Talmud - Pesahim 30b פסחים ל׳ ב׳

one may not smear the inside of an oven with the fat tail [alya] of a sheep, because it is meat. And if one did smear it over the oven, then all of the bread baked in it is prohibited, lest one accidentally eat this bread with milk. However, this applies only until one kindles the oven and burns off this fat. The Gemara infers from this baraita that if the oven was kindled afterward then it is permitted in any case. This would seem to present a conclusive refutation of the statement of Rava bar Ahilai who maintains that the bread cooked in this oven is prohibited forever, even after the oven is rekindled. The Gemara concludes: Indeed, this is a conclusive refutation of his opinion.

Ravina said to Rav Ashi: Since the statement of Rava bar Ahilai was refuted, why did Rav say that pots that were used for leavened bread on Passover should be broken? Presumably, their status could be remedied in the same way as was that of this oven, by heating them on a fire until the flavor of the leavened bread absorbed in them was removed. Rav Ashi said to him: There is a distinction between these two cases. There, it is referring to a metal oven, which can be cleansed through an additional kindling, while here, it is referring to an earthenware pot, where additional kindling is insufficient, as the earthenware has the capacity to absorb more of the flavor of the leavened bread and it cannot be purged by fire.

If you wish, say instead that both this, the oven, and that, the pot, are earthenware, but that the following distinction applies. This, the oven, is kindled from the inside, and as the fire is kindled inside the oven itself, it consumes the absorbed flavor of the leavened bread. While that, the pot, is kindled from the outside, such that the flavor of the prohibited material absorbed in the pot is not purged by the fire. And if you say, so too here, in the case of the pot, he should perform the kindling procedure on the pots from the inside to remove that which has been absorbed, this is not reasonable. Presumably, the owner of the pot will be concerned lest it burst if he makes the pot too hot. Therefore, he will not use sufficient heat to ensure that the leavened bread that has been absorbed will be completely purged.

The Gemara concludes: Therefore, based on this principle, this griddle made from earthenware tiles that was used to bake bread is a type of oven where the kindling is from the outside and therefore prohibited. But if he fills it with burning coals, then it seems well and it can be used afterward. Because this vessel is often subject to a high level of heat, the owner will not be concerned that it will break when heated.

Ravina said to Rav Ashi: With regard to these knives, how do we prepare them for use during Passover? Rav Ashi said to him: For me, personally, we craft new ones. Ravina said to him: It works out well for Master, as you are able to afford new knives. However, what should one who is unable to purchase new knives do? He said to him: I was speaking of making them like new by thoroughly cleaning them in the following manner: One should cover the wooden handles in mud, so that they will not be burned, and heat the metal with fire until it is white-hot. And then I place the handles of the knives in boiling water in order to remove anything that had been absorbed into the wood. And the halakha is that with regard to both this, the blade, and that, the handle, it is sufficient to immerse them in boiling water, so long as this water is still in a primary vessel. The water must still be in the original pot in which it was boiled and not poured from another pot.

Rav Huna, son of Rav Yehoshua, said: A wooden ladle should be purged in boiling water in a primary vessel in order to remove the flavor of the forbidden food that it absorbed. The Gemara states: He holds in accordance with the principle: As it absorbs the flavor of the forbidden substance, so it emits it. The same cooking method and level of heat that caused the flavor of the forbidden substance to be absorbed in the vessel suffices to discharge the flavor of that substance from the vessel. Therefore, a ladle that absorbed flavor of leavened bread from a pot of boiling water which was over a fire will discharge the flavor of leavened bread once it is placed in the boiling water again.

They raised a dilemma before Ameimar: Concerning certain glazed [konya] earthenware vessels, what is the halakha with regard to using them during Passover? The Gemara explains: With regard to green vessels, the dilemma need not even be raised, as they are certainly prohibited as their coating does not prevent them from absorbing the flavor of leavened bread. Let the dilemma be raised with regard to black and white vessels: What is the halakha here? And furthermore, the dilemma need not be raised when they have cracks; as the leavened bread will remain stuck in these cracks, they are certainly prohibited. Let the dilemma be raised with regard to smooth vessels: What is the halakha in that case?

Ameimar said to him: I saw that some of the liquid is expelled [demidayeti]? from the outside of the vessel. Apparently they absorb and are therefore prohibited, as they cannot be prepared for use on Passover through cleansing, and the Torah testified about earthenware vessels that when they absorb the flavor of a prohibited substance, they will never leave their defective status and they remain permanently prohibited. The Torah states that a person may cleanse other vessels by scouring and rinsing them, whereas it states that earthenware vessels must be broken.

The Gemara asks: What is different about wine used for a libation, with regard to which the halakha of earthenware vessels is more lenient? As Mareimar taught: A glazed earthenware vessel is permitted whether it is black, white, or green if it was used to store wine belonging to gentiles. Any wine that came in contact with gentiles is suspected of having been poured as a libation offering to idolatry. And if you say that it is possible to distinguish between the prohibition of wine used for a libation, which is a rabbinic prohibition, and that of leavened bread, which is forbidden by Torah law, this is difficult, as all ordinances that the Sages instituted, they instituted similar to Torah law. Once they have declared that this item is prohibited, the principles applicable to Torah prohibitions apply to it as well. Ameimar said to him: The distinction between the two cases is that with regard to this vessel, which is used for cooking during Passover, its primary use is with hot foods, and therefore the flavor of the leavened bread has become absorbed within its walls. But with regard to this vessel, which is used to store wine, its primary use is with cool liquids, which are not absorbed to the same degree.

The Gemara continues discussing the ways that a vessel must be cleansed so that it can be used during Passover. Rava bar Abba said that Rav Ḥiyya bar Ashi said that Shmuel said: Any vessel that was used for leavened bread only while cool can be used for matza, because no flavor of the leavened bread was absorbed by the vessel. The exception to this rule is the leaven container where the yeast was stored, since its leavening is more potent, and it can be assumed that the flavor from the yeast has entered the walls of the vessel even without heat. Rav Ashi said: And the spice container, in which potent spices that contained flour were stored, has the same status as the leaven container whose leavening is potent.

Rava said: With regard to certain bowls of Meḥoza, since it is common to knead leavened bread in them and then store the leavened bread in them, they are considered to be like a leaven container whose leavening is potent. The Gemara asks: Why did Rava find it necessary to make this statement? Isn’t it obvious that these bowls are the same as a leaven container? The Gemara answers: Lest you say that since these bowls are spacious, the air dominates them and they do not absorb the leavened bread in the same way as does a leaven container, therefore, he teaches us that no such distinction applies.

MISHNA: If a gentile lent money to a Jew, and the Jew gave him leavened bread as collateral until after Passover, and after Passover the gentile retains this leavened bread in lieu of payment, then one is permitted to derive benefit from this leavened bread. Since the leavened bread was retained by the gentile based on the transfer that took place prior to Passover, the leavened bread is considered to have belonged to the gentile during Passover. Whereas if a Jew lent money to a gentile, and leavened bread was given as collateral during Passover in the same manner as in the previous case, then after Passover it is forbidden to derive benefit from this leavened bread. Since this leavened bread was considered to be in the Jew’s property during Passover, it is forbidden to derive benefit from it afterward.

GEMARA: It was stated that the amora’im disagree about the rights of a creditor with regard to collateral. Abaye said: He retroactively collects the property. In a case where the creditor had a lien on the property of the debtor and the debtor defaults on the loan, it is considered as if the creditor acquired rights to the collateral at the time of the loan and not at the time of collection. And Rava said: This is not the case, but rather, he acquires the collateral from that point forward, and has rights to the collateral only from the time that the loan was due. This dispute has ramifications for the status of the property, and actions undertaken with regard to it, during the intervening period. The Gemara sets several limitations on the scope of this dispute: Anywhere that the debtor consecrated or sold the field that was serving as collateral, everyone agrees that the creditor can come and seize this property and override the sale, because its status as collateral preceded its sale.

Traduction : The William Davidson digital edition of the Koren Noé Talmud, with commentary by Rabbi Adin Even-Israel Steinsaltz.

Pesachim 30b examines whether ovens or pots absorbing forbidden fat or leaven can be purified by fire, contrasting metal and earthenware materials.