Why Passover is Different
When the Israelites were rescued by G-d from Egyptian slavery, they left in haste, leaving no time for the dough in their sacks to rise and become bread.
On Passover, we commemorate the rescue and the unleavened bread that the Israelites ate when they left Egypt. We don’t eat—or even retain in our possession—any “chametz”—leavened grain or its derivatives—from midday of the day before Passover until the conclusion of the holiday. Instead of chametz, we eat flat unleavened matzah bread.
What exactly is “Chametz”?
Chametz means any food or drink that contains even a trace of wheat, barley, rye, oats, spelt or their derivatives, and which wasn’t guarded from leavening or fermentation. This includes bread, cake, cookies, cereal, pasta and most alcoholic beverages. Moreover, almost any processed food or drink can be assumed to be chametz unless certified otherwise.
All products certified OK Kosher for Passover are marked OK P.