The Mishnah continues to discuss the secondary parts of Terumah produce, and the question of whether the laws of Terumah apply to them. Here the subject is seeds. Seeds that are not fit for eating at all, such as an apricot pit, are not even part of the discussion - they certainly have no status of Terumah. But there are seeds that are edible for anyone who wants them, such as apple seeds; some people eat the entire apple, core and all, and these seeds are therefore considered a type of food.
With seeds like these, which stand on the borderline of edibility, their status depends on the intention of the kohen:
If he set the seeds aside in order to eat them later - they are food, and all the restrictions of Terumah apply to them.
If he threw them out - they are nothing more than garbage seeds, and their status as Terumah has lapsed. For this reason even a non-kohen may eat them.
The bones of sacrificial meat:
That same reasoning applies to the bones of sacrificial animals. The meat of a korban must be eaten - there are offerings eaten only by kohanim, and there are offerings eaten by non-kohanim as well - and every type of sacrificial meat has a fixed time for eating: some may be eaten for one day, and some for two days. Once the time has passed the meat becomes forbidden to eat, and it is called 'nossar', and one who eats it bears the severe punishment of kareis.
What, then, is the law regarding the bones of the animals that are offered? Bones that are entirely unfit for eating are not food, and there is nothing to discuss about them. But softer bones, such as cartilage or the soft part of the marrow bone, are edible for anyone who wants them. The question is whether such a borderline bone is considered meat to the point that one who eats it after the time would be liable for nossar. The answer follows the same principle: as long as he did not throw the bones out and kept them for later eating, they remain subject to all the restrictions of ordinary sacrificial meat; once they have been thrown out as garbage, the restrictions have lapsed and they are nothing but refuse.
The waste products of milling:
Here the Mishnah moves to a new subject: the waste products created in processing grain. We must distinguish between two separate stages in processing wheat, each of which produces waste:
Threshing: the stalks are laid out on the threshing floor, and an animal walks in circles dragging a heavy board that separates the wheat from the chaff. The chaff is completely inedible, and is fit only as animal feed, and therefore it is not discussed at all.
Grinding and sifting: after threshing, winnowing and sorting, the wheat kernels are gathered and stored. When one wants to make bread, he grinds them, and the resulting flour is passed through a sieve. The sifting process separates the fine flour from the bran, which one does not wish to eat.
The wheat kernel itself has several parts:
The endosperm - the main body of the kernel, which yields the bright white flour.
The germ - found inside the kernel, extremely nutritious, but it does not leave a perfectly white flour, and so some people sift it out even though it is fine.
The bran - the coating around the wheat kernel, which is coarser. Whole wheat flour includes it, while flour that is not whole wheat sifts it out.
The coarse bran - the coarsest material, hairy and fibrous, found on the outer part of the kernel, and completely inedible.
The same logic we have seen until now applies here as well. The coarse bran, that coarse fibrous husk, is not food at all - just as we said regarding bones that are not food and fruit stems that are not food. In the times of Chazal they would even save the coarse bran and use it as an exfoliant, rubbing it on the skin to remove dead skin. For this reason the coarse bran does not take on the status of Terumah, since it is inedible and is not food.
The subin, by contrast, is fully edible. In our times it has even become fashionable and is considered nutritious and healthy, while in the times of Chazal people preferred not to eat it and asked for white flour - but edible it certainly is. Its status therefore depends on how fresh the wheat is.
"Shel chadashos" and "shel yeshanos":
When we speak of "new" and "old" wheat, one might think of last year's crop and this year's crop, which are divided by the bringing of the Omer. That is not the intent at all. The distinction here is between fresh wheat, just harvested, and wheat that is no longer fresh.
Wheat is cut in the harvest season, around Shavuos at the beginning of the summer, and it then sits in the field all summer long to dry out. At Sukkos, the festival of ingathering, the dried wheat is brought in. Once it has dried thoroughly it is excellent for grinding; but wheat that has just been cut is still moist inside, and when it is ground the endosperm - the white flour - sticks to the bran because of the moisture. In such a case the subin contains a substantial amount of Terumah, real food that is fit to be eaten.
New wheat - harvested within the last thirty days and not properly dried. The subin left over from grinding it has endosperm, edible flour, stuck to it, and it is therefore forbidden to a non-kohen, since it is still Terumah.
Old wheat - more than thirty days have passed and it has dried out completely. The subin left over in the sifting process is dry and has no flour clinging to it, and once it has been discarded as something that is not flour it is permitted to a non-kohen, since it no longer has the status of Terumah.
In the words of the Mishnah:
"HaMurson mutar" - that coarse, fibrous material which is not food at all, and carries no Terumah restrictions; a non-kohen who ate murson from wheat of Terumah bears no liability whatsoever.
"HaSubin shel chadashos asuros" - the inner husk surrounding the wheat kernel, when the wheat was harvested within thirty days or less, is forbidden.
"V'shel yeshanos mutaros" - after thirty days, once the wheat has aged and dried out, that subin is permitted to a non-kohen, for it is no longer considered food.
"V'noheg biTerumah k'derech shenoheg b'chullin":
This is a new point, though it is connected to the previous one. It is forbidden to destroy food of Terumah, and the question naturally arises how exacting a person must be when eating Terumah so that nothing is lost - not to leave a drop behind, not to lose remnants in the grinding machinery, and the like. To this the Mishnah says: "V'noheg biTerumah k'derech shenoheg b'chullin" - a person's ordinary standards in consuming food are what determine the matter. Whatever is not considered waste with chullin is not considered waste with Terumah.
"HaMesales kav o kavayim l'se'ah":
In light of this, the Mishnah discusses someone who sifts his flour through the very finest sieve in order to produce "soles," which is apparently similar to today's white flour and was regarded as an especially fine food. In the times of Chazal they were not able to grind wheat as finely as we do today, and so not everything passed through the final sifting; one who does this leaves behind a great deal of flour, entirely fit to eat, which is not subin at all but genuine flour. The question is: since he has no intention of eating this flour, is it considered flour or refuse?
The Mishnah rules that it is flour and it is food. A person is free to conduct himself by high standards, but he may not destroy the flour and waste it while it is perfectly fit to be eaten; he is obligated to safeguard it like any Terumah, and it must not go to waste.
In the words of the Mishnah: "HaMesalet kav o kavayim li'se'ah" - from every se'ah that goes into the sifting process, only one kav or two come out fit for eating. As we recall, a se'ah contains six kavin (picture it this way: a six-pack of two-liter bottles, each bottle being one kav), so it turns out that the sifter is left with four or five kavin of perfectly good flour.
"Lo ye'abed es hashe'ar" - he is not permitted to destroy the four or five kavin that did not pass through the sifting. "Ela yanichenu bemakom hamutzna" - he must place them in a protected spot until they spoil on their own. Once they spoil he may of course dispose of them, but until then it is his responsibility to guard them from destruction and from tumah.