Tishrei

Challah is the commandment to separate a portion from every batch of dough and give it to the priest. This mitzvah applies to dough made from the five species of grain - wheat, barley, spelt, oats, and rye - when it reaches a sufficient quantity. The Sages taught that challah is one of the mitzvot that apply even outside the Land of Israel, but its primary obligation is in the Land. After the destruction of the Temple, the Sages decreed that challah would be separated and burned, since it can no longer be given to the priest in purity. Through challah, even the bread in every home receives a dimension of holiness, and the table becomes like an altar.