(Rav Yosef): One may not Cholet two grains of wheat at the same time - perhaps one will be in a crack of the other, and the heat of the water will not reach it from all sides [to Cholet properly], and it will become Chametz.

(Abaye): One may not roast two ears of grain at the same time - perhaps juice will leave one and be absorbed in the other, and it will become Chametz.

Objection (Rava): If so, even one should be forbidden - perhaps juice will leave one end and be absorbed in the other end, and it will become Chametz!

(Rava): Rather, we are not concerned [in either case] because Mei Peiros cannot cause Chimutz.

Abaye retracted [and permitted for a different reason], because nothing become Chametz while falling:

(Abaye): If grain was parched in a jug in an oven:

If the mouth faces down [so juice that exudes will fall out], it is permitted;

If the mouth faces up, it is forbidden.

(Rava): In both cases it is permitted - Mei Peiros do not Mechametz.

(Beraisa): One may not Loses barley (soak it before removing the bran) during Pesach; if one did:

If the kernels split, they are forbidden; if not, they are permitted.

R. Yosi says, [if one sees them inflating] he soaks them in vinegar - this impedes Chimutz.

(Shmuel): The Halachah does not follow R. Yosi.

(Rav Chisda): The Beraisa does not mean that they truly split - rather, they would split by themselves if put on top of a barrel of wine [on account of the smell; Tosfos - if put on top of a porous Keli on which grain is parched, they would split on account of the heat].

(Shmuel): It means that they truly split.

A case occurred - Shmuel was lenient, because they had not truly split.

(Rabah): A Ba'al Nefesh (one who goes beyond the letter of the law; alternatively - fears Shomayim) will not Loses.

Question: The Beraisa forbids everyone to Loses barley during Pesach!

Correction: Rabah means that a Ba'al Nefesh will not Loses even wheat, which is hard [and does not become Chametz so quickly. On 48A, Tana'im argue about whether dough of wheat or barley is more prone to become Chametz - perhaps all agree that Lesisah is more prone to Mechametz barley.]

Rav Nachman: One who heeds Rabah eats moldy (i.e. inferior) Matzah! They Loses in the houses of Rav Huna and Rava bar Avin!

(Rava): It is forbidden to Loses.

Question: The Beraisa forbids to Loses barley - this implies that one may Loses wheat!

Answer: The Beraisa teaches a bigger Chidush:

Not only wheat, which has cracks, is forbidden - rather, even barley, which is smooth, is forbidden.

Retraction (Rava): It is permitted to Loses:

(Beraisa): One is Yotzei with bread that is clean or coarse.

The only way to make clean bread is through Lesisah!

Question (Rav Papa - Beraisa): Flour and Soles of Nochrim - that of villages is Tahor; that of cities is Tamei.

That of villages is Tahor because Lesisah was not done - nevertheless, it can be Soles (from which one can make clean bread)!

Answer (Rava): No, the Beraisa is Metaher only flour of villages (Soles is found only in the cities, where they Loses).

Question (after Rava left - Rav Papa): R. Zeira taught that we do not Loses wheat of Menachos, even though Soles is required!

Retraction (Rava): It is a Mitzvah to Loses - U'Shmartem Es ha'Matzos - if we need not Loses, why must we guard the Matzos?

It cannot refer to Shmirah during kneading - this is not considered Shmirah!

(Rav Huna): One may gorge himself on dough of Nochrim [on the first night], as long as he eats a k'Zayis of Matzah [of Yisraelim] at the end. (The dough was baked afterwards - otherwise, one is not Yotzei even with a Yisrael's, for it is not Lechem! Rashi - the Nochri made the dough, the Yisrael can see that it is not Chametz; Ritva - a Yisrael supervised that it was done properly - some say that Shimur of a Yisrael while the Nochri kneads would suffice.)

Inference: The Matzah must be at the end [when he eats it with Pesach, when satiated, and intends to fulfill the Mitzvah], not at the beginning - the Nochri dough is invalid, because it was not Shamur.

Question: He could Shomer it after it was baked!

Answer: We must say that Shmirah must be from the beginning.

Question: Perhaps Nochri dough is invalid because it was not Shamur from when this is necessary (when it became wet) - but it suffices to Shomer from this time, i.e. of kneading!

In spite of this question, Rava did not retract [from requiring Shmirah before kneading]:

Rava told people who were turning over sheaves [and tying them in bundles] to do so l'Shem Mitzvah.

This shows that he requires Shmirah from the beginning until the end.

Mar brei d'Ravina's mother was Shomer wheat for him in troughs from the beginning of the harvest.

A ship carrying wheat capsized in a river [before Pesach]; Rava permitted to sell the wheat to Nochrim.

Question (Rabah bar Livai - Beraisa): If Sha'atnez was lost in a garment, one may not make it into a saddle [lest he remove it and sew it into another garment] or sell it to a Nochri, but it may be used for shrouds (one may not benefit from shrouds).

He may not sell it to a Nochri lest the Nochri resell it to a Yisrael [since the Isur is not evident - similarly, we should be concerned lest the Nochri resell the wheat to a Yisrael, since the Chimutz is not evident. Normally, Yisraelim may buy wheat from Nochrim to use for Pesach - presumably, Nochrim are careful to keep it dry, lest it spoil!]

Rava retracted and commanded to sell it to Yisraelim, a bit to each buyer, in order that it would be finished before Pesach.

(Beraisa): One may not put flour in a Tavshil [off the fire. We explain like R. David; see note 25 in Appendix.]

It is permitted if he first puts in flour [while it is on the fire - this is Chalitah] and then vinegar;

Some say, he may put the flour in after the vinegar [which is always added after it is removed from the fire - even so, the vinegar is Cholet].

Question: Who is the latter Tana?

Answer (Rav Chisda): It is R. Yehudah (R. David - all the more so it is like Chachamim that argue with him, they say that even without vinegar a Keli Rishon cooks even off the fire, and hence is Cholet):

(Mishnah): If one removed a frying pan or pot from the fire, one may not put spices into it [on Shabbos];

One may put spices into a bowl (a Keli Sheni, into which food that was on the fire was poured).

R. Yehudah says, it is always permitted [to put spices in a Keli Rishon], unless it contains vinegar or brine [for then it can cook; it can also Cholet].

Question: We could establish it to be R. Yosi!

(Beraisa - R. Yosi): [If one sees the barley inflating] he soaks it in vinegar - this impedes Chimutz.

Answer: R. Yosi teaches that pure vinegar impedes Chimutz - we have no source that he says so about a mixture of vinegar [and a Tavshil].

(Ula): It is forbidden whether the vinegar was put first or last on account of 'Lech Lech Amrinan Nezira...' (a Nazir should stay far from a vineyard; similarly, everyone must distance himself from sin)!

Rav Papi permitted bakers of the Reish Galusa's house to thicken a Tavshil with Chasisi (Rashi - parched flour; Rif - Matzah meal; Tosfos - lentil flour).

Version #1 - Rava: Does one permit such a matter in a place where slaves [who are not careful about Mitzvos] are found?! (Perhaps they will use wheat flour that was not fully parched or baked!)

Version #2: Rava himself thickened a Tavshil with Chasisi.

(Mishnah): One may not put flour into Charoses (a dip containing vinegar - this is not the dip used at the Seder) or mustard - if one did so, he should eat it immediately [before it will become Chametz];

R. Meir forbids eating it (see note 26 in Appendix).

One may not cook Korban Pesach with liquids or Mei Peiros, but one may smear it with or dip it in them.

The water a baker uses [to cool his hands] must be spilled out, for it becomes Chametz.

(Gemara - Rav Kahana): They argue about flour put into mustard - but all agree that if flour was put into Charoses it must be burned immediately.

Support (Beraisa): One may not put flour into Charoses - if it was put, it must be burned immediately;

R. Meir says, if flour was put into mustard, it must be burned immediately;

Chachamim say, he should eat it immediately.