5.Warming Trays (Shabbat "Plata"s)
Sauce from ĥametz food occasionally spills from pots onto the warming tray ("plata"), and since the plata is a heat source, the ĥametz is absorbed with the intensity of a kli rishon on the flame. On other occasions, dry ĥametz dishes (such as porridges, kugels, and quiches) fall onto the plata, which constitutes absorption through fire and must be koshered through libun.
A blekh (a metal sheet that is placed atop a gas range on Shabbat) can be koshered through libun if there is no alternative, even though it will warp and become damaged. But when it comes to an electric warming tray, libun is liable to melt the electrical wires and ruin it. Therefore, one must clean it, heat it for an hour, and then cover it with aluminum foil to separate the plata from the Pesaĥ pots. 5 6.Microwave Ovens
The common practice is to kosher a microwave oven in four steps: 1) cleaning it thoroughly of any residual food resulting from spillage or vaporization; 2) waiting twenty-four hours so that the absorbed taste becomes foul; 3) heating a container of water in it for three minutes (since microwave ovens absorb ĥametz via vapor that rises from food as it is heated); 4) placing something as a barrier between the turntable and the food that will be heated in the microwave, because ĥametz may have spilled onto the turntable. 6 7.Dishwashers
The filter, where residual food often gets stuck, must be cleaned thoroughly. Then the dishwasher should be run at its hottest setting, so that any absorbed ĥametz is released, ke-bole’o kakh polto. Regarding the racks, le-khatĥila they should undergo hagala or irui with boiling water or be replaced. If it is difficult to kosher them through hagala or to replace them, one may perform hagala by running them through the dishwasher’s longest and hottest setting.
In any event, one must wait twenty-four hours after the last load of ĥametz utensils before using the machine with Pesaĥ utensils.
Some take a stringent approach to dishwashers and consider them to have the status of a kli rishon on a flame. This means that to kosher a dishwasher one must put a white-hot piece of metal in it in order to boil the water. However, those who follow the lenient approach have authorities on whom to rely. 7 8.The Dining Table
In the past, people would kosher their tables by pouring boiling water over them, and some took the stringent approach of pouring boiling water onto a white-hot stone on the table, so that the koshering would be at the level of kli rishon. However, today’s tables are more delicate and fragile, and would be damaged, warped, or defaced by boiling hot water.
Therefore, the mainstream approach is to clean the table well and affix nylon or paper to it, creating a set barrier between the table and Pesaĥ utensils and foods. In addition, a tablecloth should be spread over the nylon or paper, and it is a good idea to avoid placing boiling hot pots directly on the table.
One may kosher a tablecloth used for ĥametz by laundering it in a washing machine.
Those who wish to knead dough for Pesaĥ must prepare a different surface, because it is difficult to kosher tables for kneading dough.
A table on which no hot ĥametz foods were placed throughout the year must be cleaned well, but there is no need to cover it. 8 9.The Refrigerator and Kitchen Cabinets
Because they are used with cold food, the only concern is that some ĥametz crumbs might remain there. Therefore, cleaning them is what koshers them. In hard to reach places where ĥametz crumbs may have gotten stuck, one must pour soapy water or some other substance that will befoul the crumbs and render them unfit for animal consumption.
When kitchen cupboards were made of natural wood, they often had cracks that were difficult to clean completely from ĥametz that got stuck there. Aĥaronim therefore ruled that the shelves should be covered with paper or cloth (MB 451:115). However, there is no concern that ĥametz remained in smooth shelves like those used today. Therefore, once they have been cleaned properly, they need not be covered with paper or cloth. 10.Pots, Skillets, Silverware, and (Non-Earthenware) Bowls
We detailed the laws relating to hagala of pots in the previous chapter. The principle is that intensity of koshering must match the intensity of absorption (see above 10:8), but the custom, le-khatĥila, is to kosher everything through hagala in a kli rishon (ibid. 9). Before koshering a pot one must clean it (ibid. 10). We have already learned how to perform hagala in practice (ibid. 12), and how to kosher a large pot that cannot be inserted into another pot (ibid. 13).
According to Shulĥan Arukh, skillets are koshered for Pesaĥ through hagala, and during the rest of the year they are koshered through libun. According to Rema, they are koshered through light libun for Pesaĥ as well (ibid. 4). Non-stick or Teflon frying pans cannot be koshered, since people fry in them without using oil that has been brought to a sizzle, which means that such pans require heavy libun. Since this procedure ruins them, they cannot be koshered.
Though eating utensils absorb principally as a kli sheni, the custom is to kosher them through hagala in a kli rishon on the flame. This is because the custom, le-khatĥila, is to kosher all utensils in a kli rishon on a flame. Even if one sometimes uses a fork in a pot on the flame, it may be koshered through hagala because it will be damaged by libun and is batel be-rov (as explained above 10:9 n. 11).11. Blenders and Mixers
Electrical appliances such as blenders and mixers are occasionally used to mince and mix hot and sometimes sharp foods.
Regarding such appliances, one must follow the established principles and always relate to two problems: 1) ĥametz may have gotten stuck in crevices and holes; 2) the taste of ĥametz may have been absorbed into the walls of the appliance.
If such an appliance was used with cold, non-sharp foods only, there is no problem of absorption, but there is still concern that food particles got stuck in its crevices. It must therefore be cleaned thoroughly. If there are grooves in which food particles remain, the appliance may not be koshered; alternatively, it may be soaked in soapy water or in some other agent that renders the residual food unfit for canine consumption.
Mixers have holes designed to provide ventilation for 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 Pesaĥ foods, pieces of ĥametz will fall into the food. In order to kosher a mixer, one must open the motor compartment and clean it thoroughly, or plug up the holes completely. This rule applies to any appliance about which there are similar concerns.
If such an appliance was used with hot foods, and one was not cautious about ĥametz throughout the year, there is concern that it has absorbed the taste of ĥametz. Therefore, one must perform hagala on all parts that came into contact with hot food.
And if such an appliance was used with sharp foods, and one was not cautious about ĥametz throughout the year, even if the foods were always cold, there is concern that contact with the strong sharpness caused the taste of ĥametz to be absorbed by the appliance. One must therefore perform hagala on all parts that came into contact with food (see SA YD 96:1; Kaf Ha-ĥayim ad loc. 1).
If the appliance was used for kneading dough, according to the Sephardic custom hagala is necessary, and according to Ashkenazic custom light libun is needed (based on SA 451:17).
. Sidur Pesaĥ Ke-hilkhato 8:5 states that one should heat up the plata for an hour and then pour boiling water on it, since it has the status of a kli rishon on the flame. It is also good to cover it with aluminum foil. Hagalat Kelim 13:381 states that one may heat it up or cover it with aluminum foil. I believe that the primary solution is to cover the plata with aluminum foil, since it absorbs like a kli rishon on a flame and possibly even like a direct flame, whereas it is doubtful that the standard heat of a plata would reach the boiling point. R. Mordechai Eliyahu also writes that a plata must be covered with aluminum foil.
. I have written in accordance with the currently accepted ruling. R. Mordechai Eliyahu rules that one must also take care to cover any food that he heats up on Pesaĥ. Conversely, R. Nachum Rabinovitch writes that it is sufficient to simply clean the microwave and place a barrier between the turntable and the food. R. Henkin also agreed with R. Rabinovitch.
(The accepted practice for switching between meat and dairy use is as written above. Alternatively, one may hermetically seal all food, or at least one of the types [meat or dairy]. One may also use perforated covers, one designated for meat and one for dairy, every time he heats food in the microwave, which allows steam to escape but prevents it from going into the food. In either of these last two options, one must place a barrier between the food and the turntable. According to R. Rabinovitch, simply cleaning the microwave suffices, even if one did not cover the food.)
. The highest temperature of the water in the dishwasher is c. 80ºC. A dishwasher absorbs at the level of irui from a kli rishon (see above 10:8), since the water is heated by an element (the kli rishon) and then sprayed at the dishes. Thus, ke-bole’o kakh polto applies. Nevertheless, the custom is to kosher all utensils in a kli rishon on a flame; thus, Igrot Moshe OĤ 3:58 states that one should place a scorching hot stone in the dishwasher. When this is difficult, one may perform hagala using the mechanism of absorption, because most poskim maintain that one must perform hagala using boiling water only when koshering a kli rishon used on the flame; when koshering a utensil that absorbed via irui from a kli rishon, the hagala water only needs to reach yad soledet (see above ch. 10, n. 10). This is certainly the case vis-à-vis the dishwasher, which is koshered at least at the same temperature at which it absorbed. Technically, the racks may be koshered in this manner, but since they actually came into contact with food, some authorities ruled that they must be koshered via hagala in boiling water, or at least via pouring boiling water on them (Igrot Moshe). Additionally, some authorities consider the dishwasher to be akin to a kli rishon on the flame; according to these authorities, one must kosher the dishwasher at the intensity of a kli rishon on the flame. According to these authorities, one may only be lenient vis-à-vis the walls of the dishwasher, which do not usually come into contact with food, but not vis-à-vis the racks (R. Pfeiffer’s Kitzur SA, Basar Be-ĥalav vol. 2, explanations 6 and 7). Notwithstanding this stringent view, the mainstream opinion is that the absorption was at the level of irui; therefore, when alternatives are difficult, one may kosher the racks inside the dishwasher. This is the opinion in Hagalat Kelim 13:225-228. Additionally, several authorities maintain that the principle of ke-bole’o kakh polto applies to the temperature of the absorption in a kli rishon, so certainly the dishwasher’s highest setting is sufficient to kosher the trays (see SAH 451:25 and Sidur Pesaĥ Ke-hilkhato 1:4).
Igrot Moshe maintains that if the body of the dishwasher is made of porcelain, it cannot be koshered (this is very uncommon; see also below n. 11 that there are those who are lenient, especially since the food does not touch the walls and it is likely that the dishwashing detergent ruined any taste even before it was absorbed. Thus, there is room to be lenient, as with a sink). See also Sidur Pesaĥ Ke-hilkhato 8:32, which rules stringently and requires one to use a white-hot stone to kosher a dishwasher. Piskei Teshuvot 451:25 states that there is concern about koshering plastic, as some poskim maintain that it is impossible to kosher plastic (ibid. 53). However, the mainstream opinion and the view of most poskim is that plastic can be koshered via hagala, plus this is a situation of uncertainty regarding a rabbinic prohibition, as twenty-four hours have elapsed since the dishwasher’s last use. Hagalat Kelim 13:91 concludes that poskim maintain that plastic utensils can be koshered. R. Dov Lior is lenient regarding all types, as I have written.
. SA 451:20 states that the custom is to pour boiling water on the tables, since ĥametz soup would sometimes spill onto the table. MB 114 adds in the name of Responsa Mahari Weil §193 that since sometimes hot quiches are placed on the table, it absorbs taste on the level of kli rishon, so one would need to kosher it with a white-hot stone. Additionally, it states in par. 17 that one must perform hagala on kneading tablets since dough is routinely left on the tables until it turns into ĥametz, making them comparable to a container for storing sourdough ("beit se’or"). Rema states that the custom is to avoid Pesaĥ use of tables that were used for kneading ĥametz, since they would need to be koshered via light libun. Rema also states in par. 16 that the custom is to kosher a beit se’or via light libun.
It is clear that there is a difference between their tables, made of thick, strong wood that could withstand a koshering process involving boiling water and white-hot stones, and our tables, made of fiber board or plywood covered in Formica, wood veneer, or an alternative. Technically, when necessary one may follow the main use of the table, which is with cold items; therefore, SA states, "the general practice is to pour boiling water on the tables," implying that this is not an absolute requirement. Even according to Rema, who says that the koshering method follows the most severe usage, if the table is separated from the Pesaĥ food by a nylon or paper covering, there is no concern that the food absorbed in the table will pass through the barrier, especially if one is careful not to place boiling hot pots directly on the table, only atop a plate or trivet. Moreover, since our tables are more fragile, people rarely place boiling hot pots directly on the table, so the concern that the table will absorb ĥametz on the level of a kli rishon is more implausible.