How to Kasher Your Kitchen for Pesach: A Clear, Step-by-Step Guide

Kashering Utensils

Most utensils absorb a bit of whatever you cook or bake in them, and the next time you use them, they release some of that absorbed taste back into the food. Therefore, utensils that were used even once with chametz must be kashered to use during Pesach.

There are two options for Pesach utensils:

[A] Use a dedicated set of utensils reserved from year to year exclusively for Pesach. This is the recommended option.

[B] Kasher your existing utensils by expelling the absorbed chametz. The kashering method follows the way the utensil absorbed, as follows:

1. Utensils that absorbed chametz through liquids, such as cooking pots, are kashered by immersion in boiling water (hag'alah). That is, you place them into a larger pot of water that is at a rolling boil on the flame, while the water is bubbling (Shulchan Aruch, siman 451 se'if 5; and there, se'if 3; Mishnah Berurah, sif katan 20). The meaning of the word 'hag'alah' is 'expelling' or 'bringing out'—like a person repulsed by something who forces out what has entered within.

The common practice is that after removing the utensil from the boiling water, you immediately place it into a container of cold water (Shulchan Aruch, siman 452 se'if 7).

2. A utensil that absorbed chametz by dry heat without liquids—such as bread and cake baking sheets, metal skewers, or grates placed over coals on which people sometimes grill patties that contain bread crumbs—is kashered by heating it in fire (libun). This means heating it until sparks fly from it (Shulchan Aruch, siman 451 se'if 4). If the utensil is made of a material that would be ruined by such heat, like the common trays in today’s electric ovens, replace them with other trays designated for Pesach, or use disposable aluminum pans. For trays that are usually greased before baking, one who is lenient to kasher them by hag'alah in vigorously boiling water while the pot is on the flame has authorities to rely on (Chazon Ovadia, Pesach, pp. 132–134).

הגעלת כלים (צילום אילוסטרציה: פלאש 90)

3. A Teflon (nonstick) frying pan used without oil cannot be kashered at all, since its use is dry heat and it cannot undergo libun without damage. If it is typically used with oil, kasher it by hag'alah in boiling water on the flame (Yalkut Yosef, Mo'adim, p. 365).

4. A knife is kashered by hag'alah in boiling water while the pot is on the flame (Shulchan Aruch, siman 451 se'if 3; Chazon Ovadia, p. 137).

5. Utensils that absorbed chametz without direct contact with a 'first vessel on the fire' (kli rishon)—for example, spoons and forks—may be kashered in a 'second vessel' (kli sheni), meaning water that was removed from the flame and poured into another container. As they absorbed, so they expel. And even though these are sometimes used to stir a pot of chametz while on the flame, we follow the majority of their use, which is in a kli sheni. All the more so if you kasher them in boiling water while the pot is on the flame, or by pouring (irui) bubbling water over them. (Shulchan Aruch, siman 451 se'ifim 5–6; Chazon Ovadia, Pesach, p. 144).

6. A ladle is kashered by hag'alah in boiling water while the pot is on the flame (Shulchan Aruch, siman 451 se'if 5).

7. Utensils that did not absorb chametz at all—such as a kiddush cup, storage containers for dry chametz where hot chametz is not typically placed, a refrigerator, pantry cabinets, and the like—only require a thorough cleaning with cold water (Shulchan Aruch, siman 451 se'if 1; Chazon Ovadia, p. 147).

8. Earthenware used with hot chametz cannot be kashered for Pesach at all, since it absorbs and does not release (Shulchan Aruch, siman 451 se'if 1).

If earthenware was used with cold liquid chametz—for example, beer—and it sat inside for twenty-four hours or more, it may be kashered by hag'alah in boiling water on the flame. Alternatively, fill it with water for twenty-four hours and change the water every twenty-four hours, for a total of three times; in this manner the water draws out the absorbed chametz (Shulchan Aruch, siman 451 se'if 21; Chazon Ovadia, Pesach, p. 149; see also Or LeTzion, vol. 3, ch. 10, sec. 1). Porcelain and chinaware have the same status as earthenware (Chazon Ovadia, ibid.).

9. Plastic utensils have the status of metal utensils; kasher them according to how they were used (Chazon Ovadia, Pesach, p. 151).

10. The kitchen sink for washing dishes—even if it is made of earthenware—should be cleaned very well, and then have boiling water poured over it (for example, from an electric kettle). It is proper to repeat this process three times (Chazon Ovadia, p. 151).[1]

הספר החדש 'ההגדה של פסח עם פירוש' של הרב זמיר כהן

11. Glass does not absorb at all—even if used with hot chametz. Therefore, thorough washing is sufficient, and it is kosher for Pesach (Shulchan Aruch, siman 451 se'if 26; see Chazon Ovadia, Pesach, p. 152). Jews of Ashkenazi descent customarily act stringently and treat glass like earthenware (Rema, ad loc.).

12. An oven used with chametz during the year is preferably not used on Pesach (see Or LeTzion, vol. 3, ch. 10, sec. 2). However, in principle it may be kashered by cleaning it thoroughly, waiting twenty-four hours from the last use, and then running it on its highest setting for about one hour (Chazon Ovadia, Pesach, p. 132).

Baking trays, however, require libun with direct fire, and since that would ruin them, use new trays or disposable aluminum pans (Chazon Ovadia, ibid.; Or LeTzion, vol. 3, p. 104, s.v. 'Ve-keivan'; see also p. 125, s.v. 'Ve-le'inyan').

13. A microwave used with chametz during the year is preferably not used on Pesach. However, in principle it may be kashered by cleaning it thoroughly, waiting twenty-four hours from its last use, placing a cup with a bit of water mixed with a cleaning agent that will not damage the device, and then running it for several minutes until the walls absorb the steam (Yalkut Yosef, Pesach, 5771 ed., pp. 38, 111–118).

A microwave that also has heating elements for browning is judged like a regular oven (Yalkut Yosef, ibid.).

14. A dishwasher may be kashered by first cleaning it thoroughly, placing detergent inside, and running a full hot-water cycle as usual—but without any dishes. It is best to wait twenty-four hours before this kashering cycle (see Yalkut Yosef, ibid.; and Torat HaMo'adim, p. 245).

15. Burners and grates on which you cook—onto which chametz may sometimes spill—should be cleaned well and have boiling water poured over them. Better yet, perform hag'alah on them (Chazon Ovadia, Pesach, pp. 137–138 and notes 16–17). Some are stringent to wrap the metal arms of the grate with aluminum foil; this is a fine custom (Or LeTzion, vol. 3, ch. 10, sec. 3).

The surface on which the burners and grates rest should be cleaned well, and bubbling boiling water should be poured over it (Sefer Hag'alat Kelim, ch. 13, sec. 132).[2] However, in principle, it is sufficient to clean it thoroughly and cover it with sturdy aluminum foil, even without pouring boiling water over it.[3]

16. The countertop—onto which hot chametz may sometimes be placed or spilled—should have boiling water poured over it (Chazon Ovadia, Pesach, p. 160). Some are stringent to cover the counter with heavy aluminum foil; this too is a fine custom (see Mishnah Berurah, siman 451, sif katan 15).

17. A dining table used with chametz during the year should be cleaned thoroughly and have bubbling boiling water poured over it. If you are concerned the table will be damaged by water, cover it with a tablecloth for the days of Pesach. If the table is used during the year only when a tablecloth is on it, then simply clean the table well and launder the cloth in very hot water (Shulchan Aruch, siman 451 se'if 20; Chazon Ovadia, Pesach, pp. 159–160 and notes there).

18. An electric warming tray (plata) should be cleaned well and have boiling water poured over it while the water is bubbling. Even if bread was warmed on this tray, this pouring is sufficient; there is no need for libun or for covering with foil, since most of the tray’s use is not for heating bread directly (Chazon Ovadia, Pesach, p. 137, note 16 in parentheses; Yalkut Yosef, 5771 ed., p. 40; see also Yalkut Yosef, Mo'adim, 5764 ed., p. 799).

(צילום: יונתן סינדל / פלאש 90)

19. A hot-water urn (micham) that was never used with chametz does not require hag'alah; rinse it with cold water and that suffices (Torat HaMo'adim, p. 245).

However, if it was used even once to heat bread or other products containing chametz, kasher it using one of two options: [A] Clean the urn thoroughly and immerse it in boiling water on the flame; do the same hag'alah for the urn’s lid (Or LeTzion, vol. 3, p. 118; Torat HaMo'adim, ibid.; see also Yalkut Yosef, Mo'adim, p. 765). [B] After cleaning the urn well, fill it with water so that when the water boils it overflows and spills over the exterior as well; ensure that the boiling water flows over the urn’s handles too. Place the lid into boiling water on the flame (Shulchan Aruch, siman 452 se'if 6; and siman 451 se'if 12 regarding utensil handles). For an electric urn that might be damaged by immersion in boiling water on the flame, only the second option is suitable (Shulchan Aruch, siman 451 se'ifim 1 and 7, where we are concerned one might be overly cautious to protect the utensil).

20. The refrigerator and freezer should be cleaned and rinsed thoroughly with cold water so that no crumbs of chametz remain; also clean the door gaskets well using a toothbrush or similar tool, since crumbs are commonly lodged in their grooves (Chazon Ovadia, Pesach, p. 148).

For types of freezers whose ventilation openings have slots that have trapped tiny chametz crumbs that cannot be reached, in principle the nullification of chametz performed before Pesach suffices. It is good to place a bit of cleaning agent in those areas to render any crumbs unfit for consumption.

21. Dentures should be rinsed thoroughly so that no chametz crumbs remain. It is also good to pour boiling water over them from an electric kettle or similar device (Chazon Ovadia, Pesach, p. 145).

22. Do not perform hag'alah for meat and dairy utensils together; kasher them one after the other. If twenty-four hours have elapsed since one of them was last used, you may kasher them together (Shulchan Aruch, siman 452 se'if 2).

If kashering the utensils on the 14th of Nissan, be careful to complete the hag'alah before the fifth halachic hour, so that you will not need to verify whether the utensils are considered 'used today' (ben yomo) or not (Shulchan Aruch, siman 452 se'if 2; see there for additional reasons).

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