11 – Kashering the Kitchen for Pesaḥ

01. Countertops and Sinks

The kitchen sink and countertops are generally used with cold foods, but sometimes hot liquids spill onto them from a kli rishon, and in such cases their usage is at the level of irui mi-kli rishon. And sometimes burning hot quiches and pastries or pots from which sauce is overflowing are placed on them. In these cases, their usage is at the level of “kli rishon removed from the flame,” which is kashered by pouring boiling water over a white-hot stone.

If it were not difficult, it would be proper, le-khatḥila, to kasher them by pouring boiling water over a white-hot stone, but since this is difficult to accomplish, one may kasher them le-khatḥila by pouring boiling water over them, in accordance with most of their more intense usage. Before pouring the hot water over them, one must clean them well with soap and water, paying attention that no food residue remains in cracks. One must then dry the sink and countertop before pouring, so that the boiling water touches them directly and is not cooled by any cold water on their surface. For this reason, one first pours the boiling water on the bottom of the sink, then on its walls, and then on the countertop, starting with the areas closest to the sink and moving further away.

In home kitchens, the custom is to kasher the sink and countertops using water that was heated up in an electric kettle (“kumkum”). Since the kettle is not large enough to heat up enough water all at once, the kashering is done in stages; in each stage, water boiled in the kettle is poured over one area. If the poured water trickles over to an area that has not yet been kashered, one must squeegee it away before pouring more boiling water from the kettle over it.

Instead of pouring hot water, one may also cover the countertops with oilcloth or foil and either place a plastic insert in the sink or line it with thick foil. Those who are stringent clean and pour hot water over the countertops and sink and also cover the countertop with oilcloth or thick foil and either place a plastic insert in the sink or line it with thick foil.^[1]

[1]. Le-khatḥila, the method of kashering required is determined by the most intense usage, and in times of necessity, by the majority of usage (above, 10:7). In the case of sinks and countertops, kashering based on majority use is by cleaning and rinsing with cold water, but since it is possible to perform a higher level of kashering, this is the custom. Therefore, countertops have the same status that tables had in the past (below, n. 8), i.e., even though most usage was with cold, since sometimes people would place burning hot quiches on them, the custom became to kasher them by pouring boiling water on them. Some were even more stringent and poured the boiling water over a white-hot stone. If dough is kneaded on the countertop, then its most intense usage has the status of a surface on which dough was kneaded: some say it is kashered by means of hagala, and some say it is kashered by means of light libun (below, n. 10). Kashering countertops based on the more intense usage requires pouring boiling water over a white-hot stone, as by means of the stone the poured water becomes hotter and kashers at the level of hagala in a kli rishon (SA 451:16). In practice, kashering with a white-hot stone or white-hot iron can cause damage, so these surfaces should be kashered by pouring boiling water, which kashers at the level corresponding to most of the more intense usage. Those who are stringent also cover the countertop with a fixed cover like oilcloth or with aluminum foil. Those who wish to suffice with a fixed countertop cover may do so, but those who are stringent are concerned that the cover will move. Those who are stringent are also concerned that aggregate stone countertops have the status of earthenware, but this concern is baseless, as it is known that countertops do not absorb flavor like earthenware or even wood. Therefore, pouring boiling water over them is effective even le-khatḥila.

Sinks have the same status as countertops. However, if the sinks are made of porcelain, some are concerned that it has the same status as earthenware, in which case hagala is not effective. Therefore, they require the placement of a plastic insert or lining the sink with thick foil to serve as a barrier between the sink and the kelim placed therein (Ḥut Shani, Pesaḥ 10:17; Sidur Pesaḥ Ke-hilkhato 8:1, which adds that a stainless-steel sink is kashered by pouring boiling water over a white-hot stone). However, porcelain sinks are made very well, and their coating is as impenetrable as glass. Therefore, they can be kashered (see below, n. 11) le-khatḥila by means of pouring boiling water, and, when necessary, by rinsing. (Ḥazon Ovadia, Pesaḥ, p. 151 rules that one may kasher by pouring boiling water; Or Le-Tziyon 3:10:11 states that one may kasher by rinsing or cleaning with cold water, but the custom is to pour boiling water.)

One may kasher sinks and countertops with a steam cleaner, as long as it is high-quality, and it is as effective as pouring boiling water on them. However, burning alcohol on sinks and countertops is not as effective as pouring boiling water, as is evident from the fact that it does not heat up the countertops like pouring boiling water does.

02. Gas, Electric, Ceramic, and Induction Stovetops

Throughout the year, people usually use the same stovetop grates for both meat and milk, because even if some meat or dairy liquid spills onto them, the flame incinerates and befouls it (Peninei Halakha: Kashrut 25:9).

Technically, for Pesaḥ as well, regular cleaning suffices. However, due to the seriousness of the ḥametz prohibition, people customarily perform light libun on such grates to kasher them for Pesaḥ (Rema 451:4; MB ad loc. 34). Alternatively, one may wrap thick aluminum foil around the bars on which the pots sit, creating a barrier between the Pesaḥ pots and the grates that came into contact with ḥametz. In addition, it is customary to turn on all the flames and let them burn for about 15 minutes.

For the areas of the grates that do not come into contact with the pots, the enamel cook top beneath the grates, and the burner caps, it is sufficient to clean them well.^[2]

Electric ranges: Clean thoroughly and run on the highest setting for about 15 minutes.

Ceramic burners: The surface on which the pots are placed is like smooth, impervious glass. This surface is heated up electrically, and it, in turn, heats up the pots on it. Based on the principle of ke-bole’o kakh polto, they are kashered by cleaning and then heating them up on the highest setting for about 15 minutes.

Induction cooktops: The surface on which the pots are placed is like smooth, impervious glass. However, unlike ceramic burners, in which the heat source is within the ceramic surface, in induction cooktops the heat source is in the pot, which heats up by means of a magnetic field. From the pot, the heat spreads to the food cooking within it and to the surface on which it is standing. Ḥametz is liable to be absorbed into the cooktop via food that overflowed from the pot, some of which can get stuck to the base of the pot and continue to heat up along with it. Such cooktops are therefore kashered by cleaning them and pouring boiling water over them. Kashering them from the food that overflowed and got stuck to the bottom of the pot is based on the principle of ke-bole’o kakh polto: wet the bottom of the pot when they are empty, and heat them up on the cooktop for about 15 minutes. (Below, in section 14, the obligation to kasher glassware is discussed.)

[2]. Due to the stringency of the ḥametz prohibition, light libun is required (MB 451:34; Kaf Ha-ḥayim 451:74). Some maintain that hagala is sufficient (Ḥazon Ovadia, Pesaḥ, p. 137). Covering the grates with aluminum foil is as effective as light libun since it completely separates the grate from the pots, so even if some liquid spills, it would not connect the grate and the pot. If food was cooked on Pesaḥ on grates that were not cleaned, the foods are kosher.

03. Baking Ovens and Trays

The oven itself and the racks on which trays are placed are kashered by cleaning them and running the oven on its hottest setting for half an hour.

Baking trays are not kashered because they absorbed through fire, and kashering them requires libun at a temperature of 400^oC, which will likely cause them serious damage (above, 10:5 and 9). One should therefore buy special baking trays for Pesaḥ, while the ḥametz trays should be cleaned and put away like all other ḥametz utensils. Instead of special Pesaḥ trays, one may use disposable trays.^[3]

[3]. With regard to the oven walls, the entire concern is for steam that may have been absorbed into them and will be released by the walls, thus rendering Pesaḥ food forbidden. Therefore, it is certain that the oven can be kashered by heating it to a high temperature. Even if a ḥametz dish once spilled and was absorbed into the oven itself, since there is no direct contact between the oven itself and the Pesaḥ foods, and the only concern is for steam that it might release, heating the oven to its highest temperature is sufficient. (This is also the view of R. Shlomo Zalman Auerbach in Halikhot Shlomo 3:2; however, Ḥazon Ovadia, p. 132, and Ḥut Shani 10:2 state that one must also wait 24 hours, as is customary before hagala. Nevertheless, in practice, this is not necessary since it is being kashered by means of libun, as explained in Peninei Halakha: Kashrut 25:11). Even though heating the oven itself to its highest temperature kashers it, it is customary to clean it as well. Ovens that self-clean at more than 400^oC need not be cleaned before kashering even according to custom.

Baking trays in which ḥametz is baked cannot be kashered because custom follows the stringent view (above, 10:5) that requires a temperature or 350-400^oC to kasher them by means of libun, which will damage them. However, one who wants to rely on the lenient view, that even libun only requires heating up to the temperature at which the baking took place, may kasher the baking trays in the oven, as explained above (10:5).

04. A Warming Tray (“Plata”) and Barbecue Grills

A warming tray (“plata”) is forbidden on Pesaḥ because of baked goods that are placed on it and because of cooked foods that sometimes spill on it. Since it absorbed through fire, it must be kashered through libun. However, libun will damage it, and as we learned, when necessary, kelim that absorbed through fire can be kashered by heating them up to the temperature at which the absorption took place (above, 10:5 and 10:3). Therefore, one may kasher a plata by cleaning and heating it up for an hour. Those who are stringent also cover it with aluminum foil to create a barrier between the plata from the Pesaḥ pots.

A grill: The body of the grill and the racks are kashered the same way they are used, which is at the intensity of heavy libun. If it is a gas grill, it is kashered at the highest temperature setting; if it is a charcoal grill, it is kashered by putting in the largest amount of charcoal that one regularly uses.

05. Microwave Ovens and Dishwashers

There are three steps to kashering a microwave oven: 1) cleaning it thoroughly of any residual food resulting from spillage or steaming; 2) heating a bowl of water for about ten minutes at the highest setting – to kasher it from ḥametz steam and vapor using the principle of ke-bole’o kakh polto; 3) since there is concern ḥametz may have spilled onto the plate that sits on the microwave’s turntable, one must clean the plate and perform hagala on it with boiling water, or, alternatively, place something as a barrier between it and the food that will be heated in the microwave on Pesaḥ.^[4]

Dishwashers: The filter, where residual food often gets stuck, must be cleaned thoroughly. Then the dishwasher should be run, with its racks, at its hottest setting, so that any absorbed ḥametz is released, ke-bole’o kakh polto.^[5]

[4]. The year-round status of a microwave is explained in Peninei Halakha: Kashrut 25:11, n. 12. Regarding the plate, some say that according to Sephardic custom, the glass plate does not absorb, so cleaning it is sufficient (Yalkut Yosef), whereas according to Ashkenazic custom and Ben Ish Ḥai, the plate is considered meat, dairy, or ḥametz, depending in which food touched it. Based on what we explain below (section 14) and in Peninei Halakha: Kashrut (32:5), one should be stringent, as stated above, since this level of intensity is similar to that of a kli rishon.

[5]. Some are stringent and consider dishwashers to have the status of a kli rishon on a flame. This means that to kasher a dishwasher one must put a white-hot piece of metal in it in order to bring the water to a boil. However, those who follow the lenient approach have authorities on whom to rely. Others are stringent about this because they have a custom, le-khatḥila, to kasher everything in a kli rishon on the fire. So state Igrot Moshe, OḤ 3:58, and Sidur Pesaḥ Ke-hilkhato 8:32. However, in practice, a dishwasher should not be considered a kli rishon, because only where the water is heated up is considered a kli rishon. However, from there the water is injected into the hollow center of the dishwasher, and when the water arrives there it has the status of something poured from a kli rishon – and ke-bole’o kakh polto. Regarding what Rema writes, that there is a custom to kasher everything in a kli rishon, this is only le-khatḥila, and even then, it is only due to the concern that the kli may have been used in a more intense fashion. In the case of a dishwasher, there is no such concern; this is the accepted ruling (Hagalat Kelim 13:225-227; Or Le-Tziyon 3:10:11 states that technically it is permissible to kasher just by cleaning). See Peninei Halakha: Kashrut 25:8, n. 10.

06. The Dining Table

Tables of the past were made of thick, solid wood. People would put burning hot pastries and boiling pots on them, so ḥametz dishes would occasionally spill on them. Therefore, the custom became to kasher tables by pouring boiling water over them (SA 451:20), and some were more stringent, pouring boiling water onto a white-hot stone on the table (Mahari Weil). However, today’s tables are more delicate and fragile, and would be damaged, warped, or defaced by boiling water. Since the tables are so delicate, people do not place boiling pots or burning hot pastries directly on them.

Therefore, one must clean the table well, as this kashers the table in according to its majority usage. But since sometimes hot ḥametz liquids can splash onto the table, and sometimes people place hot pastries on it, it is proper to take care not to eat at the table without a tablecloth serving as a barrier between the table and the food.

Some are scrupulous to affix nylon or contact paper, out of concern that the tablecloth placed on the table will move around, but affixing them creates a permanent barrier, over which one places the tablecloth. If it is a table on which one occasionally kneads dough, a permanent barrier must be placed or affixed to it.^[6]

For a table on which no one places hot ḥametz foods and no one kneads dough, it is sufficient to clean it well, and there is no need to cover it.

One may kasher a tablecloth on which ḥametz was eaten by laundering it in a washing machine. If a tablecloth cannot be washed, one should clean it and keep it in a locked cabinet with the ḥametz dishes.

[6]. SA 451:20 states that the custom is to pour boiling water on the tables, since ḥametz soup would sometimes spill onto the table (even though most of its use is with cold, and technically cleaning it is sufficient). According to Responsa Mahari Weil §193, since sometimes hot quiches are placed on the table, it absorbs taste at the level of kli rishon, so one would need to kasher it with a white-hot stone. Several Aḥaronim wrote that le-khatḥila one should act accordingly (Eliyah Rabba, Pri Megadim, MB 451:114). However, people do not place boiling pots or burning hot pastries directly on contemporary tables, which are comparatively fragile and delicate. At most, we place pots on a trivet, and occasionally ḥametz food spills from them onto the table, or we place hot – but not burning hot – pastries on the table, so pouring boiling water kashers it effectively even from its more intense usage. Yet even pouring boiling water can ruin the table. Therefore, it is proper to place a barrier on it. If it is a table on which one occasionally kneads dough, a permanent barrier must be affixed to it. This all follows the accepted view (above, 10:7) that le-khatḥila we are concerned about most intense usage. But be-di’avad, when necessary, even if it was used for dough, as long as its surface is smooth and there is no concern that ḥametz got stuck in its crevices, one may suffice with cleaning and rinsing, in accordance with most of its usage. Or Le-Tziyon 3:10:10 accepts this le-khatḥila.

07. The Refrigerator and Kitchen Cabinets

Because the refrigerator and kitchen cabinets are used with cold food, the only concern is that some ḥametz crumbs might remain there. Therefore, cleaning them is what kashers them. Hard to reach places where ḥametz crumbs may remain must be cleaned with soapy water to befoul crumbs that may be there and render them unfit for a dog’s consumption.

When kitchen cupboards are made of natural wood, it is hard to clean their cracks and crevices from ḥametz. If one does not wish to wet them with soapy water, he should clean them as well as he can and cover them with paper or cloth (MB 451:115).

08. Cutlery, Pots, and Skillets

We detailed the laws relating to hagala of kelim in chapter 10. The operative principle is that the intensity of use dictates the intensity of absorption, but the custom, le-khatḥila, is to kasher everything by means of hagala in a kli rishon (10:6). Therefore, the custom is to kasher cutlery in a kli rishon on the flame even though they absorb principally from a kli sheni. Even if one sometimes uses a fork with something on the fire, since it would be damaged by libun, it may be kashered through hagala, in accordance with the majority of its usage (10:6-7).

Before kashering, one must clean the kelim (10:9). We have already learned how to do hagala in practice (10:11) and how to kasher a large pot that cannot fit into another kli (10:12).

Regarding a skillet, le-khatḥila it is kashered by means of light libun, but one who wishes to kasher it by means of hagala may do so (10:4). A skillet that is normally used without oil – to fry malawach, for example – must be kashered by means of heavy libun (4, n. 3). Non-stick or Teflon skillets cannot be kashered since they are intended for frying without using oil. This means that they must be kashered by means of heavy libun, but since this procedure would ruin them, they cannot be kashered.^[7]

[7]. In times of need, such skillets can be kashered by means of light libun, in accordance with those who maintain that ke-bole’o kakh polto applies to the temperature of libun as well, combined with the opinion that the absorption of ḥametz throughout the year is considered the absorption of permissible matter (heteira bala; above, 10:5). Under extenuating circumstances, one may kasher them by means of hagala, in accordance with those who maintain that ḥametz is considered heteira bala (above, 10:3).

09. Kelim and Machines Used for Kneading and Mixing

Kelim used for kneading – the surface on which the kneading takes place, the rolling pins, and the parts of mixing and kneading machines that come into direct contact with dough – must be kashered by means of hagala. Even though the dough is cold, since the acidity of the ḥametz in the dough can intensify the absorption of the taste of ḥametz, they must be kashered via hagala (Ri, Raavyah, Rosh, SA 451:17). Some are more stringent, maintaining that hagala is ineffective for such kelim (Rashi, Rabbeinu Tam), because it is hard to clean off the dough that was absorbed in crevices. However, they can be kashered by means of light libun. If they have no crevices, they can by kashered via hagala (Rema 451:16-17; MB 94).^[8]

Mixers have holes whose purpose is to ventilate the motor, so that it does not overheat. Flour and pieces of dough splatter into these holes, and there is concern that, when used with Pesaḥ foods, pieces of ḥametz will fall into the food. Since it is hard to clean, it is better not to kasher it, but when there is great need for a mixer, one must open the motor compartment and clean it thoroughly.

[8]. The Talmud (Pesaḥim 30b) explains that kelim used with ḥametz cold are kashered by means of hadaḥa (rinsing), but kelim that were used with dough, whose acidity is harsh, cannot be used on Pesaḥ. According to most Rishonim, the meaning is that hadaḥa is not sufficient to kasher kelim used with ḥametz, but hagala is (Arukh, Ri, Raavyah, Rabbeinu Yeruḥam, and Tur. Others said that the Talmud refers to earthenware kelim, for which hagala, too, is ineffective; so say Rif, Ritz Gi’at, and Rambam as interpreted by Magid Mishneh. It stands to reason that these Rishonim would agree that kelim used for kneading ḥametz that are made of other materials can be kashered by means of hagala). Some are stringent, maintaining that even hagala is ineffective for these kelim (Rashi, Rabbeinu Tam, Rabbeinu Shimshon of Sens). Therefore, Rema wrote (451:16-17) that they are kashered by means of light libun. Many explained that hagala is ineffective for bowls used for dough because they have crevices that cannot be cleaned properly (Smak, Baḥ, Gra). Some are more stringent, maintaining that hagala is ineffective because the acidity of the ḥametz is absorbed intensely in the kli, so this would apply even to kneading kelim that have no crevices (MA). In practice, according to most Aḥaronim, if the kelim have no crevices, even those who adopt the stricter interpretation of the Talmud would agree that the kelim can be kashered by means of hagala (MB 451:94).

10. Various Other Kelim

Silver goblets: The custom, le-khatḥila, is to perform hagala on silver goblets used for kiddush wine, because ḥametz crumbs sometimes fall into the goblet and soak in the wine for 24 hours, and sometimes they soak in whiskey for 18 minutes (above, 10:13). Since this is a remote concern, if necessary, one may suffice with just rinsing them, in accordance with their majority usage.

The custom is to perform hagala on electric urns (such as those used on Shabbat) and kettles, because ḥametz crumbs may have fallen into them. Hagala is done by filling the device with as much water as possible, bringing the water to a boil in the same manner that the water is boiled all year round, and then letting some water out through the tap or spout through which the water is dispensed. Before hagala, it is best to clean out the stone deposits that accumulated inside. When the lid of an urn is made of metal and one regularly places challah loaves on it to warm them before a Shabbat meal, hagala in boiling water must be performed on the lid.^[9]

Thermos: After cleaning it properly, hagala in boiling water is performed. It is also possible to kasher it by pouring boiling water into it and on its opening.

Pop-up toasters and sandwich makers require heavy libun, and since this is liable to damage then, they should not be kashered. (Although we explained above, 10:5, that in times of need we are lenient and allow libun at the same temperature as the usage, since these appliances are difficult to clean, there is no room for leniency.)

A blender that is used to grate, chop, and dice foods – if it was used with cold foods, it is kashered by means of rinsing. If there are grooves in which food particles may remain, the appliance should be cleaned with soap until it is clear that any residual food is unfit for a dog’s consumption. If the appliance was used with hot foods, and one was not careful about using it with ḥametz all year round, all of the parts that touched hot foods should be kashered by means of hagala.^[10]

False teeth: These should be cleaned thoroughly before the onset of the ḥametz prohibition. They need not undergo hagala, because people do not normally put boiling foods or liquids in their mouths; just as they are used for both meat and dairy when cleaned in between, so can they be used on Pesaḥ.

[9]. This matter is unclear. Since there is no liquid present and the challah reached the temperature of yad soledet, perhaps it should be considered to have absorbed the taste of challah as though by means of direct fire, meaning that the lid would need libun, and regular libun will damage the lid. The custom is to be lenient because we factor in the view that ḥametz throughout the year has the status of “heteira” and thus hagala is effective where normally libun would be (as explained above, 10:3).

[10]. If a blender was used with cold, sharp foods (that are so sharp that they cannot be eaten by themselves), and one was not careful about using it with ḥametz all year round, it must be kashered le-khatḥila by means of hagala, as we are concerned that the combination of the strong abrasive action with the sharpness of the food caused the flavor of ḥametz to be absorbed into the appliance (SA, YD 96:1; Kaf Ha-ḥayim 1). If the kelim are made of metal or glass, or were not used with hot foods, then even if they were used with sharp foods, they can be kashered by rinsing them. (We explained in Peninei Halakha: Kashrut 32:12, n. 15, that the special status of sharp foods is the subject of disagreement among Rishonim and Aḥaronim; since our glass and metal kelim do not absorb or release flavor, we follow the lenient view and consider sharp foods as we treat all other foods.)

A coffee machine: One cleans it and heats up water to the highest temperature in the normal manner.

11. Earthenware and Porcelain Kelim

If an earthenware kli absorbs ḥametz hot, even if it was in a kli sheni, hagala is not effective. It is also impossible to kasher it by means of libun (above, 10:9). If used cold, however, one may kasher it by means of hadaḥa, that is, by cleaning and rinsing it. If a ḥametz beverage sat in it for 24 hours, one may kasher it by means of hagala or by soaking it three times, each time for 24 hours (SA 451:21; above, 10:13). Clay and ceramic kelim are considered earthenware.

The poskim are divided about the status of porcelain (china). Porcelain is made as an earthenware kli, but it is coated with glass by brushing it with or immersing it in the substance from which glass is made. In practice: le-khatḥila, porcelain kelim should not be kashered, but in times of need, as long as there are no cracks, they can be kashered by means of hagala.^[11]

[11]. The poskim are divided about the status of porcelain. Radbaz (Responsa Radbaz 3:401) wrote that it is proper to be stringent and consider it earthenware, as it is hard to know whether the coating is impervious. He even conducted an experiment: he cooked in a porcelain kli and found that its weight increased a bit, implying that it absorbed matter. Many showed concern for his view, including: Pri Ḥadash 451:26; Maḥzik Berakha 451:10; MB 451:163; Ben Ish Ḥai, Tzav 14; R. Ḥayim Palachi in Mo’ed Le-kol Ḥai 4:3; and Kol Mevasser 1:80. Against them, many practiced leniency and considered it to be like glass. Several poskim ruled accordingly, including Shiyarei Knesset Ha-gedola OḤ 451; Hagahot Beit Yosef 30 (though he was personally stringent, he did not agree to this stringency for others); and She’elat Ya’avetz 1:67. Rav Goren ruled accordingly for the IDF with regard to porcelain plates that have no cracks and that are generally used with a kli sheni (Meshiv Milḥama 2:150).

It seems that the primary reasoning of those who adopt the stringent view is concern that the glass coating is imperfect. It emerges from Pri Ḥadash and Ḥida (Maḥazik Berakha) that if the porcelain is real, there are grounds for leniency, but it is often counterfeited. Indeed, in the past, many would coat the earthenware with a glasslike substance with a paintbrush, and sometimes the coating was imperfect and had cracks. However, when the earthenware is immersed in liquid glass, the coating is uniform, smooth, and strong. Therefore, although le-khatḥila one should show concern for the stringent view, when necessary, one may be lenient, since nowadays the manufacture of porcelain is high quality, i.e., the glass coating is strong and the kli does not absorb. However, when the kli has cracks, its status reverts to being like earthenware.

Today there are high-quality plates made (by Arcopal and others) from sand. Their texture is hard like glass, and, as can be seen when they break, the interior material is hard and impervious, like glass. Although their surfaces are made rough for aesthetic reasons, they have the status of glassware and are kashered by means of hagala, as will be explained in the next section.

12. Glassware

A dispute arose in the time of the Rishonim regarding glass kelim. Some say that since glass is smooth and hard, and even if it held hot foods, the taste of those foods is not absorbed into it and does not adhere to it. Therefore, even if glass kelim were used with prohibited foods or ḥametz throughout the year, it is sufficient to clean them thoroughly to enable their use for kosher food or on Pesaḥ (Raavyah, Rosh, Rashba, Ran, SA 451:26).

Others disagree, saying that since glassware is made of sand, like earthenware, even if glass kelim do not actually absorb, they have the status of earthenware, which cannot be kashered. Therefore, if one used them with hot ḥametz foods, there is no way to kasher them for Pesaḥ (Rabbeinu Yeḥiel, Smag, Rabbeinu Peretz, Terumat Ha-deshen, and Rema).

Still other Rishonim adopt a middle position. In their view, glass kelim have the same status as metal kelim. If they were used with boiling hot ḥametz food, they must be kashered by means of hagala in boiling hot water (Rambam, Or Zaru’a, and Shibolei Ha-leket).

Many Sephardim follow the lenient opinion and kasher glassware by rinsing it only, and many Ashkenazim have the custom not to kasher glassware. In practice, however, it seems that the middle position, according to which glassware has the same status as metal kelim and can be kashered by means of hagala, is primary. Those whose family custom is to be lenient may maintain their custom, and those whose family custom is to be stringent should maintain their custom.^[12]

[12]. In Peninei Halakha: Kashrut 32:5, n. 3, this issue is addressed extensively. The following is a summary: Most Sephardic rabbis rule leniently that glassware may be kashered by rinsing, in accordance with SA 451:26, Pri Ḥadash, Shetilei Zeitim, and Sha’ar Ha-mifkad. Many contemporary poskim ruled likewise, as cited by Alei Hadas, Netivei Am, Shemesh U-magen, and R. Ovadia Yosef. Some are stringent and require hagala, including: Rav Pe’alim, R. Ḥayim David Ha-Levi, R. Mordechai Eliyahu, R. David Shloush, and R. Kapaḥ. It seems that in the past, glass was not strong and durable enough to be used in a kli rishon on a flame, so the Rishonim and Shulḥan Arukh, who permit glassware with rinsing and without hagala, were referring to kelim whose most intense use was at the level of irui or kli sheni. There are also differences of opinion among Ashkenazic poskim. Rema 451:26 rules stringently that glass kelim cannot be kashered for Pesaḥ by means of hagala, but be-di’avad, if they were cleaned, hot food placed in these kelim is not forbidden (Darkhei Moshe 451:19; Taz 451:30). According to MA 451:49, one may be lenient, be-di’avad, only after kashering by means of hagala. Ḥok Yaakov 451:68, SAH 451:73, Mekor Ḥayim 451:46, and Maharsham concur. Some rule that hagala should be performed three times on glassware, because according to Itur, hagala three times is effective after 24 hours even for earthenware kelim (Tzitz Eliezer 9:26, quoting R. Tzvi Pesaḥ Frank). Many have written that we rule stringently and do not kasher glassware only when it comes to ḥametz, but one may kasher kelim from other prohibitions by means of hagala. This is the view of Maharam Brisk, Seridei Esh, Beit Avi, and Minḥat Yitzḥak. According to She’elat Ya’avetz 1:67, technically one may kasher glass kelim by rinsing them, but due to the severity of the ḥametz prohibition, the custom developed to avoid using them. Beit Leḥem Yehuda, Ḥamudei Daniel, and Yad Yehuda state similarly. Since there are differences of opinion among both Sephardic and Ashkenazic poskim, I wrote in favor of the middle position for all communities.

13. Kelim of Enamel, Plastic, and Other Materials

Enamel kelim are made of metal and coated with a thin layer of enamel for aesthetic reasons. The inside of the pot is usually painted white, while the outside is decorated with different colors. Enamel is made of sand like glassware, but it is manufactured differently. In practice, one may perform hagala on enamel kelim like all other metal kelim.^[13]

The same applies to all types of metals, leather, wood, and bone. Only earthenware cannot be kashered, because, due to the unique composition of earthenware, it absorbs a lot and does not release all that it absorbs.

Plastic kelim that have absorbed the taste of boiling hot food are kashered via hagala with boiling water, like all other kelim. However, sometimes plastic kelim get scratched, making it hard to clean them well. Therefore, the accepted recommendation is to replace plastic baby bottles and pacifiers before Pesaḥ, as it is hard to clean them to the point that their original shine is restored. Nevertheless, in times of need, they can be kashered by means of a good cleaning and hagala or pouring boiling water from a kli rishon.^[14]

[13]. At first, poskim were uncertain about enamel because its craftsmen kept enamel’s composition secret. Then, when it became known that enamel is sand-based, uncertainly arose again as to whether such kelim have the status of earthenware. Responsa Ḥatam Sofer (YD 113) states that enamel is kashered via light libun. R. Shlomo Kluger rules stringently that one may not kasher enamel even via libun, since it might get damaged in the process (Tuv Ta’am Va-da’at 1:183). AHS YD 121:27 states that it can be kashered by performing hagala three times, relying on the view of Itur that triple hagala is effective even for earthenware kelim once 24 hours have passed since their use with prohibited food. The accepted ruling is that they can be kashered by means of hagala, since they are primarily metal and the enamel coating is like glass. This is the view of Aderet, and so state R. Mordechai Eliyahu’s Hilkhot Ḥagim 5:39 and Ḥazon Ovadia, Pesaḥ, p. 157.

[14]. Igrot Moshe (OḤ 1:92) states that one should not perform hagala on kelim made of plastic or other synthetic materials not mentioned by the Rishonim, since such materials might be like earthenware, which does not release what it has absorbed. This is also the view of R. Yaakov Shaul Elyashar and Lehorot Natan 6:69. Nonetheless, most poskim agree that plastic kelim can be kashered by means of hagala. These include: Responsa Ḥelkat Yaakov 2:163; Seridei Esh 2:160; R. Levi Yitzḥak Halperin; R. Mordechai Eliyahu, Hilkhot Ḥagim 5:86; Ḥazon Ovadia, Pesaḥ, p. 151; and Or Le-Tziyon 3:10:13.

15. Enamel Utensils

Enamel utensils are made of metal and coated with a thin layer of enamel for aesthetic reasons. The inside of the pot is usually colored white, while the outside is decorated with different colors. Enamel is made of sand like glassware, but it is processed differently. Great uncertainty arose regarding such utensils. At first, poskim were uncertain because the craftsmen kept enamel’s composition secret. Then, when it became known that enamel is made of sand, uncertainly arose again as to whether such utensils have the status of earthenware.

In practice, the poskim rule that one may perform hagala on enamel utensils like all other metal utensils, and some recommend performing hagala three times. Yet regarding Pesaĥ, some instruct not to perform hagala on enamel utensils in light of the severity of the ĥametz prohibition.^[13]

[13]. Responsa Ĥatam Sofer YD 113 states that enamel is koshered via light libun. R. Shlomo Kluger rules stringently that one may not kosher enamel even via libun, since it might get damaged in the process (Tuv Ta’am Va-da’at, first edition §183). Ktav Sofer YD 78 permits koshering enamel via triple hagala. SHT 451:191 quotes Ĥatam Sofer and then states that many great authorities were more stringent in this matter when it came to Pesaĥ. This is also the view of Maharsham 1:53. Aderet rules that one may kosher such utensils via hagala, but out of respect for Ĥatam Sofer states that one should use triple hagala (which according to Itur works even for earthenware vessels once twenty-four hours have elapsed since they were last used). This is also the opinion of AHS YD 121:27. R. Mordechai Eliyahu states that one may kosher these utensils for Pesaĥ via hagala, and preferably triple hagala.

16. Plastic Utensils

Plastic utensils that have absorbed the taste of boiling hot food are koshered via hagala with boiling water, like all other utensils. This is true of all types of metal, such as silver, copper, iron, aluminum, etc., as well as utensils of leather, wood, and bone. It is earthenware alone that the poskim say cannot be koshered, because, due to its unique composition, it is very absorbent, but does not release all that it absorbs. And some poskim say that glassware has the same status as earthenware.

However, Igrot Moshe (OĤ 1:92) states that one should not perform hagala on utensils made of plastic or other synthetic materials not mentioned by the Rishonim, since such materials might be like earthenware, which does not release what it has absorbed. Nonetheless, the overwhelming majority of Aĥaronim agree that hagala is effective on plastic utensils, and this is the halakha. Utensils made of hard plastic are koshered through hagala in a kli rishon on the flame, whereas plastic utensils that are liable to be damaged in a kli rishon on the burner can be koshered at the same level they absorbed the ĥametz.^[14]

[14]. Those who ruled leniently are: Responsa Ĥelkat Yaakov 2:163, Seridei Esh 2:160, Tzitz Eliezer 4:6, and many others. This is also what Hagalat Kelim states in 13:91. Sidur Pesaĥ Ke-hilkhato 9:25 assigns greater weight to the stringent opinions, and states that triple hagala seemingly works according to everyone (based on the opinion of Itur that triple hagala is effective even on earthenware vessels once twenty-four hours have elapsed since their last use, although it seems that one needs to change the water between each stage of hagala; see Sidur Pesaĥ Ke-hilkhato 9:25 n. 10). It seems proper to wait twenty-four hours, ensuring that any absorbed taste is foul, in which case hagala is only rabbinically required, and one may be lenient in a case of uncertainty about a rabbinic law.

Peninei Halakha