Libbun Gamur is the method of koshering that is generally used for utensils which are used directly upon fire—without water. Example: skewers.

In the Talmud, libbun gamur is described as follows:

To what extent is libbun necessary? Rabbi Mani said: “Until its (the vessel’s) outer layer is removed.”

Avodah Zarah, 76a

Alternately, this is described as: Until sparks emanate from the utensil.

Another description: Until the metal becomes red hot.

The above criteria are based upon metals that were used in the days of the Talmud, such as iron. Since the metals of today are made with alloys, even intense heat will usually not produce sparks or cause the metal to become red. Consequently, another benchmark is used:

Until a match which touches the metal would ignite.

This applies to any utensil which is regularly used directly upon fire without liquids. In other words, whether or not the utensil, while being used, ever reached the point of “sparks emanating,” it requires libbun gamur .

Libbun Gamur Options

In practice, how is libbun gamur accomplished?

1.   By using a blowtorch.

      Note: Even one who is skilled in using a blowtorch should not attempt to kosher an oven or any other appliance by using a blowtorch. The process requires one who is knowledgeable in halacha as well as in the use of a blowtorch. In the New York/New jersey area, we recommend Rabbi Avner Katz, 917-751-0343.

2.   By placing lit coals in or around the item to be koshered.

3.   By placing the item in a self-cleaning oven. If the oven itself is to be koshered, the process is the same. It should be noted that a self-cleaning oven reaches a temperature of approximately 900 degrees. This qualifies as libbun gamur.

      (According to G.E.Com, the temperature is 880 degrees, and the time is from 1.5 to 3 hours)

How to do Libbun Gamur: A Step-by-Step Guide

The procedure to be followed in accomplishing libbun gamur, in any of the above-mentioned options, is:

1.   Clean the item thoroughly.

2.   Heat the item, using one of the above-mentioned libbun gamuroptions. (They are: blowtorch,  handled by an individual skilled in koshering with a blowtorch; lit coals; self-cleaning oven.)

      The heating should continue, either, until the item being koshered glows red, or until the outer layer is removed.

      (Or, if using the self-cleaning oven for this process, run the item being koshered through the full self-cleaning cycle.)

3.  Remove the item from the heat.

Points to Keep in Mind about Libbun Gamur

Even if a utensil had been used within 24 hours, it could be koshered by libbun  gamur without waiting. This is not the case with hagalah. Reason: In libbun gamur, whatever was absorbed in the utensil is burned—and therefore does not create a problem. In hagalah, on the other hand, whatever was absorbed in the utensil comes out into the water and could be re-absorbed, making the water unkosher.

On Passover itself (during Hol Hamoed, the intermediate days), libbun gamur or libbun kal—may be performed, while hagalah may not be performed.  Therefore, if one has a utensil that is normally koshered by hagalah, and the individual wishes to kosher that utensil on Passover from hammets to Passover use, it should be koshered by libbun gamur or libbun kal.

Even if the utensil has some rust on it, it may be koshered by libbun gamur.

When a large utensil cannot be placed in the fire completely, it may be partly placed in once, then partly placed in again, until all of it is placed in9.

Following libbun gamur, it is not necessary to place the utensil which was koshered into cold water.

Once a utensil is koshered for Passover use, it emits everything that is absorbed in it. Therefore, one may use a utensil which was previously “meat” for “dairy” and vice-versa—after koshering the utensil for Passover use.

Note: There is no beracha upon libbun gamur.

To see a comprehensive list of various utensils and the methods of koshering them, click here