One is liable for Ha'alas Chutz (offering outside the Mikdash) a Kometz... or (Nisuch of) three Lugim of wine or water.

(Beraisa): Limbs and Eimurim of an Olah join to a k'Zayis to be liable for Ha'alas Chutz, and for Pigul, Nosar and Tamei.

Me'ilah 15b (Mishnah): Five things offered in (or with) an Olah join -- the meat, Chelev, flour, wine and oil.

Berachos 37a (Rav and Shmuel): One blesses Borei Minei Mezonos on anything containing the five grains.

(Rav and Shmuel): One blesses Borei Minei Mezonos on anything from the five grains.

It was not enough to teach the latter law, for one might have thought that this is only when it is totally made of grain, but not a mixture.

Chulin 120a (Mishnah): Rotev joins for Tum'as Ochlim.

(Rava): Rotev is fat.

Objection (Abaye): Fat itself has Tum'as Ochlim! Rather, it is congealed juice of the meat.

Question: Even if it did not congeal, it joins for the Shi'ur of Tum'ah!

(Reish Lakish): Brine on vegetables joins to the Shi'ur of a large date (to be liable for eating on Yom Kipur).

Answer: Liability for eating on Yom Kipur depends on what soothes someone fasting. For Tum'ah, it joins only if it is congealed.

Menachos 54a (Mishnah): If k'Beitzah of food, or a k'Zayis of Tum'as Mes was left in the sun and it shriveled to less than a Shi'ur, it loses its Tum'ah. If a k'Zayis of Chelev shriveled to less than a Shi'ur, one is not liable for it for eating Pigul, Nosar or Chelev;

If it was left in the rain and returned to its original size, it is again Tamei, or one is liable for eating it.

Rif (Berachos 26a): Anything that contains the five grains, we bless Borei Minei Mezonos beforehand, afterwards Al ha'Michyah. This is whether it has much grain or only a little.

Rambam (Hilchos Berachos 3:11): Anything on which we bless ha'Motzi beforehand, afterwards we bless Birkas ha'Mazon. Anything on which we bless Borei Minei Mezonos beforehand, afterwards we bless Al ha'Michyah, except for rice.

Rosh (Berachos 6:7): The Halachah follows the first teaching of Rav and Shmuel. Anything that it is primarily from the five grains, even if most is from other species we bless Borei Minei Mezonos beforehand, and afterwards Al ha'Michyah. This excludes if it has flour merely to make it stick together.

Tosfos (109a DH Olah): How can Chelev join with wine? The Shi'ur for Chelev is a Zikah, and the Shi'ur for wine is three Lugim! The Mishnah in Me'ilah means that they join for the Shi'ur to be liable for eating (but not for offering outside the Mikdash). The Shi'ur for consumption of liquids is a Revi'is only when one drinks them. If one soaked his bread in wine, the Shi'ur is a k'Zayis.

Shulchan Aruch (OC 210:1): One who eats less than a k'Zayis or drinks less than a Revi'is of wine or other drinks blesses beforehand, but not afterwards. Some are unsure whether we say a Berachah Acharonah on wine for a k'Zayis. Therefore, it is good to be careful to drink only less than a k'Zayis or (at least) a Revi'is.

Magen Avraham (1): A drink does not join with a food for a Berachah Acharonah. Brine on vegetables joins; anything for the sake of (solid) food is like food. The same applies to bread soaked in wine, like Tosfos says. It is not clear whether meat gravy is called a food.

Rebuttal (Igros Moshe OC 1:75): Tosfos does not mean that the liquid is considered a food. In Chulin we say that it is a food only if it congealed! Rather, it has the Shi'ur of a k'Zayis, like a food, even though it is a liquid. Since it has the same Shi'ur as a food, it joins with food. Rashi in Chulin holds that liquids for the sake of food do not join with the food.

Mishnah Berurah (1): Brine on vegetables; or wine absorbed in bread, joins for a Berachah Acharonah. However, if one ate bread with gravy without dipping it, it does not join. However, if the liquid had the same Berachah as the food, perhaps it joins. This requires investigation.

Kaf ha'Chayim (6): The Magen Avraham says that a liquid for the sake of a food joins with the food. The Chayei Adam disagrees.

Shulchan Aruch (208:9): If one mixed flour of millet or other legumes with flour of the five grains and cooked them in a pot, he blesses Borei Minei Mezonos and Al ha'Michyah. If he made bread from it, he blesses ha'Motzi and Birkas ha'Mazon. This is only if he eats a k'Zayis of the grain flour in Kdei Achilas Pras.

Mishnah Berurah (43): Pras is half a loaf used for an Eruv. Some say that it is three k'Beitzim, and some say that it is four. A k'Zayis is half a k'Beitzah. Therefore, one blesses Birkas ha'Mazon only if at least one eighth was from the five grains.

Kaf ha'Chayim (53): In Siman 612:4, the Shulchan Aruch says 'some say that Pras is four k'Beitzim... and some say that it is three.' In such cases, he always favors the latter opinion. Also in Siman 386:3 he brought only the latter opinion. Some say that since there is k'Zayis of grain in Kdei Achilas Pras, even if he did not eat a k'Zayis of grain, he blesses afterwards Birkas ha'Mazon. It is a Safek, so he blesses only Al ha'Michyah.

Gra (DH Kedei): There must be k'Zayis in Kdei Achilas Pras of the mixture, and he must eat k'Zayis in Kdei Achilas Pras of grain (in order to bless Birkas ha'Mazon afterwards).

Gra (DH bi'Tchilah): To bless ha'Motzi beforehand, we do not require k'Zayis in Kdei Achilas Pras. It suffices if it has from the five grains, as long as they are not (merely) to make it stick together. We learn from what Rav and Shmuel said about Borei Minei Mezonos.

Shulchan Aruch (ibid.): If he does not eat a k'Zayis of grain in Kdei Achilas Pras, he blesses ha'Motzi beforehand because there is the taste of grain. Afterwards he blesses Al ha'Michyah. If he cooked them in a pot, he blesses Borei Minei Mezonos and afterwards Borei Nefashos.

Source: Beis Yosef (DH v'Chasuv, citing R. Yonah).

Magen Avraham (15): The Avudraham says in the name of R. Yonah that a Mishnah in Chalah teaches that if a dough from wheat and rice has the taste of grain, one must separate Chalah and (if it was baked for Matzas Mitzvah,) one is Yotzei with it on Pesach. The Beis Yosef (453) says in the name of the Ra'avad and Rashba that it must have k'Zayis of grain in Kdei Achilas Pras. The Magid Mishneh and Ramban say that it need not have k'Zayis of grain in Kdei Achilas Pras. This is only for rice, but not for other species. The Rambam and Rosh agree. The Rambam (3:11) says that for anything that we bless ha'Motzi before eating it, we bless Birkas ha'Mazon afterwards. For anything that we bless Borei Minei Mezonos before eating it, we bless Al ha'Michyah afterwards, except for rice. The Yerushalmi says so. Why does the Shulchan Aruch say to bless (on the mixture) ha'Motzi beforehand, and Al ha'Michyah afterwards? We never find this in the Gemara! We must say that since for all Isurim, one is liable only if he ate k'Zayis in Kdei Achilas Pras, the same applies to Birkas ha'Mazon. However, if so why does he bless Al ha'Michyah? We can say that regarding Al ha'Michyah, one blesses for anything with the five grains, even if it is less than k'Zayis in Kdei Achilas Pras. However, if it was cooked, why does he bless Borei Nefashos?

Gra (DH uliv'Sof): The correct text of the Shulchan Aruch should say 'afterwards he blesses Borei Nefashos', like a cooked food without k'Zayis in Kdei Achilas Pras. Every Berachah Acharonah requires k'Zayis in Kdei Achilas Pras.

Mishnah Berurah (44,45): He blesses ha'Motzi beforehand even without k'Zayis in Kdei Achilas Pras because there is no Shi'ur for a Berachah Rishonah, and the grain is not Batel because one tastes it. If he does not taste it, it is Batel and he blesses sheha'Kol beforehand.

Mishnah Berurah (47): The Acharonim found the Shulchan Aruch very difficult. The Gra changed the text. One who fears Shamayim should eat such bread only inside a meal (of proper bread). However, we do not protest against one who follows the Shulchan Aruch. The same applies if the bread had k'Zayis of grain in Kdei Achilas Pras, but he ate less than a k'Zayis of grain in Kdei Achilas Pras. He says afterwards Al ha'Michyah according to the Shulchan Aruch, or Borei Nefashos according to the Gra.

Kaf ha'Chayim (54): When he did not eat a k'Zayis of grain, we descend one level. Therefore, after bread he says Al ha'Michyah, and after cake he says Borei Nefashos.

Kaf ha'Chayim (55): When there is not k'Zayis of grain in Kdei Achilas Pras, he washes beforehand without a Berachah, for some say that one must wash even for less than a k'Zayis of bread.

Mishnah Berurah (48): One can say Al ha'Michyah only if he ate k'Zayis of grain in Kdei Achilas Pras. This is not only when grain flour was mixed with other flour, and the grain is not so noticeable. It is also if he mixed grain flour with honey, spices or other ingredients, and there is not a k'Zayis of grain in Kdei Achilas Pras. This applies to potato Knishes or Burekas. However, the custom is to bless Al ha'Michyah on a k'Zayis of sweet cake, even if there is not a k'Zayis of grain. Perhaps because the spices are to improve the food, they join with the food to a Shi'ur, like the Magen Avraham said (210:1). L'Chatchilah one should ensure that there is a k'Zayis of flour.

Igros Moshe (OC 71): How can other ingredients join with the grain?! There is no support from the Magen Avraham, who learns from brine that joins with vegetables. There, it merely loses the status of a liquid, since it comes to fix food. We cannot prove that it is considered the same food (that it joins with), if we would need that particular food, like we do in order to bless Al ha'Michyah. The Magen Avraham discussed Borei Nefashos. However, we Menachos 54 proved this: If food or a k'Zayis or Tum'ah or Isur shriveled to less than a Shi'ur and due to rain it returned to its original size, it is again considered a Shi'ur. The water joins for a Shi'ur for Tum'ah or Chiyuv, even though we need flesh of a Mes or Isur. If it was initially less than a k'Zayis and it swelled to a k'Zayis, it is Tamei mid'Rabanan. If less than a k'Zayis of bread swelled to a k'Zayis, R. Akiva Eiger (Siman 210) brings from Gan ha'Melech that this is a Safek. Why is it a Safek? Just like water joins for Tum'ah mid'Rabanan, it joins with to obligate Birkas ha'Mazon mid'Rabanan (even though the Chiyuv even on a k'Zayis of pure bread is only mid'Rabanan if he was not satiated).