The main ingredients for making matzo are cold spring water and shemurah flour, which is flour kept free of moisture from the moment of harvest to the moment of packing. Matzo is an unleavened bread that Jews eat during Passover, made in a kosher kitchen in less than 18 minutes to not become a fermented grain, forbidden to eat during the holiday.
Baking matzo bread only requires two ingredients, but rules for preparation are strict to make it kosher for Passover. The entire work area, including the oven, must be thoroughly cleaned beforehand and all bakers involved with the preparation must have clean, dry hands.
The flour must be totally dry and stored in a cool, dark place. According to the strictest interpretation of the Talmud, the flour must be moisture-free from the time of reaping. More lenient interpretations say it has to be dry from the time of milling. During the kneading process, extra flour is not allowed to keep the dough from sticking to the work surface.
The water must be spring water, settled and cooled overnight in a perfectly clean vessel in a cool, dark place. Tap or bottled water is not allowed. The only water allowed in the work area is enough to mix the dough; bakers must clean surfaces with dry cloth or sandpaper only.