utensils were rendered non-kosher, since many poskim allow these materials to be koshered if they were not in direct contact with fire.

13. Mishnah Berurah 451:23 and 57.

14. See Aruch Hashulchan 451:20 who holds that once done it may be used, but other poskim imply that even bdieved the hag'alah should not be relied upon.

15. Pri Megadim 451 Aishel Avrohom 19.

16. There are also other issues which need to be explored before declaring a utensil non-kosher, such as the type of food, the amount of food, the degree of heat, etc. All the facts must be presented to a rav for a decision.

17. Mishnah Berurah 451:27.

18. Rama OC 451:11 and Mishnah Berurah 67 and Biur Halachah.

19. YD 121:1.

20. OC 451:21.

21. Mishnah Berurah 447:42; 451:124.

22. Tiferes Yisroel Pesachim 2:4.

23. Mishnah Berurah 447:86.

24. OC 451:14.

25. OC 451:12. Even the poskim who object to koshering plastic by hag'alah will agree that plastic handles may be koshered - Sheorim Hametzuyanim B'halachah 116:10.

26. We are primarily concerned with rust spots inside the utensil. Rust spots on the outside of the utensil which rarely come into contact with food need not be removed - Mishnah Berurah 451:43.

27. Mishnah Berurah 451:22.

28. See OC 451:3 and Mishnah Berurah 22.

29. Mishnah Berurah 451:44.

30. Rama OC 451:18. Se Mishnah Berurah 102 that these utensils pose other problems as well.

31. Mishnah Berurah 451:120 and 156.

32. Rama OC 451:18.

33. Rama 451:16 and Mishnah Berurah 94. See also Biur Halachah.

34. OC 451:3 and Mishnah Berurah 23.

35. Rama OC 452:2; YD 121:2. Some poskim require that the utensil not be used at all in the previous 24 hours, even for kosher items. Accordingly, the utensil should be scrubbed clean before the 24 hours begin - See Mishnah Berurah 452:20 an! d Shaar Hatzion 25.

36. See Igros Moshe YD 2:31.

37. Magen Avraham 452:9.

38. Mishnah Berurah 452:

39. Shaar Hatzion 452:15.

40. Mishnah Berurah 452:10. If the volume of the water in the koshering pot was sixty times greater than the volume of the non-kosher utensil, then the koshering pot need not undergo hag'alah, but this is sometimes difficult to calculate.

41. Unless otherwise noted, all the halachos are based on OC 452 and Mishnah Berurah.

42. The water should not be dirty or filled with detergents and cleaners. Even if, during the koshering process, the water became dirty or filled with brine, it should be changed before proceeding with the hag'alah.

43. It depends whether the utensils became non-kosher by being placed directly on the fire or by coming into contact with heat. A rav must be consulted.

44. Shaar Hatzion 452:28.

45. Shaar Hatzion 452:3.

46. OC 451:11. See Hagolas Keilim pg. 460.

47. Shaar Hatzion 428:28.

48. Mishnah Berurah 452:34.

49. See Darkei Teshuvah YD 121:2; Kaf Hachayim OC 451:200.

Weekly-Halacha, Copyright © 1997 by Rabbi Neustadt, Dr. Jeffrey Gross and Project Genesis, Inc. Rabbi Neustadt is the principal of Yavne Teachers' College in Cleveland, Ohio. He is also the Magid Shiur of a daily Mishna Berurah class at Congregation Shomre Shabbos.

The Weekly-Halacha Series is distributed L'zchus Hayeled Doniel Meir ben Hinda. Weekly sponsorships are available--please send email to the moderator, Dr. Jeffrey Gross

The series is distributed by the Harbotzas Torah Division of Congregation Shomre Shabbos, 1801 South Taylor Road, Cleveland Heights, Ohio 44118--HaRav Yisroel Grumer, Marah D'Asra



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