Types of Matzah
Traditional Jews refrain from using certain types of matzah at the seder.
Reprinted with permission from The Jewish Catalogue: A Do-It-Yourself Kit, edited by Richard Siegel, Michael Strassfeld, and Susan Strassfeld, published by the Jewish Publication Society.
Since the prescription regarding the eating of matzah in place of hametz is repeated several times in the Torah (see Exodus 12), it has come tobe observed with extreme strictness, particularly on the first two nights (seder nights). There are several types of matzah, varying in their strictness:
1. Shemurah (watched). Hand-made. The wheat is watched from the time of harvesting until the final baking to ensure that no water, heat, or othernatural processes cause it to begin fermentation. It is hand-made, constantly observed, and the utensils used for making it are washed every 18 minutes [and dried out] (the time when fermentation can begin, according to halakhah, Jewish law).
2. Shemurah (machine-baked). Same as above but baked by mechanical processes. Although this is kosher in all ways, some have questions as to whether the introduction of machinery necessitates revision in the laws.
3. Not shemurah. This is the supermarket matzah. It is only watched from the time of grinding (as opposed to the time of harvesting). Although this is also kosher, many people prefer to use the shemurah matzah to fulfill the mitzvah [commandment] during the seder, and use this for regular consumption during Pesach.
4. Egg matzah. Matzah baked with egg, milk, wine, or fruit extracts. It is called "unleavened bread prepared in a rich manner." Eating this will not fulfill the obligation of eating matzah at the Seder [and many traditional Jews refrain from eating egg matzah at all during Passover].