Matzah, at the same time the simplest and most complex of kosher products, consists of just two basic ingredients: flour and water. On Passover we avoid all wheat-based products save one: matzah. 
So how is the same wheat kernel so dreaded as the forbidden chametz, then transformed into matzah, the iconic representation of the Passover holiday and eaten at the Seder in fulfillment of a Biblical obligation?
The Basic Ingredients
For most of the year, flour mixed with water is considered a kosher-friendly combination. But special production requirements come into play when blending the two for Passover. The merging of these ingredients to make Passover matzah necessitates a meticulously monitored environment, one that prevents the product from becoming chametz, which is defined by our rabbis as fermented grain.
Levels of Shmurah Flour
All wheat flour used in matzah production must be continually supervised. While kosher supervision of Passover flour used in “regular” matzah begins prior to its milling, the flour used in “shmurah” (watched) matzah is supervised from the time that the wheat is harvested in the field. Wheat can only be used to make matzah flour if it has been inspected against any signs of moisture. The flour mill, bins, and transport vessels must be koshered for Passover; and any equipment used for chametz-milling that cannot be adequately cleaned must be effectively sequestered.
Mayim Shelanu
Water to be used in matzah baking must be left to stand overnight (to ensure that it is allowed to cool). This water is then referred to as “mayim shelanu” (water that has “slept”).
As mayim shelanu is necessary for the preparation of each day’s production, the mashgichim supervising a matzah bakery must take care that:
- the water tanks are filled immediately prior to nightfall;
- there is sufficient mayim shelanu for the next day’s matzah production;
- no additional water is added to the mayim shelanu tank during the day’s production.
Safeguarding Against Insect Infestation
The potential for insect infestation must be addressed when dealing with any grain product.
Matzah bakeries protect against infestation by:
- enforcing a quick turnaround of flour that will allow the least amount of time between grinding and baking;
- regularly cleaning flour bins and receptacles;
- sufficiently cooling all flour silos and production areas;
- employing a rigid sifting protocol of the flour prior
to baking.
Flour-Dust Control
The flour and water that make matzah must be mixed and kneaded into dough in a rabbinically supervised, controlled environment. Any flour dust generated by the mixing process must be contained to ensure that it does not drift into other areas of production, thereby contaminating the dough being rolled into matzah. It is therefore essential that the flour be restricted to a mixing-process station. As an additional safeguard, the mixing (flour and water) and rolling (dough) should best take place in two completely separate areas.
Heat and Fermentation
The heat generated by the oven, and the machinery running in an industrial matzah bakery, can create enormously high temperatures. This excessive heat, a primary factor connected with fermentation, must be avoided in a matzah bakery; consequently, special precautions should be instituted to maintain temperatures around the oven door (pi hatanur).
18-Minute Matzah/Cleanup of the Matzah Bakery
All matzah bakeries, whether producing hand or machine matzot, ensure that less than 18 minutes elapse from the time the water touches flour to the time the matzah enters the oven. (There are those who set the 18-minute standard to include the baking time as well).
After each 18-minute run, all stationary equipment must be completely cleaned or swapped out for clean ones. Accordingly, used bowls, rolling pins, and dockers that would have residual flour or dough are scrubbed or switched and tables and prep surfaces are cleaned before the clock on a new batch of dough begins to count down.
The halachic principle of eisek* (continual manipulation) allows for matzah-baking machinery that is in constant motion (rollers, cutters, conveyors, etc.) to continually produce matzah for Pesach without being stopped and cleaned every 18 minutes.
However, if the equipment is stopped without it being completely cleaned, the residual material will be rendered chametz and could adversely impact the Pesach status of the matzah.
Machine made matzot labeled as “18 Minute Matzot” specify that the entire dough processing line is shut down and cleaned prior to processing these matzot – not relying on the principle of eisek.
Unacceptable Matzot
In order for matzah to be properly and thoroughly baked, sustained levels of heat are required for a prescribed period of time; if the matzah is not thoroughly baked, it is considered chametz. Mashgichim must therefore continuously monitor ovens against any drop in baking temperatures.
Two other types of inadequately baked matzot are:
kefulot — matzot with folds;
nefuchot — if the scoring is insufficient, the matzah will swell (like a pita), indicating that the center of the matzah has not been adequately baked.
Articulated Intent
Jewish thought attributes to Passover not only the freedom from physical servitude, but also our people’s emancipation of spirit. So the performance of our mitzvot must not only be fulfilled with diligence and precision, but with the full engagement of our hearts and minds.
In addition to the multitude of material requirements in making matzah, there is a critical obligation that every batch of matzah prepared is preceded by the baker’s declaration, “le-shem matzat mitzvah,” that it is being baked to provide matzah for all who would taste freedom in the fulfillment of the Divine command.
