A discussion of Halachic topics related to the Parsha of the
week. For final rulings, consult your Rav.
HAGALAH: A KOSHERING PROCESS
As the Biblical verse above states, not all utensils which become non-
kosherby absorbing the taste of non-kosher food can be purged, or
koshered. Forinstance, it is impossible to purge "taste" from earthenware.
Once anearthenware utensil is rendered non-kosher, it must be shattered
and thrown away. On the other hand, metal vessels can be purged of their
absorbed tastethrough a procedure called hagalah, purging. The halachos of
hagalah 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 hagalah, not to be confused with other types of koshering
such as libun kal and libun chamur, which have different rules altogether.
WHICH MATERIALS CAN BE KOSHERED BY HAGALAH?
Utensils made from any type of metal(1), stone(2), wood(3), bone(4),
leather(5), or natural rubber(6) may be koshered by hagalah.
Earthenware(7), china, porcelain(8), glassware(9) and paper(10 )utensils
cannot be koshered by hagalah(11.)
The poskim(12 )differ as to whether hagalah 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 hagalah. 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 hagalah 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 HAGALAH?
A utensil becomes non-kosher (or meat or dairy) if it comes into contact
with a non-kosher food item in one of the following ways(16:)
Direct fire: A utensil 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 barbecue grill), cannot be koshered by hagalah(17.) A frying pan(18,)
too, should preferably not be koshered by hagalah.
Indirect fire: A utensil which contains liquid and is placed directly on
the fire (such as a pot used for cooking on a range or a spoon used for
stirring food in a pot on a burner) can be koshered by hagalah.
Heat contact: Utensils which come into direct contact with hot, non-kosher
food, such as a plate onto which hot non-kosher food is placed, a fork with
which it is eaten, or a cup into which it is poured, etc. These utensils
may be koshered by hagalah. Included in this category are dairy dishes
which were inadvertently washed together with meat dishes or vice versa.
Cold Contact: Utensils which come in direct contact with cold non-kosher
food must be thoroughly washed with cold water(19.) Hagalah 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, however, hagalah is required(20.)
Cold "Sharp" Contact: In the case of a cold but "sharp" non-kosher solid
food that was cut with a knife(21,) the knife requires hagalah(22.)
Whenever a utensil needs to be koshered, its cover(23 )and handles(24 )
need to be koshered as well.
HOW DOES ONE PREPARE A UTENSIL FOR HAGALAH?
Hagalah 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 hagalah process begins, the utensil be scrubbed clean of
any actual residue or dirt. Rust spots(25,) 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, however, since no food
particles can be trapped there(26.)
Because of this prerequisite, there are several utensils which should not
be koshered by hagalah since they cannot be cleaned properly and
thoroughly(27:) Utensils which have crevices or cracks where food may be
trapped, a pot that has a cover which is attached by hinges(28,) a mixer,
food processor, blender(29,) thermos bottle(30,) sieve, strainer(31,)
grater, grinder, rolling pin, kneading boards(32,) and anything else which
cannot be scrubbed thoroughly and cleaned in every spot where food may
possibly be trapped. If hagalah is performed on a utensil which was not
completely cleaned, it is not valid even b'dieved and the hagalah 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
from food that may possibly be trapped before hagalah takes place. If the
space between the handles and the utensil cannot be cleaned, the vessel may
not undergo hagalah(33.)
Our custom (based on several halachic factors) does not allow a utensil to
be koshered by hagalah if it was used for non-kosher food within the
previous 24 hours(34.) B'dieved, or in a situation where it is difficult to
wait 24 hours, a rav may permit hagalah even within 24 hours under certain
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. It is also
permitted to use a vessel which was previously used for chametz, provided
that 24 hours have passed since it was last used(36.) The custom is to
kosher the vessel itself by hagalah before using it as a receptacle for
koshering the other utensils(37.) After the hagalah, the koshering pot
should be put away. If it is needed for Pesach, it should be koshered
When koshering from non-kosher to kosher, the non-kosher utensil should be
koshered in a kosher pot(39.)
When koshering a meat 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 24 hours.
THE KOSHERING PROCESS:
The following is the correct, l'chatchilah procedure for koshering
utensils by hagalah(40:)
A pot with clean(41 )water is placed on the fire and the water heated to a
rolling boil. Care must be taken that the water continues to bubble
throughout the koshering process. In certain cases(42,) the hagalah 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 long(43.) A few seconds is the right amount of time for the
utensil to be immersed in the bubbling water(44.)
If a utensil is too large to be inserted all at once into the koshering
pot, it may be put in part by part(45.) L'chatchilah, care should be taken
that no part be put in twice(46.)
Immediately upon removing the utensil from the koshering pot, it should be
rinsed with cold water. B'dieved, if it is not, the hagalah is still
valid(47.) Although halachically anyone is permitted to kosher utensils,
nevertheless, since the halachos are numerous and complex, hagalah should
not be performed without the supervision of a talmid chacham who is
knowledgeable in this area. No blessing is recited over the koshering
1 Gold, silver, copper, steel, aluminum, etc.
2 O.C. 451:8. However, what is known today as "stoneware" is not made from
stone. It cannot be koshered; ha-Mesivta, 1998, pg. 424.
3 O.C. 451:8.
4 Rama, ibid. See Mishnah Berurah 57 who rules that utensils fashioned out
of a horn may not be koshered, since they may get ruined during the hagalah
5 Pri Megadim M.Z., end of 451.
6 Igros Moshe O.C. 2:92.
7 O.C. 451:1.
8 Mishnah Berurah 451:163.
9 Rama O.C. 451:26, regarding Pesach. Year-round, some poskim hold that
glass never becomes non-kosher; see Igros Moshe O.C. 5:32.
10 Pri Megadim O.C. 451 quoted in Kaf ha-Chayim 126.
11 In certain cases some of these types of utensils may be koshered if 12
months have elapsed since they were last used. This 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 hagalah 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 ha-Shulchan 451:20 who maintains that once done it may be
used, but other poskim imply that even b'dieved the hagalah should not be
15 Pri Megadim 451:19.
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
17 Mishnah Berurah 451:27.
18 Rama O.C. 451:11 and Mishnah Berurah 67 and Beiur Halachah.
19 Y.D. 121:1.
20 O.C. 451:21.
21 Mishnah Berurah 447:86.
22 There are conflicting opinions concerning vinegar, etc., that was in a
utensil longer than 18 minutes; see Tiferes Yisrael, Pesachim 2:4 and
Mishnah Berurah 447:42 and 71; 451:124. A rav should be consulted.
23 O.C. 451:14, since the cover is rendered non-kosher through steam, etc.
24 O.C. 451:12. Even the poskim who object to koshering plastic by hagalah
will agree that plastic handles may be koshered; see Shearim Metzuyanim
25 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; see Mishnah Berurah 451:43.
26 Mishnah Berurah 451:22.
27 See O.C. 451:3 and Mishnah Berurah 22.
28 Mishnah Berurah 451:44.
29 Rama O.C. 451:18. Se Mishnah Berurah 102 that these utensils pose other
problems as well.
30 Mishnah Berurah 451:120 and 156.
31 Rama O.C. 451:18.
32 Rama 451:16 and Mishnah Berurah 94. See also Beiur Halachah.
33 O.C. 451:3 and Mishnah Berurah 23.
34 Rama O.C. 452:2; Y.D. 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 and Sha'ar ha-Tziyun 25.
35 See Igros Moshe Y.D. 2:31. See also Chazon Ish O.C. 122:6 and Y.D. 23:1.
36 Mishnah Berurah 452:13. See Hagalas Keilim, pg. 221.
37 Sha'ar ha-Tziyun 452:15.
38 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 hagalah, but this is difficult to calculate.
39 Mishnah Berurah 452:13 and Sha'ar ha-Tziyun 16-17.
40 Unless otherwise noted, all the halachos are based on O.C. 452 and
41 The water should not be dirty or filled with detergents and cleaners.
Even if, during the koshering process, the water becomes dirty or tainted,
it should be changed before continuing with the hagalah.
42 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
43 Sha'ar ha-Tziyun 452:28.
44 Sha'ar ha-Tziyun 452:3.
45 O.C. 451:11. See Hagalas Keilim, pg. 460.
46 Sha'ar ha-Tziyun 452:28.
47 Mishnah Berurah 452:34.
48 See Darkei Teshuvah Y.D. 121:2; Kaf ha-Chayim O.C. 451:200.