(Beraisa - R. Shimon): (If a Nazir was Safek Tamei Mes, and was unsure if he must perform Taharas Metzora... he brings a lamb a Log of oil, and stipulates: if I need to bring Asham Metzora, this is the Asham and the oil. If I need not bring it, this lamb is a Shelamim, and the oil is Nedavah.

We take a Kometz of oil, for perhaps it is Nedavah. We do seven sprinklings, for perhaps he needs Taharas Metzora. A full Log must remain, so we add more to restore the Shi'ur.

77a - Question: The Shirayim must be eaten, but oil was added after the Kometz was separated, and nothing permits the addition (and it is mixed with the Shirayim)!

Answer: We redeem the addition.

Chalah (Mishnah 3:8): If one took Se'or (sourdough, which ferments dough) from a dough from which Chalah was not taken and put in dough from which Chalah was taken, if he has Parnasah from elsewhere (another dough from which he can separate Chalah and exempt this), he separates according to the calculation. If not, he separates one Chalah on everything.

(Mishnah 10): Any amount of Tevel forbids b'Mino. Min b'Eino Mino, it forbids b'Nosen Ta'am (if it gives taste).

Rambam (Hilchos Bikurim 7:11): If one took Se'or from a dough from which Chalah was not taken and put in dough from which Chalah was taken, he brings a second dough so that combined with the Se'or, there will be a Shi'ur that obligates taking Chalah. He puts it in the dough from which Chalah was taken, and separates from the second dough a Shi'ur of Chalah for it and the Se'or, in order that he separates Min ha' Mukaf (right near the dough it exempts.). If he does not have another dough, the first dough becomes totally Tevel, and separates Chalah on everything, for any amount of Tevel forbids b'Mino.

Ri Korkus: A Chulin dough (i.e. from which Chalah was taken) is not a Hefsek between Tevel doughs (i.e. from which Chalah was not taken). Our text says 'he puts it in the dough.' This is a mistake. Even when they are next to each other, this is considered Mukaf. Even though the Chulin dough interrupts, this does not mandate putting the second dough in the first, for the Chulin dough is not a Hefsek. I found a corrected text that says 'he puts it near the dough.' Semag says like the Rambam, and he says that he puts in to the side of the first dough. We discuss when the Se'or was taken from a dough with a Shi'ur that obligates Chalah. If not, we would not need to find Parnasah from elsewhere. The case when there is no other Parnasah is when the dough (from which the Se'or came) was eaten or lost.

Radvaz: The Rambam says that he puts the second dough in the dough. If not, the Chulin dough would interrupt. We do not say that the Se'or is Batel to the dough, and he separates from Chayav (what is liable) on Patur (what is exempt), for any amount of Tevel forbids. It is not Batel. This is why the entire (first) dough reverted to be Tevel, and he separates on the entire dough. We do not say that Chalah and Chulin are mixed together. Everything that he separates is like Chalah in every way.

Rosh (Hilchos Chalah 9): If one took a Kav (note - it seems that he refers to Se'or, but the Terumas ha'Deshen (below) explains differently) from a dough that is Chayav, and put it in an exempt dough, if he has Parnasah from elsewhere, e.g. another dough that is Chayav, he separate one part in 24. This is not like separating from Chayav on Patur, since the Se'or is not Batel in the dough. A Tosefta says that he brings flour and kneads a dough to complete five Reva'im together with the Se'or. (A Rova (quarter-Kav) is the volume of six eggs. Five Reva'im obligate taking Chalah.) If he does not have a dough that is Chayav, and not flour, he separates one part in 24 on the entire dough. Any amount of Tevel forbids b'Mino, and the entire dough becomes Tevel to Chalah.

Rosh (Teshuvah 2:3): Some people use Se'or of Nochrim to ferment dough. When they separate Chalah, they take more than the amount of Nochri Se'or, lest they separate from Patur on Chayav. They need not do so. Rather, they knead a little flour, put that small dough on the big dough, and then separate that bit of flour they kneaded on the big dough. This is like Chalah 3:8. Parnasah is another dough from which he can do the needs of this dough and fix the Se'or of this dough. Do not say that this is not Chayav on Patur, for the Se'or is a small amount and it is Batel in the dough that is exempt, so then the entire dough is exempt. This is not so, for Se'or is added for taste, therefore, it is not Batel, and it is still Chayav. All the more so, when people use Se'or of Nochrim, the dough is Chayav, so it is not Batel in the dough that is exempt. Even though Se'or is for taste, the dough is primary with respect to the Se'or. They separate a second Chalah from the big dough.

Tosfos (76b DH v'Iy): How can one redeem the oil? It receives Kedushas ha'Guf (intrinsic Kedushah), for the Log (the Keli in which it is measured) is a Keli Shares (which is Mekadesh what one puts into it)! Perhaps a Keli Shares is Mekadesh what one puts into it only when it is full. Here, most of the oil was already Hukdash. It does not join with the addition that did not yet become Kodesh. Alternatively, it was put in the Keli Shares in order to receive Kedushas Damim.

Or Some'ach: The Yerushalmi says 'if not, he brings four Reva'im and touches, i.e. he touches the four Reva'im to the Tevel Se'or. Together there is a Shi'ur of Chalah. He separates from the four Reva'im according to the calculation. R. Yonah derived from here that if a Rova of Tevel Se'or makes another four Reva'im Tevel. I.e. one might have thought that one Rova from a dough that is already Tevel to Chalah cannot join with four Reva'im that were not yet Tevel to Chalah to complete the Shi'ur of five Reva'im and obligate Chalah. A Chiyuv cannot take effect on a Chiyuv. It is as if the Rova is away, by itself, and there is not a Shi'ur in the rest to be obligated. We say like this regarding Sava Lah (it is satiated with) Tum'ah (Tosfos Shabbos 91b DH Pachos). The Mishnah teaches unlike this. Even though the Rova already became Tevel, it joins to obligate the four Reva'im. Tosfos says (in one answer - PF) that the oil that is already Kodesh does not join with the addition that is not yet Kodesh.

Terumas ha'Deshen (190): After Pesach, people usually knead with Se'or of Nochrim (for no Yisrael has Se'or, and it takes a long time for fresh dough to become Se'or). There are many ways to fix it. The Rosh concludes that one may separate from the dough itself. We are not concerned lest he take the Nochri's dough and he separates from Patur on Chayav, for we hold that Yesh Bilah (we assume that things mix uniformly) for Lach (wet things, which totally mix. Also a dough is mixed.) Semak says that people do not rely on Bilah; this is a big stringency. However, the Mordechai and Or Zaru'a say not to separate in this way from the dough itself, for we hold that Yesh Bilah only for wine and oil. One must separate a larger amount than the Nochri's Se'or, for then the excess must be of the Yisrael. (Mid'Oraisa, there is no Shi'ur to Chalah.) Teshuvas ha'Rosh says that one should knead new dough, even though in his Pesakim he allowed to separate from the initial dough itself. It seems that he admits about Se'or that Ein Bilah, and in his Pesakim he does not discuss Se'or. However, Semak explicitly says that Yesh Bilah for Se'or. One should be stringent. How can we fix matters for the future? Women usually leave some of the dough to ferment future doughs. If they separate it before taking Chalah, it will remain Chayav. If they separate it after taking Chalah, it is exempt, like Se'or of Nochrim. (On Motza'ei Pesach,) even if one removes, before taking Chalah, the dough he will save to ferment future doughs, perhaps it is of the Nochri! It seems that we are not concerned lest this happen, and that also next time he will separate this same piece from the Nochri.

Shulchan Aruch (YD 324:11): If one took Se'or from a dough from which Chalah was not taken and put in dough from which Chalah was taken, and it is all the same species, if he has flour or dough from which Chalah was not taken, he separates from it on this dough according to the calculation, i.e. one part in 48 of the Se'or.

Rema: This is even if it does not have a Shi'ur Chalah, as long as he puts it next to the big Chalah.

Prishah (16, and Taz 10): My Rebbi (the Maharshal) says that this is only if Se'or was used, but a dough does not make Tevel unless it has a Shi'ur (to obligate taking Chalah).

Shach (18): The same applies if Tevel dough (not Se'or) was put into a Chulin dough. The taste of Tevel forbids any amount. Here it is easier to separate from the dough itself, for Yesh Bilah for wet things. What he separates will surely have some of the Tevel dough, and mid'Oraisa there is no Shi'ur. According to Terumas ha'Deshen, who says that Ein Bilah for Se'or, the Rosh permits separating from the dough itself only when the Se'or is Tevel and the dough is Chulin, for any amount of Tevel forbids, so the entire dough becomes Tevel. If Se'or of Nochrim (which is Patur) is put in Tevel dough, one may not separate from the dough itself, lest he take only the Patur Se'or. The Tur brings R. Peretz, who permits also in this case. This connotes that he holds that the Rosh agrees that Yesh Bilah even for Se'or. If so, the Rosh did not need to say that the entire dough became Tevel. Perhaps we rely on Bilah only when the dough is mostly Chayav, for then surely he takes some of the Chiyuv; mid'Oraisa, any amount suffices for Chalah. When only a little (the Se'or) is Chayav, we do not rely on Bilah, lest he take only from the primary dough. Therefore, we must explain that the entire dough became Tevel. I do not understand the Prishah, for in every case there is no Shi'ur mid'Oraisa for Chalah.

Nekudas ha'Kesef: Perhaps the Prishah means that it is Tovel only if it came from a big dough Chayav in Chalah. However, if so why did he mention Se'or? It is not different than dough. It depends only on the size of the dough it came from!

R. Akiva Eiger (DH d'Harei): Surely the primary dough is not Batel in the Se'or!

Gra (14): There must be five Reva'im in the new dough and the Se'or combined.

Aruch ha'Shulchan (42): The Yerushalmi says that Tevel mid'Oraisa is never Batel, but all agree that Tevel mid'Rabanan is Batel in the majority. Why do the Poskim say that even Tevel to Chalah of Chutz la'Aretz, which is mid'Rabanan, forbids any amount? Even in Eretz Yisrael, in the days of Ezra it was mid'Rabanan! Perhaps Chachamim were stringent like Torah law in Eretz Yisrael, in which the source is mid'Oraisa, but not in Chutz la'Aretz, for there there is no Torah source for Chalah.

Shulchan Aruch (ibid.): If not, he separates one part in 48 of the entire dough, since it becomes totally Tevel. The same applies if the Se'or is exempt and the dough is obligated.

Rema: L'Chatchilah one may not rely on this to put exempt Se'or in a Chayav dough. If he already did so, l'Chatchilah he may take from that dough and put in another dough to be for Se'or.

Gra (16): This is not l'Chatchilah, lest there be five Reva'im only with the Se'or, and he blesses l'Vatalah.

Beis Yosef (DH u'Mah): R. Peretz and Semag say that the same applies if the Se'or is exempt and the dough is Chayav. Orchos Chayim says that this is only b'Motza'ei Pesach, which is pressed circumstances.

Beis Yosef (DH Matzasi): If one did not take Chalah from a meat pie, can one separate (from dough)? The meat has only the taste (of dough). Is this like Chayav on Patur? Maharam learned from our Mishnah, of putting (Se'or) from a Chulin dough into a Tevel dough. This is not like Chayav on Patur, for Ta'am k'Ikar (if an Isur can be tasted in a mixture, the mixture is forbidden) is mid'Oraisa.