Central to the festival of Passover is hametz. But what, exactly, is hametz? The technical definition is clear: any of five grains that come into contact with water for more than eighteen minutes. But the technical definition merely tells us how grain becomes hametz. It does not tell us what hametz is. And suggesting that hametz is simply leavening – a substance that causes dough to rise – is not very helpful. Baking soda (sodium bicarbonate) causes dough to rise but is not hametz according to Jewish law. Hametz, it seems, is not just a chemical agent. So what is hametz?
At least four commentators would have us conclude that hametz is as much an idea as it is a substance. Rabbi Nahman of Bratzlav understands hametz to represent the evil inclination. Hence, his service for the Search for Hametz includes a prayer imploring God to allow us the benefit of purging the evil inclination from our souls just as we purge hametz from our homes. It is in this regard that the Midrash Tanhuma (Noah 15b) imagines God saying: “It was I who put the bad leaven in the dough, for the inclination of the heart is evil from his youth.”
The mystics consider hametz to be spiritual obstructions. Thus Rabbi Eliahu Klein writes (A Mystical Haggadah, p.10) that the “yeast in the bread” obscures the innate light that wishes to illuminate naturally. In other words, hametz is an energetic, psychological, and spiritual obstruction.
In his Holistic Haggadah, Michael Kagan, explains that hametz is tantamount to our over-inflated egos. Just as we need to rid our food of all things that puff it up, we need to rid ourselves of all false pride that puffs us up. And Ruth Gruber Freedman (The Passover Seder: Afikomen in Exile, p. 90) explains that matzah represents the spiritual ideal while hametz represents spiritual imperfection. That is why the Torah proscribes the use of hametz in the meal offering (cf. Leviticus 6:9-10) and in any sacrifice.
Perhaps the modern German scholar Benno Jacob (d. 1945) comes closest to identifying he real meaning of hametz by contrasting it with its opposite. Since matzah derives either from the Arabic cognate “mu-tza,” meaning “pure or clear,” or “ma-za,” meaning “tasteless,” hametz means “rich or opulent.” He thus concludes (Commentary on Exodus 12:13) that the ancient Israelite spirit considered all luxury and opulence as vulgar and barbaric. “Enjoyment led to vulgarity, while restraint [led] to nobility and priestly holiness.”
Thus hametz, as the centerpiece of the festival, lays emphasis on our task to become a priestly nation by living a life of restraint and nobility.