Editors’ note: The following article by Rabbi Dr. Ephraim Rudolph is the second part of a series on Kashering one’s mouth for Pesach. The first article of the series can be found on https://www.koltorah.org.
Rav Ovadya Yosef, in his work Yechaveh Da’at, spells out the three most fundamental reasons why one can be lenient on the subject of Beli’ot of Chameitz, and not require a separate pair of dentures for Pesach. The first two reasons focus on why there are no Beli'ot or Ta’am transfers when it comes to the mouth in general, and the third reason is why there are no Beli'ot specifically in dentures. The first reason that Rav Ovadya discusses is the concept of Keli Rishon versus Keli Sheini. A Keli Rishon is the pot in which the food was originally cooked on the fire; a Keli Sheini is the vessel into which the food was first transferred. For example, if a piece of meat was cooked in a pot and then placed on a plate, the pot is a Keli Rishon, and the plate is a Keli Sheini. The Shulchan Aruch (Yoreh Dei’ah 105:2) quotes two opinions concerning the status of a Keli Sheini with regard to Ta’am transfer. One opinion is that there is no transfer of Ta’am in a Keli Sheini, no matter what the temperature of the food is. The second opinion states that there is a transfer up to a Kelipah, which is a peel’s worth. This means that there is some absorption of Ta’am, but it doesn’t penetrate through the entire Keli (only the ‘peel’, or outermost layer). The Shulchan Aruch believes that LeChatchilah one should be careful, but BeDi’eved Beli’ot in a Keli Sheini do not transfer Ta’am, and rinsing the food is good enough. This means that if there was hot chicken soup in a bowl (which is a Keli Sheini) and some pizza fell in the bowl after one ate the soup, the pizza is Kosher BeDi’eved, but one must wash the bowl.
Many other Poskim (such as the Badei HaShulchan) say that one should be strict and throw everything out unless it is a serious loss or pressing situation. The reason (Shabbat 40b Tosafot s.v. Shema Minah) given is that since the walls of the new plate or bowl are cold, the food will be cooled and therefore not hot enough to transfer Ta’am. However, since we eat foods on a plate (not a pot straight out of the oven) we do not need to worry about this stringency.
In the context of Pesach, Rav Ovadya Yosef notes that there is a debate as to the opinion of the Shulchan Aruch. The Shulchan Aruch holds (451:5) that a Keli Sheini that had Chameitz needs to be Kashered for Pesach. Some are of the opinion (Bach 447 and Shach Yoreh Dei’ah 105:5) that the Shulchan Aruch is being strict by Pesach that a Keli Sheini does transfer Ta’am. However, Rav Ovadya quotes others, such as the Magen Avraham (451:13), who argue that the Shulchan Aruch is only saying that LeChatchilah there is a concern of transfer of Ta’am with Keli Sheini, but BeDi’eved even by Pesach a Keli Sheini does not transfer Ta’am. As the Shulchan Aruch seems to say in 447:3, there is no concern by a Keli Sheini. Rav Ovadya goes further and quotes the Aruch HaShulchan who writes that even according to the Rama (451:3), who says we should be strict by a Keli Sheini for Pesach, this is only a Chumrah (stringency), but not the Ikar Halachah (true Halachah). Even according to those who are strict by a Keli Sheini for Pesach, Rav Ovadya suggests that teeth may be different. He states that the mouth should be considered a third separate vessel, a Keli Shlishi. The Chofeitz Chaim writes in Sha’ar HaTziyun (451:10) that we are lenient for Chameitz by a Keli Shlishi. (Aruch HaShulchan 447:23 agrees.) Therefore, if one views the mouth as a Keli Shlishi, then Pesach would not pose a problem of transfer of Ta’am.
However, there are a number of issues with this first approach presented by Rav Ovadya Yosef. The first is a practical one: sometimes one who is cooking the food tastes the food that is on the stove, so that it is from a Keli Rishon (rendering the mouth a Keli Sheini). The second problem is that many authorities are in disagreement that a Keli Sheini cannot transfer Ta’am BeKulo (in the entire piece). These authorities hold that as long as something is boiling it can transfer Ta’am, even if it is not Pesach. Furthermore, if the food is in a Keli Shlishi, it has the strength to be Mavli’a (absorb) and Maflit (release) Ta’am.
Furthermore, some authorities say that this rule of the Shulchan Aruch and Rama is only for liquids, but would not apply to a Devar Gush (solid). Solid foods are even stricter: a boiling hot solid food retains the status of a Keli Rishon and can even be Mevasheil (cook). It can also transfer Ta’am in a Keli Shlishi, as long as it is Yad Soledet Bo (literally, hot enough that
one would retract their hand from it).
The second approach which Rav Ovadya Yosef discusses is that the temperature of the food entering the mouth is not hot enough to cause any transfers of Ta’am. The Gemara (Shabbat 40b) says that the heat for Bishul (and we assume for Ta’am well) is Yad Soledet Bo. The Gemara defined this as the temperature which will burn up a baby’s stomach. This temperature is hard to measure for obvious reasons; therefore, Rav Yoseif quotes the Ben Ish Chai who writes that the definition of Yad Soledet Bo is food that cannot be placed in your mouth because it is too hot. Rav Ovadya Yosef states that the Maharsham (1:196) also wrties that anything that could burn one's mouth is a Yad Soledet Bo. Therefore, there can be no Beli'ot created in your mouth because nothing placed in your mouth is hot enough to transfer any Beli'ot into the fillings. Does this leniency apply for Pesach as well? The Maharsham actually quotes a Machaloket about whether food in the mouth can be Yad Soledet Bo. In the context of milk and meat he says one can be lenient, but in the context of Pesach perhaps one should be strict.
There is an issue with this Kula (leniency) as well, because most modern day Poskim have determined that we eat and drink foods that are Yad Soledet Bo. The exact temperature of Yad Soledet Bo is a big discussion amongst the Poskim. Rav Dovid Ribiat, author of the famed work “39 Melachos”, quotes Rav Moshe Feinstein who says it can be anywhere from as low as 110 degrees to as high as 160 degrees. Rav Aharon Kotler says it is 120 degrees. Rav Shlomo Zalmen Auerbach, citing a sugya in Chullin 8a, says it is 113 degrees Fahrenheit. These temperatures are actually lower than some temperatures of food that are put in our mouths. Rav Ribiat writes that coffee is usually about 125 degrees, hot tea is about 165 degrees, and hot chicken soup is 180 degrees. Rav Shlomo Zalman Auerbach, in his work Michat Shlomo, says that according to those opinions, Yad Soledet Bo is “Kreisho Shel Tinok Nichvit Bo,” “A baby’s stomach is burned by it,” and some hot liquids are hotter than that. He also quotes the Pitchei Teshuvah (Yoreh Dei’ah 105) who states that anything hotter than saliva is considered Yad.
Therefore, it does seem that food of a temperature at or above Yad Soledet Bo is regularly placed in the mouth according to many opinions. In conclusion, it would appear we should be strict by milk and meat as well as for Pesach.
The third Kula mentioned is that the dentures themselves are made out of materials that cannot absorb taste. Rag Ovadya quotes the She’alot Shalom (Mahadurah Tinyana 195) and the Darchei Teshuva (99:11) who asked a doctor who claimed that dentures do not absorb taste, as it would cause the denture to smell and be a source for germs.
This Kula may also be difficult on a scientific level. Many dentures are made with metal components which should absorb Ta’am just like other metals. The non-metal dentures are really a form of plastic; plastic is subject to a debate among the Poskim as to whether it has the status of a Keli Cheres (earthenware vessel) which has Beli'ot but cannot be kashered, the status of a metal which absorbs and can release, or the status of glass which does not even absorb. Some are of the opinion that even though in theory they can be Kashered, nevertheless, we are afraid that one may not Kasher the plastic utensil in boiling water properly. The same would be true for dentures. Therefore, according to many authorities, dentures do absorb and cannot be Kashered. Additionally, some dentures do have a bad smell to them if not kept clean, refuting the words of the doctor quoted above.
Rav Ovadya Yosef’s three approaches have left us with a few Halachic challenges. In his first approach, we still had to work out the fact that some opinions hold a Keli Sheini is Mavli’a and Maflit. Even a liquid is as long as it's Yad Soledet Bo. Moreover, there is the issue of a Devar Gush. The second approach of Rav Ovadya is not consistent to modern day findings. The third approach may be problematic in a practical way: many have metal dentures and many authorities hold that plastic absorbs, so for one reason or another it cannot be Kashered.
We can answer the first Halachic issue of Rav Ovadya simply by saying that we don't rule like those who say a Keli Sheini at the minimum is able to be Mavli’a and Maflit. As the Aruch HaShulchan (105:19-20) writes, most authorities do not follow this opinion at all, and even if the liquid is Yad Soledet Bo, it cannot transfer Ta’am in a Keli Sheini. Furthermore, according to the stringent opinions, our case of fillings and dentures is a case of She’at HaDechak. Fillings are a She’at HaDechak because it is impractical to Kasher one’s mouth all the time. As Rav Shmuel Wosner, a prominent Posek in Bnei Brak, writes in his work Sheivet HaLevi (1:148), it is something the “Rov HaTzibbbur Ein Yecholim La’Amod,” “The majority of the congregation cannot stand.” Rav Ovadya explains that dentures are a She’at HaDechak because it is impossible to Kasher them without destroying them. Dentures are also a Hefsed Merubah (great loss), since buying many pairs are expensive. Therefore, even according to the stringent opinions, the Taz (105:4) writes that in a case of Makom Chashuv (important place) or Hefsed Merubah (major monetary loss), we can be lenient and rely on those opinions who hold that a Keli Sheini (even if the liquid is Yad Soledet Bo) cannot transfer Ta’am. In terms of Chameitz, we can be lenient as well due to Hefsed Merubah.
As presented earlier, Rav Ovadya pointed out that the Aruch HaShulchan (447:11) and the Mishnah Berurah (447:26) write that even though by Pesach we are more Machmir with regards to a Keli Sheini, in a case of a Hefsed Merubah and Simchat Yom Tov, we can fall back on the regular Halachah. So too, by fillings and dentures we can say that since they are a Hefsed Merubah one cannot really afford to keep paying for new dentures or fillings, and we can be lenient and rely on the regular rule that a Keli Sheini does not transfer Ta’am by a liquid even if it is Yad.
Additionally, the Minchat Shlomo points out in the matter of Chameitz that there are many opinions that hold that the Rama is Machmir that a Keli Sheini does absorb Ta’am only when one can Kasher the Keli. If the Keli cannot be Kashered, then the normal rule applies. So the Minchat Shlomo writes that here too, it is impossible to Kasher fillings, and in order to Kasher them we should rely on the normal rule that a Keli Sheini is not a Mavliah. Even more so, one can claim that the mouth is really a Keli Shlishi.
We can answer the Devar Gush problem the same way. Concerning a Devar Gush, the Aruch HaShulchan (94:32) writes that in a Hefsed Merubah or BeDi’eved, one can rely on the Rama. Therefore, since fillings are a Hefsed Merubah we can be lenient and rely on the opinions who are lenient. Additionally, the Shevet HaLevi (1:148) quotes the Chetam Sofeir (Yoreh Dei’ah 95) who writes that in a difficult situation one can be lenient by a Devar Gush. With respect to Pesach, R’ Joseph ben Meir Teomim, notable for his work Pri Megadim, notes (Orach Caim, Eshel Avraham 451:38) that in terms of a significant loss we are lenient for a Devar Gush in a Keli Sheni even for Pesach. Even though it is possible for someone to taste or eat something from a Keli Rishon, perhaps we can rely on the idea that the mouth itself is a Keli. Therefore, the mouth is a Keli Sheini and one can rely on the leniencies just expressed.
In regards to whether or not plastic absorbs and is ‘Kasherable’: Since this situation is a Sha’at HaDechak and Hefsed Merubah we would need to follow the lenient opinions that they either don't absorb, or they absorb and can be Kashered. We would also need to follow the opinions that hold that since one is not concerned that the utensil will be damaged when it is used as a Keli Rishon, for Kashering as well the individual will have no fear of Kashering it in a Keli Rishon. Additionally, since dentures are used to sip boiling hot tea, there is no worry that the person will be nervous when they Kasher the denture with boiling hot water.