The commandment to separate a small piece of dough [halla] is one of the mitzvot assigned to Jewish women, who are usually the ones responsible for the running of the kitchen at home. Originally, halla had to be given to a priest, as it is one of the “gifts of the priesthood” to which they are entitled for their devotion to the Temple service. The source of the commandment is the following passage from the Torah: “Speak to the children of Israel, and say to them: When you come to the land that I am bringing you there, it shall be, when you eat from the bread of the land, you shall set aside a gift for the Lord. The first of your kneading basket you shall set aside a loaf as a gift; like the gift from the threshing floor, so shall you set it aside. From the first of your kneading basket you shall give to the Lord a gift for your generations” (Numbers 15:18–21).

Like teruma, halla must be eaten by the priest in a state of ritual purity. Since the destruction of the Temple, it is impossible to attain ritual purity, and so today one is not required to give halla to the priests. Still, the command to separate halla applies nowadays as well. It is performed in commemoration of the original, full-fledged mitzva, in anticipation of the coming of the messiah and the rebuilding of the Temple. The separation also reminds one that everything he owns comes from God.

It is best to separate halla from the raw dough. According to Ashkenazic custom, one separates an olive-bulk (about 27 grams) of dough. If one failed to set aside the halla before baking, it should be separated afterward, with the stipulation that the separation is also for any substance that has been absorbed in the walls of the oven and the sides of the baking pan.

Not all situations are subject to the separation of halla; see below for details. Before separating halla from dough that is definitely subject to the requirement of halla, one recites a blessing:

“Blessed are You, Lord our God, King of the universe, who sanctified us through His commandments, and commanded us to separate halla (some add: from dough).”

One then burns the halla in fire, outdoors or on the stove, wrapped in silver foil. It is not necessary to burn it immediately; rather, one may accumulate several pieces of halla and burn them together. One who finds it difficult to burn the halla may wrap it in plastic and discard it in the garbage.

The obligation to separate halla applies only when one prepares a certain minimum amount of dough. There are differing opinions regarding this amount. On a practical level, one should set aside halla without a blessing if the dough contains at least 1.230 kg of flour. According to Rabbi Hayyim Na’eh (one of the most expert halakhic authorities of recent generations with regard to halakhic measurements), a blessing is recited over the separation of halla if there is at least 1.666 kg of flour in the dough. Some recite the blessing only if the dough contains no less than 2.250 kg of flour.

It is prohibited to split a large batch of dough into smaller pieces for the purpose of exempting oneself from the obligation to separate halla.