Pesah Matters – Meqori Perspectives – Part III: Dishes, Ovens, Beliy`ah, and Shopping

[Note: The following is for information purposes only, as is everything on this site. The decision to act or not act upon any of it is the personal decision of the reader and any details regarding the observance of any halakhah – especially those which are intricate and/or are severe – should be discussed with a competent rav.]

My apologies for the long silences between posts lately on Forthodoxy. Between the needs of my family and the demands of university, my schedule has been inundated almost literally from dawn until dusk, leaving me little or no time to post. Hopefully after the semester draws to a close over the next month I will be able to get back to regular bi-weekly posting.

That being said, what I had initially planned to do for this post was a bit more detailed in nature: comparing the halakhoth of bishuley goyim (when obtaining used utensils from a non-Jew), basar be-halav (kashering utensils between uses of meat and dairy), and hagh`alath keliym (kashering utensils from use with hamess for use during Pesah) in the Mishneh Torah to illustrate the similarities and the differences between them. The current practices of kashering come from the Ashkenazi tendency to be mahmir (in nearly everything) and to simply equate all kashering with the laws of hamess, and to equate the laws of tumah and taharah with kashruth. While the interest of these innovations is halakhic “safety,” doing so has spawned numerous urban myths in the Jewish world, as well as heightened anxiety over mistakes and non-issues to almost a breaking point, illustrating again that being “holier than Hazal” only generally causes problems, not improvements.

Although I would like to write a very detailed post on the subject, it will have to wait for now. Instead, I am going to list some practical points with regard to cleaning and the preparation of dishes for Pesah. Hopefully, the following short list will be helpful and will serve to dispel a few myths.

Hahmarah On Pesah

I want to begin by making something absolutely clear: there IS certainly such a concept as being more stringent on Pesah than with regard to kashruth during the rest of the year. We can see this from the fact that while eating a kezayith of a meat and milk mixture would bring a punishment of malqoth by the court (cf. Mishneh Torah, Hilkhoth Ma’akhaloth Assuroth 9:1), the eating of the same amount of hamess (volitionally) brings a punishment of kareth (Hilkhoth Hamess Umassah 1:1). By further contrast, one who cooks food in used dishes of a non-Jew in which was cooked neveloth is only possibly punished with makkath marduth (Hilkhoth Ma’akhaloth Assuroth 17:26) – and possibly not at all. Being that there is such a severe spiritual penalty for eating hamess on Pesah, Hazal took measures to ensure a greater level of kashruth – even beyond that which is practiced during the rest of the year.

But this is the point – it was Hazal who made these determinations. Not only is it unnecessary to go beyond them, but we do not have the authority to do so. The hahmarah (stringency) due during Pesah is already built into the halakhah. The idea that there is the halakhah and then a “higher level” composed of OCD and outlandish concerns is simply false and stems from the false dichotomy between “torahs” presented by the kabbalah and the Zohar. Must it constantly be pointed out how much damage the idea of a “torah” beyond the Torah has done? Shabbetai Zvi (yimah shemo wa-zikhro) anyone?

Dishing It Out

  1. Glass does not absorb – This includes Pyrex, Corningware, Corelle, etc. and they do not absorb either substance or taste. As such, they do not need special kashering for either Pesah or use with meat and dairy. All that is necessary is to scour them with a harsh detergent or bleach solution until they appear “new.” Again, as I have said before, absorption (beliy`ah) is a visibly perceptible process (cf. b.`Avodhah Zarah 33b-34a). There is no such thing as, “You may not be able to see it, smell it, or taste it, but believe me it’s there” when it comes to kashruth. This understanding of the halakhic nature of glass also happens to be the position of the Shulhan `Arukh (OH 451:26) and nearly all the Tosafoth. The Rambam and others only discussed glass serving utensils, not those used for cooking, since cooking or baking with glass did not begin until the 20th century when an oven-safe glass was invented. However, since we can visibly see that no matter what exposure in a kitchen setting it is subjected to, glass cook/bake ware can always be restored to being completely transparent, enabling us to thereby conclude that our new types of modern glass do not absorb either.
  2. Glazed ceramic does not absorb – Like glass, glazed ceramic also does not absorb. Although this is the case for essentially the same reasons as it is for glass, there are some cautions: [i] the glazing should not be cracked. If it is, then it has the status of kley heres (earthenware) and cannot be kashered for Pesah, and [ii] since it cannot be looked through as can glass, great care must be taken to remove all food particles and residue from glazed ceramic dishes before use on Pesah.
  3. Stainless steel does not absorb – In this video, as well as this teshuvah by Rav Ratzon `Arussi, the position of Rav Dov Lior, chief rabbi of Kiryath Arba`, is explained, i.e. that stainless steel is like glass in that it does not absorb. Although most modern poseqim are hesitant to rule this way practically (Rabbi David Bar-Hayyim being a notable exception), there have been many meqori’im who have used stainless steel utensils for both meat and dairy with only a thoroughly cleaning between each use for decades simply due to the scientific nature of stainless steel itself, i.e. that it does not – and indeed cannot – absorb. Using the same rule as noted above, that beliy`ah is a visible phenomenon, scouring stainless steels pots with steel/copper wool and harsh cleaners prior, being careful to remove all traces of food, certainly makes such utensils kasher le-Pesah. One final note about pots and pans: any sort of non-stick coating, etc. makes the utensil(s) not kasherable for Pesah.
  4. Knives may be scoured or boiled – As I have posted previously, knives only need libun gamur when they have been used as a kliy rishon for roasting (as they often were in the ancient world), not when used as we do today. Scouring them and then boiling them in a pot of water (as usually done) is fine, as long as all food can be removed from around the handles. Otherwise such residue needs to be rendered completely inedible – even by a dog (Mishneh Torah, Hilkhoth Hamess Umassah 4:10) – by putting bleach on it (SEE HERE FOR A PRACTICAL OVERVIEW).
  5. Please, for the love of God, do NOT kasher your refigerator – Every year there are people upon whom the Haredi-Hasidic establishment prevails to pour boiling water on every surface on the inside of their refrigerator. This is ridiculous. Neither do your countertops need such scalding treatment. A simple wiping out and thorough cleaning is all that is needed. It is cold and no food is ever cooked in it. Neither is food placed directly onto the shelving without a container (eww).

Out of The Frying Pan and into… The Oven

Cleaning and kashering ovens seems, in the view of many, to be the most daunting task of Pesah kitchen preparation. This, however, does not need to be the case. The Talmudic sources and the Rishoniym discuss ovens on Pesah for many reasons, not the least of which are the baking of massoth and the roasting of the qorban pesah. Under the circumstances of having clay ovens with small interiors, all of these rules would apply. Further, it was the common practice to bake bread, etc. by sticking the dough to the walls of the oven itself – something we also do not do in our modern ovens. For a highlight of several implications of the differences in our modern ovens versus those in the times of Hazal, see `Arukh HaShulhan 92:55 and my post here.

Kashering the oven for Pesah means simply cleaning it with a harsh oven cleaner, wiping and scrubbing the stovetop, and putting it through a self-cleaning cycle. The only concern about the stovetop is that one will set a hot ladle down on it during Pesah while cooking. This can be solved by either covering the middle with a piece of foil (yes, I said it) or putting a kosher plate/trivet there until the end of Pesah. The fear that charred ash (that used to be food) will somehow jump off of the range and up into a pot is ludicrous. Clean it thoroughly and take proper, reasonable precautions. After that, enjoy your Pesah.


Like many things, I wanted to explain this in detail, however I only have time to give you the facts. Many people have become convinced that all products bought for use during Pesah must have a KLP certification. This makes Pesah shopping proprietary and extremely expensive. The fact is that there are only a few products that require such certification and the vast majority of your shopping for the week may be done at your regular grocery store using regular products. Yes, it’s true.

The sons of Rav Yizchak Abadi work tirelessly to confirm the permissibility of a host of products and ingredients for Pesah. They compile their efforts into a list that may be purchased for PDF download HERE, as well as posting thousands of questions on the subject HERE. I would encourage anyone to check out their site and find out just how reasonable your Pesah shopping can be. My kids think that their ability to eat Rice Chex cereals on Pesah is awesome.

Okay, more later. Must run.

Hagh Sameah,


6 thoughts on “Pesah Matters – Meqori Perspectives – Part III: Dishes, Ovens, Beliy`ah, and Shopping

  1. YB,

    What do you mean when you say, ‘any sort of non-stick coating, etc. makes the utensil(s) not kasherable for Pesah.’?


    • לק”י

      Shalom, Shuki.

      As always, thank you for your question.

      I was referring to the plastic coatings that are often put onto the surface of pans which usually end up flaking off after a period of use. Not only is this gross and unhealthy in and of itself, but in my experience food tends to stick in the cracks and under edges. This being the case, I do not think that such coatings are properly kasherable for Pesah. This is also the general opinion of kashruth agencies such as the OU and CRC, although for very different reasons, i.e. non-stick coatings are neither glass nor metal and therefore cannot be kashered. This is not my position. I am coming from more of a practical standpoint that pure, rather than multi-faceted, materials are always better with regard to cleaning and kashering.

      When a non-stick coating is essentially one that is baked-on so that it is virtually as hard as the metal itself and which does not visibly absorb, then I do not think that there would be any issue, le-`aniyuth da`ati, as this seems fairly analogous to glazed ceramic which is treated with respect to kashruth just like glass. The GreenPan line, where glazed ceramic is baked onto metal, would be an example of what I am talking about. Another would be hard-anodized cookware. Both of these options also have the added bonus of not being manufactured from cancer-causing materials, whereas the more common Teflon coating and other cheap “non-stick” coatings contain Perfluorooctanoic acid or Polytetrafluoroethylene which, when they flake off or leach chemically into food, are known to eventually cause cancer and other health risks.

      Hope this helps.

      Kol tuv,



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