Mishnah 2 in the third chapter of Maseches Menachos turns our attention to additional things that can go wrong in bringing a minchah, beyond the four essential avodos discussed earlier.
The guiding principle in our sugya:
The pesukim require many details in the bringing of the menachos. If the Torah mentions a requirement only once, it is a mitzvah to do it lechatchilah, but if it was not done it is not indispensable and the offering is not disqualified after the fact. If, however, the Torah repeats the command a second time, the matter is le'ikuva, meaning essential, and if it was not done the offering is disqualified even bedieved. In its first part the Mishnah lists a series of stages that are supposed to be performed with the minchah, and rules that although failing to do them detracts from fulfilling the mitzvah properly, the minchah is nevertheless valid after the fact.
Since the Mishnah uses few words, and does not even list the stages in their chronological order, we will first describe the entire process from the outside, and only afterwards look at the brief list inside.
The order of preparing the minchah:
The minchah is prepared inside a kli shareis - the sanctified mixing bowl. Every minchah consists of an issaron of flour (almost a gallon) and a log of oil (about half a liter), and these are its stages in most menachos:
A little oil is placed at the bottom of the mixing bowl.
The flour is added.
A second pouring of oil is added and it is mixed - this is the belilah. Sometimes even the second pouring of oil that precedes the mixing is called belilah.
The remainder of the oil is added in a third pouring - this is the yetzikah, through which all of the oil is completed.
If it is a raw minchah, and a non-kohen prepared it, it is handed over to a kohen.
Hagashah - the kohen brings the bowl to the southwest corner of the mizbe'ach.
Kemitzah, and afterwards burning the kometz on the mizbe'ach - or burning the entire minchah, in those menachos that have no kemitzah.
Melichah - before the burning the kometz is salted, and it goes up onto the mizbe'ach together with the salt.
The cooked voluntary menachos:
There are five types of voluntary minchah, and four of them are cooked in some manner and are not batter or raw dough: two are fried - machavas and marcheshes; and two are baked - challos and rekikin, which are not chametz-like (a challah resembles a Sephardic matzah, and a rakik resembles a basic Ashkenazic matzah). After they come out of the oven or the pan, pesisah is performed on them: the loaves are folded, broken and crumbled into pieces, ideally each the size of a kezayis. There is a discussion as to exactly where pesisah fits into the order of the process.
With rekikin the order is different: instead of the belilah, a little oil is placed in them at the outset (and there is a dispute among the Rishonim about this), and after they have been kneaded with water and baked in the oven, meshichah is performed on them - the oil is smeared onto the rekikin and is absorbed into them.
What is actually indispensable:
The Mishnah rules that if any of these were not done, the minchah is not disqualified. In practice, however, one or two of them are indispensable, and therefore the Mishnah is reinterpreted:
Yetzikah (pouring) - one is obligated to pour a little oil at the end. Therefore, when the Mishnah says that if he did not pour it is valid, the meaning is that a kohen did not pour, but someone who is not a kohen did.
Melichah (salting) - there is a dispute in the Gemara whether it is indispensable after the fact. According to the opinion that it is indispensable, here too the Mishnah is to be understood as meaning that a kohen did not put on the salt, but someone who is not a kohen did.
The wording of the Mishnah and its details:
"lo yatzak" - the third and final pouring of oil was not performed. As stated, this is not to be taken literally; rather, a kohen did not pour.
"velo balal" - the second pouring of oil, the one that precedes the mixing in the vessel, was not performed. It is worth clarifying: we are speaking of a case in which all the oil was placed, either in the first pouring or in the last, and only the middle stage was skipped. But if the required log of oil is lacking, it is certainly invalid even after the fact.
"lo pitet" - he did not crumble the minchah by folding it in order to break it into pieces the size of a kezayis, or the folding did not crumble it at all. The Bartenura points out a practical problem: at the very least part of it must be crumbled in order to take the measure of a kometz, for in the menachos that require crumbling, which are voluntary menachos, only one measure of a kometz goes up on the altar and the rest is eaten by the kohanim, and one cannot bring up a whole loaf.
"lo malach" - he did not salt the kometz that goes up on the altar. As stated, there is a dispute in the Gemara, and according to the opinion that it is indispensable, we are dealing with an unusual case in which someone who is not a kohen did it.
"lo henif" - only two menachos require waving: the minchas ha'omer and the minchas kena'os brought with the sotah. The waving is done like the movements of the lulav, to the four directions and upward and downward. If he did not wave - after the fact it is valid.
"lo higish" - the kohen did not bring the vessel, before the kemitzah, to touch the southwestern corner of the altar.
"o shepitesan pesim merubos" - he did crumble it, but not in the proper measure.
"velo meshachan" - he did not spread the oil on the wafers and skipped this stage.
It is worth noting that in the Bartenura's comment on "lo henif" the text reads "in the minchas chotei or the minchas kena'os." This is almost certainly a printing error that crept in, since the minchas chotei does not require waving, and it is the minchas ha'omer that does.
Regarding "pesim merubos" there are two approaches in the commentaries: either the pieces are too large, or they are numerous and therefore too small. The Bartenura explains that large pieces were made. At first glance this is logically puzzling, for the Mishnah has already taught that if he did not crumble at all it is valid, so what is the novelty in teaching that if he crumbled but not sufficiently it is valid? The answer is that one might have thought that when they are whole, loaves just as they were meant to be, that is preferable to crumbling done improperly. Others explain that "pesim merubos" refers to small pieces, that is, if he crumbled excessively until they became too small, after the fact it is valid. In any case, the Rema hints in halachah that lechatchilah it must be folded and crumbled into pieces the size of a kezayis, and if they are too large or too small - it is valid after the fact.
In all these cases the ruling is that it is valid after the fact, subject to the qualification described above regarding "lo yatzak" and perhaps also "lo malach". This concludes the first part of the Mishnah.
The second part: a kometz that became mixed:
The second part of the Mishnah is an entirely new topic, and indeed in the Babylonian Talmud it constitutes a separate mishnah. Here the discussion opens with the question of the law of a kometz that became mixed with other things. The cases before us are those in which the kometz became mixed with items that in any case go up entirely on the altar, and therefore there is no real problem. The words of the Mishnah: "nis'arev kumtzah bekometz chavertah, beminchas kohanim, beminchas kohen hamashiach, beminchas nesachim - kesheirah".
"bekometz chavertah" - a kometz was taken from minchah A, and it became mixed with the kometz taken from minchah B. Both go up on the altar and both are valid.
"beminchas kohanim" - a kohen who brought a minchah; the rule is that the menachos of kohanim are burned entirely. Therefore, if the kometz became mixed with a kohen's minchah, the whole of it goes up on the altar.
"beminchas kohen hamashiach" - this is the minchah of the Kohen Gadol, the minchas chavitin, which the Kohen Gadol brings every day and which is made into twelve loaves: half in the morning and half in the afternoon. It too is burned entirely.
"beminchas nesachim" - the accompanying menachos that come with every olah and every shelamim, which were discussed at the end of the previous chapter. They too are burned entirely and have no kemitzah.
In all of these, whether what became mixed in is a kometz or has no kemitzah at all, everything is burned on the altar and it is valid. Admittedly "kesheirah" is stated in the singular, because the discussion centers on the kometz, but in practice both offerings under discussion - minchah A and minchah B - are valid, and their owners have fulfilled their obligation.
A thick mixture and a loose mixture:
In two of the offerings on this list the texture of the minchah is different, and they are especially oily. The ordinary minchah is measured as an isaron of flour and a log of oil, that is, roughly one eighth oil and seven eighths flour, and when it is mixed a thick dough results. By contrast, the minchas nesachim that accompanies an olah or a shelamim, when the offering is a goat or a lamb in its first year, is measured as an isaron of flour not with one log but with three logim - what Scripture calls "revi'is ha'hin", since a hin is twelve logim and a quarter of it is three. This is three times as oily, and it is what the Sages call belilah rakah (a loose mixture), as opposed to belilah avah (a thick mixture). The minchah of the Kohen Gadol also has a loose mixture, thin like batter and full of oil.
Rabbi Yehudah disagrees on this very point. He too accepts the principle that if everything in the mixture goes up on the altar, it is all valid; but in his view there is a problem when a loose, oily batter becomes mixed with a kometz of thick batter: the abundant oil is absorbed into the kometz until the kometz may end up mostly oil and only partly flour, and at that point nullification by majority takes effect, and the flour loses its status and its identity in the face of the majority.
Therefore, says Rabbi Yehudah, when the kometz of a thick-batter offering became mixed with a Minchah that is entirely loose batter, the kometz loses its identity and the first Minchah does not count for its owner, even though it is placed on the fire. The second offering, the libations or the chavitin, is valid, since all of it goes up on the altar. In the words of the Mishnah: "Rabbi Yehudah omer, b'minchas kohen mashiach u'minchas nesachim - pesulah, shezo bilalasah avah v'zo bilalasah rakah, v'hen bol'os zo mizo" - Rabbi Yehudah says: with the Minchah of the anointed Kohen and the Minchah of libations it is invalid, because this one's batter is thick and this one's batter is loose, and they absorb from one another.
The Sages disagree. They do not deny the principle of nullification by majority; it is a valid principle, and on its own terms it would apply here as well. But there is a separate principle: "olin ein mevatlin zeh es zeh" - items that go up on the altar do not nullify one another, and neither one cancels the status of the other. Even though a minority and a majority are mixed together here, nothing loses its identity, and everything that goes up on the altar retains its identity. Therefore, even if the kometz was absorbed into the oil, there is no nullification here, and the kometz that went up has counted for its owner.
The halachah: like the first Tanna and like the Sages - the mixture of the kometz together with the Minchah of libations is placed on the altar and it is all valid. According to Rabbi Yehudah the kometz is nullified and invalid, so the one who brought the Minchah has not fulfilled his obligation, while the one who brought the libations has, since the libations are valid. But the halachah follows the Sages, that both have fulfilled their obligation, because both are burned on the altar, and the principle of "olin ein mevatlin zeh es zeh" establishes that there is no nullification by majority among items whose law is to be burned on the altar.