The Torah in Parashat Shelah (Bamidbar 15:20) commands that when a person bakes, he must take a portion from the dough and give it to a Kohen. This portion is referred to as “Halla.” The Sages understood that as this command was given to Beneh Yisrael in the wilderness, where the “bread” they ate was the daily portion of manna which descended from the heavens, this portion constitutes the minimum quantity of dough that is subject to the Halla obligation. In order to determine this minimum quantity, then, we must calculate the volume of the daily portion of manna. The Torah says (Shemot 16:36) that the daily portion of manna equaled one-tenth an Efa, which consists of three Se’a, and a Se’a consists of six Kabin. Each Kab contains four Lugim, and each Log contains six Besim (meaning, six times the volume of an egg). It turns out, then, that an Efa constitutes 432 Besim, such that one-tenth an Efa is 43.2 Besim. This, then, is the amount of dough from which one is obligated to separate Halla on the level of Torah obligation. This is alluded to in the word “Halla,” which in Gematria equals 43, and which ends with the letter “Heh,” alluding to the additional one-fifth of a Besa (as the numerical value of “Heh” is five). The Ben Ish Hai (Rav Yosef Haim of Baghdad, 1833-1909) calculated the volume of 43.2 Besim to be roughly 5 lbs., whereas Hacham Ovadia Yosef maintained that 43.2 Besim equals 3.5 lbs. The Sefer Ha’hinuch explains that the Torah gave us the Misva of Halla because bread is the primary staple on which people depend for their sustenance. G-d, in His infinite mercy, wanted us to accrue merit through which to earn material blessing, and so He gave us a command which can be observed on a frequent basis, each time we bake bread. Additionally, the Sefer Ha’hinuch writes, this Misva enables the Kohanim, who devote their time entirely to the service of G-d, to receive their sustenance easily, without having to disrupt their service. It emerges, then, that the Torah gave us the Misva both for our benefit, and for the benefit of the Kohanim. The Halla obligation takes effect only after one adds water to the flour and mixes it to form dough. It applies to flour made from any of the five principal grains – Hita (wheat), Se’ora (barley), Shifon (rye), Shibolet Shu’al (oats) and Kusemet (spelt). One who neglected to separate Halla from the dough may fulfill the Misva later, by separating a portion from the bread after it is baked. If one baked an amount of dough that is less than the minimum required amount for the obligation to apply, and then bakes more bread and places the loaves together in the same basket, they are regarded as a single entity with respect to Halla. This means that if the two loaves together amount to the minimum quantity that requires Halla, then one must separate Halla from this bread. This Halacha applies only if the two loaves are placed together in a basket with a Bet Kibul (receptacle). If, however, they are placed together on a flat surface, they are not seen as being combined into a single entity, and Halla does not need to be taken. The Torah obligation of Halla requires giving any amount of dough; even a small piece separated from the batter and given to a Kohen fulfills the Misva. However, the Sages enacted donating no less than 1/24 th of the dough to a Kohen. For a baker, who earns a living from selling his baked products, the Sages lowered the required percentage to 1/48 th . If a Jew co-owns dough with a gentile, then if the Jew’s portion consists of the minimum quantity that requires separating Halla, he must donate a portion of his share of the dough to a Kohen. Dough that was prepared for animal consumption does not require separating Halla. However, if dough is prepared for both human and animal consumption, then it requires Halla. This Misva is binding upon both males and females. The Biblical obligation of Halla applies only in the Land of Israel, when the majority of the nation lives there