Complementing the prohibition of eating hametz on Pesah is the obligation to eat matzah. It is a positive commandment of the Torah to eat k'zayit, an olive's bulk, of matzah on the first night of Pesah. This practice is a reminder of the oppression which our ancestors suffered in Egypt and of the hasty Exodus. For the rest of Pesah, we are not specifically obligated to eat matzah, but, since we are forbidden to eat hametz, we are virtually forced by circumstances to do so.
Matzah is made of flour and water made into a dough kneaded thoroughly and then baked immediately at a high temperature so that it does not have a chance to rise. From the time that the flour and water and mixed, the entire process must be completed in no more than l8 minutes. Matzah may be made of any of the "five species" of grain (wheat, barley, rye, oats, and spelt), but the usual practice is to make it of wheat. In order to insure that no fermentation of the grain takes place, the process of making matzah must be very closely supervised by a knowledgeable person.
For most matzah, this supervision begins at the time that the grain is milled into flour. However, there are some who hold that the supervision must begin at the time that the grain is cut. Matzah made in this manner is called matzah shmurah ("watched" matzah). Some people eat only matzah shmurah all Pesah; many use matzah shmurah for the matzah shel mitzvah, the matzah which we are obligated to eat at the seder.
Egg matzah, known in Jewish literature as matzah ashirah (rich matzah), is made from Passover flour, eggs, sugar, and wine or cider. It is a confection, and not real unleavened bread; therefore, egg matzah may not be used at the seder. Since slight variations in the procedure for making of egg matzah would cause rapid fermentation, strict Ashkenazic practice is that only the very young, the elderly, and the ill eat egg matzah on Pesah.
