Using Hagalah is performed by dipping the utensil in a larger pot, as detailed here.

In the case of a large pot or the like, when the item is too large to be placed in another pot, one may follow this procedure:

1.   Make sure to perform the Hagalah before the end of the fourth hour of the day before Passover. (This is the same as the time that is announced to stop eating hammets).

      This allows koshering meat and dairy utensils together and koshering utensils that were used within 24 hours.

      After this time, and throughout Passover itself, hagalah should not be used to kosher vessels and utensils. Only libbun gamur or libbun kal may be used to kosher vessels or utensils.

2.   Make sure that the utensils to be koshered were not used for twenty-four hours.

3.   Make sure that the pot or other vessel in which the utensils will be placed—was also not used in twenty-four hours.

      If it is not possible to wait twenty four hours—place soap or something else inedible in the water as it is being boiled. This renders any taste which is emitted—inedible, and has the same effect as waiting 24 hours.

      Note: If all of the above steps are followed, meat and dairy utensils may be koshered together.

4.   Clean the utensils thoroughly, being especially careful to reach portions of the utensil which are hard to reach.

5.   Fill the pot with water and boil the water.

6.   Since the boiling water must cover the lip of the pot, use a rock or piece of metal. As follows:

7.   Place the rock or piece of metal in fire (holding it with tongs or the like.) Reason: so that placing it in water will not reduce the temperature of the water.

8.   Place the rock or piece of metal in the boiling water, causing the water to spill over the lip of the pot.

9.   Place the pot which was koshered in cold water, or pour cold water upon it.

Question: Must the outside of the pot always be koshered? Must one make sure that the boiling water spills over the rim of the pot and covers the outside?

Answer: If food from the pot normally did not spill over the sides (even if once or twice it did spill over), and if the outside of the pot normally did not come into contact with food—the outside need not be koshered separately. 

If, however, food from the pot normally did spill over the sides; or if the outside of the pot normally came into contact with food—such as in the case of a hot water urn upon which bread was placed for thawing out; or if a vessel was used to remove hot liquids from another vessel—the item should be koshered from the outside. Though there is another opinion, namely, that koshering the inside of the pot koshers the entire pot, one should follow the strict opinion, since it does not require much more effort.

Points to Keep in Mind about Hagalah

Once a utensil is koshered for Passover use, it emits everything which 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.

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.

There is no beracha upon hagalah.

Any portion of the utensil which is being koshered which cannot be reached by the water—may be koshered by libbun kal. Moreover, one can replace hagalah entirely with libbun kal.

In certain instances, hagalah by pouring is enough to kosher a utensil. To learn about hagalah by pouring, click here

For a comprehensive A-Z listing of how to kosher various utensils and appliances for Passover, click here