Pesach - Kashering

Cleaning the House for Pesach:

All of us (I hope) will be completing the Sale of Chametz form, and thereby transferring ownership of our chametz to a righteous non-Jewish person. If that’s the case, why is there a need to clean for Pesach, a cleaning culminating in Bedikat Chametz? The answer is that we clean in order to remove from our house (and office and car) any chametz that we might otherwise accidentally discover and be tempted to eat on Pesach. As such, the rule of thumb is that we need to clean out all the places where we may be over Pesach where chametz might exist in edible form and quantity.

In addition, cleaning also insures the credibility of the "bittul" (the verbal nullification) of our chametz that we recite on Erev Pesach. We will be able to say the “bittul” without any reservation, knowing with confidence that there isn’t a bottle of expensive liquor (for example) in some closet that we neither cleaned out nor included in our Sale of Chametz.

Without a doubt, we have a generations-old custom of giving the house a thorough cleaning before Pesach, and this tradition should be honored. But we should understand what the halakhic objective is, and especially when there are so many other Mitzvot calling to us, to set our priorities and use our time appropriately.

Kashering the Kitchen:

Oven: The oven should be cleaned carefully with oven cleaner, and then turned onto "broil" for as long as you typically broil food in your oven. The cavity of the broiler compartment may be kashered in the same manner as the oven, but the broiler pan itself needs to be covered with heavy-duty foil if you want to use it on Pesach. A self-cleaning oven is self-kashering. Allow 2 hours of self-cleaning for this purpose.

Stove top: The surface, grates and jets should all be cleaned well, and you should vacuum out the area beneath the stovetop. There is a custom to let the jets burn for 10 minutes after they have been cleaned. Any part of the range surface onto which you might place a pot or a food item during Pesach should be covered for Pesach.

Glass stovetop: After a careful cleaning of the surface, the coils should be turned on at their maximum height for 10 minutes (not all of them at the same time as this can damage the stove top surface). Over the course of Pesach do not place anything directly onto the parts of the surface in between the coils.  You should place trivets or the like before placing anything down on those surfaces. (In a situation of great need (i.e. you do have anything to place on the surface) you may rely on the position that the glass stove top is not considered halachikly "absorbent", and therefore not "chametzdik" once it has been thoroughly cleaned.)

Counter tops: If they are of kasherable material (stainless steel or stone including Cesarstone) kasher them by pouring boiling water over them, or by "steaming" them with a steamer. In the latter case, be sure that the steamer is producing a coating of boiling water upon the counter. For non-kasherable counter materials, cover the counters throughout Pesach.

Sinks: If they are stainless steel, kasher by (a) not using hot water and washing dishes in the sink for 24 hours and then (b) pouring boiling water over them. If not, you need either to line the sink (with contact paper) or use a sink insert.  

Cabinets, drawers, fridge, and freezer: that will be used to store Pesach food should be carefully cleaned so that no "chametz" remains. No covering is necessary, though some people do have the custom of lining shelves and drawers.

Table tops: should be carefully cleaned and then covered (with a freshly-laundered tablecloth) throughout the holiday.

Microwave: Assuming that you use your microwave as most of us do, primarily for defrosting and warming as opposed to actual cooking, you may kasher it in the following way: Carefully and thoroughly clean all surfaces. The grate-like area on the inside wall should get special attention. After at least 24 hours have elapsed since the microwave's most recent use, bring a cup of water to boil in the microwave, so that the microwave fills with steam. Then move the cup over several inches, and repeat the process. Finally, cover the surface onto which you place the dishes inside the microwave. Wax paper is good as long as you replace the wax paper should it become wet.

Urn: After cleaning both interior and exterior surfaces, and at least 24 hours after its most recent use, fill the urn, plug it in, and allow it to reach its maximum temperature.  After that,  pour boiling water over the spigot, and you are done!. You can kasher your urn even if during the year you have warmed challah on top of the urn,  as the challah (even if not wrapped in foil) does not generally reach the requisite temperature to impact the urn.

Blenders: Carefully clean the appliance to the point at which you are completely confident that is free of any food particles or residue. If you have used the appliance with hot food, then all detachable metal or glass components should be kashered. Metal can be kashered via "hag'alah" (boiling water), and the glass can be kashered according to the information about glass, below.

Dishwasher: Carefully and thoroughly clean all surfaces (including the drain). After at least 24 hours have elapsed since the dishwasher's most recent use, run the dishwasher - with soap - on the longest, most powerful cycle it has.

Which Utensils to Kasher:

As a general rule, metal implements such as silverware, pots, and most other kitchen implements can be fairly easily kashered for Pesach use. Boiling water is the kashering medium we can use. We are generally stringent to only kasher metal baking pans, baking sheets or frying pans through the application of direct heat such as using a blow torch or through placing the item in a self-cleaning oven. There are possible leniencies that would permit hag'alah (in particular in the case of a frying pan which you had typically used with measurable amounts if oil, making it more like pots), so please be in touch with Rav Yosef if you need to discuss this. 

How to Kasher:

The basic process is that of immersion in boiling water.

• To begin, kasher your stove top, or at least the burner you will be using for kashering, FIRST. See “Kashering the Kitchen” above for how that’s done.
• Next, bring a large pot of water to a bubbling boil. It does not matter what kind of pot this is (Pesach or chametz, dairy or meat) as long as it is completely clean, and has not been used in the prior 24 hours.
• The items that you will be immersing in this boiling water should also be completely clean and, ideally, also unused in the prior 24 hours.
• The items should be immersed in the boiling water individually, so that the water touches the entire surface. It is not necessary to immerse the entire object all at once. You can immerse the bottom half, remove the item and then immerse the top half if this is necessary.
• When immersing a pot, you should first remove any removable handles, which should then be immersed separately. If the handles cannot be removed, extreme care should be used in cleaning the point where the pot and the handle meet. Same is true of the lids.
• It is customary to rinse the kashered items in cold water to conclude the process. You can cold rinse all the kashered items together, when you are done with the boiling water portion.
• If you want to kasher a pot that does not fit into your “kashering” pot, here’s the procedure:
  • Fill the pot and bring it to a boil.
  • Simultaneously heat a small object (a stone, a metal implement) on an adjacent burner.
  • When the water in the pot boils, use pliers to gently drop the heated object into the boiling water, causing the water to overflow and thus kasher the outside of the pot as well.
  • This can be a mess, so put towels down in the floor beforehand. Also it may cause the gas flame to extinguish, so be on alert for that.
  • It is not typically possible to kasher the lid of this pot though, as one cannot get the entire lid immersed, even in stages.

Kashering Glass:

• Glass baking or roasting pans cannot be kashered for Pesach according to Ashkenazic practice.
• Glass into which hot liquids were poured (i.e. they were never on a stovetop, in a microwave, or in an oven) can be kashered in one of two ways. You can pour boiling water over and into them (at least 24 hours after their most recent "hot" use). Or you can fill them with cold water (again, at least 24 hours after their most recent "hot" use), empty the water after 24 hours, and then repeat that same process two more times. As a practical tip, it might be easiest to simply place the glass into a tub, fill the tub with cold water covering all the glass inside, drain and refill after 24 hours and after 48 hours.
• Glass that was never used with hot chametz AT ALL simply needs to be carefully washed for Pesach use, though some have the custom is to use the filling/soaking method anyway.
• Click here for a more in-depth explanation on Kashering Glass. 

To top

Kashering Q & A: Stovetop/Oven/Grills/Microwave/Blech

Q: Do I need to refrain from using my stove for 24 hours before kashering it? I have read conflicting things about that online. Published April 2016

A: (RATN) You do not need to wait the 24 hours as you will be kashering the stove grates with libun gamur.

Q: My stove-top grates extend over the whole range, and there are large parts that will not be touched by flames if I kasher on the stove-tops . Placing them in a self-cleaning oven cycle will damage the grates and can also cause a fire (too much metal generating too much heat in the oven, according to what I read). Can I kasher the grates at 500 for an hour (or something like that) rather than self-cleaning? Other recommendations or thoughts? Published April 2016

A: (RYK) Typically, stove-top grates are assumed to instantaneously self-kasher, as drippings from the pots above, burn up immediately. We extend this assumption to the entire area of the grate where a pot would typically sit.  (Note: we have nonetheless developed the proper custom of cleaning and burning the grates for 10 - 15 minutes for Pesach.) If your grates extend beyond the circle where a pot would typically sit, and you do not want to put them into a self-cleaning oven, I'd recommend covering just those parts of the grates with tin foil, in the same way that we cover other parts of the stove top that are beyond the area where the flames burn. 

Q: How do I kasher my non self-cleaning oven (and the broiler below it) Do I need to kasher the broiler in order to use the oven since they are somewhat connected? Published April 2016

A: (RYK) A self-cleaning oven is self-kashering as well, due to the extreme heat that it reaches during the self-cleaning process. Presuming that the broiler section is also reaching this temperature, then it too is automatically kashered. 

Q: Last year was the first time I had a self-cleaning oven (we'd purchased it during the previous year) and using it to kasher the oven for pesach was a bit of a disaster. Can I just do what I used to do before I had a self-cleaning oven and just clean it with oven cleaner and then put it to the highest temp it goes for a couple of hours? Please let me know what you think. Published April 2017

A: (RYK) Yes, you may do what you have done in the past. Clean all surfaces (walls, floor, doors and racks) thoroughly and then do not use the oven for 24 hours. With the racks in the oven, turn to broil (highest heat) for 60 minutes.

Q: Can I use my regular shabbat warming plate on Pesach? Do I need to cover it with foil? Published April 2016

A: (RYK) Clean the surface of the hot plate thoroughly, and cover it tightly with foil for Pesach. 

Q: You gave directions for kashering a microwave, assuming that it is used for defrosting and warming, rather than cooking. What if it actually is used for cooking (without a convection feature)? Published April 2016

A: (RYK) The truth of the matter is, that the thinking about microwaves keeps changing and evolving (as a historical survey of Pesach Kashrut bulletins and magazines would reveal), and it may be that the distinction made above is actually dated and should be changed. There is still not consensus, with some holding that microwaves need no kashering at all (just thorough cleaning), and others (see the Star-K guide for example) agreeing with this position assuming a case in which the walls of the microwave don't become too-hot-to-touch during its typical use. Yet others prescribe the steaming process, again only assuming that the walls don't typically become excessively hot, as above.

Bottom line (for now :)) is that typical Pesach practice still revolves around your particular microwave, and whether its walls tend to become too-hot-to-touch, or typically do not. If the latter, you can feel comfortable cleaning it thoroughly and replacing or covering the glass turntable. Or, if you want to be more machmir, also steaming it per the instructions in the Halacha How To. 

Q: How does one kasher a charcoal grill? Grates are relatively inexpensive. Does buying a new grate help at all?Published April 2016

A: (RATN) You can kasher a charcoal grill for Pesach. First make sure all surfaces are thoroughly cleaned. For the grates, you should do libun gamur, which entails heating the grates to a glow with a blow torch. Since using a blow torch can be dangerous, you are right that buying a new grate may be a better option. Make sure that if you buy a new grate that fits your grill that you tovel it as well. The drum or inside of the grill must be cleaned out completely. Add new charcoal to it and heat it on maximum heat for an hour. If this is too much of a tircha but you really want to grill, you may want to find an inexpensive grill to use for Pesach only.

Q: Can we Kasher our Gas Grill? It goes up to 600 degrees. It has a carbon coated steel grate that the food goes on and the heating plate underneath is porcelain coated steel. Thank you. Published April 2016

 A: (RATN) Unfortunately, because 600 degrees is not equivalent to libun gamur, your grill cannot be kashered for Pesach. You would need to kasher the grates by placing them in a self-cleaning oven or by blow-torching them, and that doesn't sound possible in your case.

To top

Kashering Q & A: Sinks/Dishwashers

Q: Combining 2 questions:
(1) So we can use our dishwashers once we've taken the steps you've outlined using our regular racks (nonmetal racks)? (2) I saw on the site that there are instructions for kashering the dishwasher. If it's not a stainless steel dishwasher, does this still apply? What about the racks? Is this an exceptionally lenient ruling, or have things loosened up over the years? Published April 2016

A: (RYK) The advice re: kashering the dishwasher applies to both plastic and stainless steel dishwashers. The racks, like the walls, need to be cleaned absolutely thoroughly and meticulously, and once 24 hours have passed since the dishwasher’s previous use, the kashering can be done by running the dishwasher with soap for its longest cycle. In my opinion, this is not a lenient ruling at all. It is grounded in the basic principles of kashering.  Being machmir remains stylish of course, but let the machmir be machmir for himself only.

Q: We are supposed to not pour hot water in our sink for 24 hours before kashering (by pouring boiling water). During that waiting period, is it fine to store and wash chametz items in the sink using cold water? (This could work during Shabbat). Published April 2017

A: (RATN) If I understand your question correctly, it is fine if you use the sink in the 24 hour period as long as the water is cold. Be very careful that no one uses the hot water faucet and also make sure that the sink is dry when you actually begin to kasher it. 

Q: Kashering sink question! Our kitchen sink is a black, coated metal (unsure of the exact material used). We're unsure if it's kasher-able for pesach. Our neighbour said it's ok to kasher for general everyday usage but not for pesach however we were told otherwise the year before - confused now. Published April 2016

A: (RYK) Well, a metal sink is certainly kasherable in and of itself, and there's no reason to distinguish between kashrut generally and Pesach kashrut on this point. The only question here might be the coating. If it is a substantial coating made, for example, of a porcelain or glass kind of material, this would be present a kashering challenge. If it is just a thin layer of paint of the suchlike, I wouldn't hesitate to kasher. 

Q: How do I kasher my non-stainless steel sink? Published April 2016

A: (RYK)  porcelain sink can't be kashered. You can either cover it with contact paper for Pesach, or use a snug insert into whose bottom you put a draining hole. (I have many memories of my father a"h, lining the sink with contact paper while saying, "there has to be a better way")

Q: After we had kashered our kitchen for Pesach the kids ate some Cheerios and poured the milk and Cheerios that were left in the bowls into the sink. What are we to do? Do we have to wait 24 hours and then kasher again? This is our dairy sink (the meat one was untouched) Obviously everything was cold. Published March 2018

A: (RATN) It’s fine— because it was cold there is no impact. Just rinse out the sink with soap and water that’s not yad soledet bo (use cold or lukewarm water).

Q: Do we need new sink racks (that line the bottom of the sink) for Pesach? And do we need new dish-drying racks for Pesach? (NOT dish-washer racks. Dish-drying racks, the ones we use after we've manually washed the dishes and are waiting for them to dry.) Thanks! Published April 2019

A: (RYK) Yes, it is preferable to have Pesach versions of all of them.

To top

Kashering Q & A: Kitchen Appliances

Q: I have a kitchen gadget which is truly a one-trick pony. It boils eggs, that is all it does. It consists of a metal plate, a plastic tray for the eggs, and a plastic dome. One pours water in, puts the dome over the eggs, turns it on, and 15 minutes later voila - boiled eggs. My question is whether I can use the same one for Pesach that I use all year, and if so, how would it need to be kashered. Although the only food that comes in contact with it are whole eggs, I do wash the plastic parts with my regular chametz sponges. Thank you. Published March 2025

A: (RYK) By the letter of the law, it can certainly be argued that this gadget need not be kashered at all, as it may very well have never meaningfully contacted chametz food. However, it is very good policy, when it comes to anything that sits on our year-round counters and gets hot, to kasher all of the individual parts. The components you describe can all be immersed in boiling water (hagalah).

Q: Can a hand-held electric mixer (used for baking) be kashered and/or in any other way moved between flavors? In this case we actually have a separate KfP mixer, but it has been used for dairy in the past, and we find ourselves in need of a parve mixer for making a Pesach cake for seder this year. Obviously, we would prefer not to have 2 pesach mixers. Does it matter if the mixer has only been used for cold items? (I believe its only been used for whipped cream)? Published March 2017

A: (RATN) If you are looking to make it pareve then you can just kasher it. But we generally do not move one item back and forth so as to reduce confusion. Just make sure it is thoroughly cleaned (no rust on it) and hasn't been used in 24 hours. Then immerse it entirely in boiling water.

Q: Is there a way to kasher a (glass) smoothie blender? It's got a plastic base and it's only been used for cold drinks (and ice cream). Published April 2021

A: (RYK) Since the blender has only been used for cold food, there is no need to kasher it. It needs to be cleaned thoroughly (take all the pieces apart and wash each one individually), and then you're good.

Q: What about a French press for coffee? It is made of glass, and has obviously had hot liquid in it. There is a metal screen inside and a plastic part where the coffee comes out. If it has never been washed with a chametz sponge is there any way I can make use of this during Pesach? Or do I just need to buy a Pesach-only coffee press? Published April 2016

A: (RATN) If you are able to disassemble, thoroughly clean, and kasher the separate parts [metal via hagalah, glass via milui veirui], you may use it for Pesach. Some coffee is processed on chametz machinery, thus the need to kasher.

Q: I use a coffee grinder and also a glass "pour over" type container during the year. I only use plain whole coffee beans and just rinse it with water and soap, no scrubbing with a brush. Can I use the grinder and glass container for Pesach if I don't use the glass for 24 hours then soak it? Published April 2019

A: (RYK) Under these specific circumstances you may absolutely use it. Just make sure that all the appliances are absolutely clean, and use them for Pesach.

Q: Hello, can we use a cuisinart and/or electric juicer that we use during the year? Thanks! Published April 2019

A: (RYK) In principle, a Cuisinart or a juicer that has only been used with cold food, and which you will only be using with cold food over Pesach as well, can be used after a thorough, careful cleaning. The practicality usually comes down to whether or not it can be thoroughly cleaned, which depends upon the construction of the appliance and if you are thoroughly patient.

Q: I assume my plastic Soda Stream dispenser can be surface cleaned and used on Pesach. Is this correct? I am planning to get new bottles. I usually remove the water deposits on the Soda Stream with a vinegar wash. Is this a problem? Come to think of it, I also clean my urn with a vinegar wash (cold). Problem? Published April 2016

A: (RYK) A cleaned Soda Stream dispenser is a Kosher l'Pesach Soda Stream dispenser, as the dispenser typically does not come into contact with hot chametz food. Even the vinegar was, I assume, not heated when you used it as a cleaning agent. An urn would in principle follow the same rule regarding the use of vinegar-as-cleanser, but it is our practice in any case to kasher urns, with "hag'alah". This is because the urn itself becomes quite hot, and typically sits in our kitchens in close proximity to - and sometimes even in direct contact with - chametz food. The specific instructions as to how to do "hag'alah" on an urn, are found here above.

Q: How does one kasher an Instant Pot/Electric Pressure cooker? Published April 2019

A: (RYK) The CRC rules: An Instant Pot cannot be kashered for year-round or Pesach. The device and its cover have too many nooks and crannies which cannot be cleaned properly, and into which the kashering water might not penetrate.

Q: My hot water pump doesn't work so well so I use a small pitcher (like a creamer) to scoop out the water and pour it in a cup. Since the pitcher has been used during the year (though I can't remember how long ago I used it for its intended purpose) does that make the pump chametz? I would like to use it for Pesach. Published April 2016

A: (RATN) The urn itself does need to be kashered for Pesach in order to be used.

Here are the instructions from Pesach Central at BDJ: "After cleaning both interior and exterior surfaces, and at least 24 hours after its most recent use, fill the urn, plug it in, and allow it to reach its maximum temperature.  After you empty and unplug the urn, bring it over to the sink and simply pour boiling water over the sides, taking care to keep the water away from the electrical component."

The pitcher, which has been inside of the urn at presumably a very high temperature also would need to be kashered for Pesach, assuming it is a kasherable material. Please see here above for more details on how to kasher by material.

On a different note, it might be easier to get a new Pesach urn with a working pump so you don't have to worry about this detail or getting burned! 

To top