Talmud - Pesahim 40b פסחים מ׳ ב׳

that his mother would bring him wheat in a trough. In other words, she would guard the wheat grains from when they were harvested by placing them in vessels and guarding them until Passover.

The Gemara relates that there was a certain boat carrying wheat, which capsized before Passover in the Ḥishta River. Rava permitted its owners to sell the recovered grain to gentiles before Passover.

Rabba bar Levai raised an objection to the opinion of Rava from a baraita: With regard to a garment in which diverse kinds, a prohibited mixture of wool and linen, has been lost, i.e., a wool garment into which a linen thread was sewn or vice versa, one may not sell it to a gentile; and one may not even fashion it into a saddlecloth for a donkey. It is prohibited to do so lest one remove a piece of this garment and sew it onto his own clothing. However, one may fashion it into a shroud for a dead body, as there is no concern that he will remove it from the dead.

The Gemara clarifies this issue: What is the reason that one may not sell it to a gentile? Is it not due to the concern that the gentile will resell it to a Jew? Since the mixture of wool and linen is not visible, it is possible for a Jew to use this cloth unawares. The same concern applies to grain: It is not apparent that the grain that capsized in the river is prohibited. It should therefore be prohibited to sell this wheat to gentiles, lest they resell it to Jews.

Rava reconsidered and then said: He should sell this wheat one kav at a time, i.e., in small measures, each to a different Jew, but not to any one Jew in large quantities, so that all of this wheat will be used before Passover. By selling it in this manner, all the grain will be used quickly and no one will unwittingly eat these leavened grains on Passover.

The Sages taught: One may not stir flour into a pot of food on Passover to absorb the foam that has accumulated during the cooking process. And one who wishes to stir flour should add the flour and afterward add vinegar, which will prevent the flour from becoming leavened. And some say: One may even add vinegar and afterward add the flour, as vinegar prevents flour from becoming leavened even after the flour is diluted in water.

The Gemara asks: Who is the tanna whose opinion is introduced by the phrase some say?

Rav Ḥisda said: It is the opinion of Rabbi Yehuda, as we learned in a mishna: With regard to a stew pot or a pot of food that one removed from the fire when it was seething, one may not add spices to them on Shabbat. However, one may add spices to a dish or to the large plate into which the food is poured from the pot. Rabbi Yehuda says: One may add spices to any food that has been removed from the fire, except to a dish that contains vinegar or brine, as this food is considered as though it were still seething, due to the pungency of the vinegar or brine. Since Rabbi Yehuda maintains that vinegar has the same effect as boiling, he would agree that vinegar, like boiling water, prevents flour from becoming leavened.

The Gemara asks: And let us establish the opinion of: Some say, in accordance with the opinion of Rabbi Yosei. As we learned in a mishna: Rabbi Yosei says, with regard to wheat grains that were soaked in water: One should soak them in vinegar, and this vinegar will cause the wheat to contract and prevent it from becoming leavened.

The Gemara answers: When we learn the opinion of Rabbi Yosei, this applies only to a situation where the vinegar is in its pure, unadulterated form, in which case its pungency prevents the wheat from becoming leavened. However, if the vinegar is added by means of a mixture, no, Rabbi Yosei’s statement does not apply to a case of this kind.

Ulla said: In both of these cases, whether the vinegar is added first or afterward, its use is prohibited, as one must avoid scenarios that might lead to a prohibition, as per the well-known adage: Go around, go around, and do not approach the vineyard, they say to the nazirite. Since a nazirite is prohibited from drinking wine and eating grapes, it is preferable for him to avoid a vineyard entirely. A similar principle applies to other prohibitions.

The Gemara relates: Rav Pappi permitted the cooks [burdikei] of the household of the Exilarch to mash roasted grains into a pot of food, to dissolve the accumulated foam. Rava said: Is there anyone who permits this matter in a place where servants are found? Servants are unlikely to be careful with regard to these prohibitions. They will use raw flour for this purpose, which will lead to a violation of the prohibition against leavened bread on Passover. Some say that Rava himself would add roasted grains into his own pot.

MISHNA: One may not add flour to ḥaroset, a seasoned, pungent food, or to mustard, to dull the sharp taste. In both cases, the pungency of these foods might accelerate the leavening of the flour. And if one added flour to either of these, the mixture may be eaten immediately before it is leavened; and Rabbi Meir prohibits this, lest the food be leavened immediately.

The mishna continues: One may not boil the Paschal lamb in ordinary liquids or in fruit juices, as the Torah explicitly states that it must be roasted. However, one may baste it while it is roasting and dip it into liquid while eating it.

The tanna further states: Water that has been used by a baker for cooling his hands or washing dishes should be poured out, because this water leavens the dough, as the water probably contains a small quantity of flour and dough.

GEMARA: Rav Kahana said: The dispute between Rabbi Meir and the Rabbis concerns a case where one adds flour to mustard, which is extremely pungent and will not leaven the flour immediately. But in a case where flour is added to the less pungent ḥaroset, which will leaven the flour quickly, everyone agrees that the mixture must be burned immediately.

And that opinion was also taught in a baraita: One may not add flour to ḥaroset, and if one did add flour it should be burned immediately. With regard to flour that was added to mustard, Rabbi Meir says: It should be burned immediately, and the Rabbis say: It should be eaten immediately, before it is leavened. Rav Huna, son of Rav Yehuda, said that Rav Naḥman said that Shmuel said: The halakha is in accordance with the opinion of the Rabbis concerning this issue. Rav Naḥman bar Yitzḥak said to Rav Huna, son of Rav Yehuda:

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

Pesachim 40b examines selling water-damaged wheat before Passover to gentiles and the risk of leaven mixtures reaching Jewish buyers unnoticed.