By Porter Lang
You cannot make a dough from plain ground corn. Try it and the meal stays crumbly. Cook the whole kernels in limewater first, and the same corn turns into masa that holds together in the hand. The process has a Nahuatl name, nixtamalization, and it sits under the tortilla, the tamale and a good deal else. If you are shopping for a tortilla press, a grinding stone or a bag of masa harina, it helps to know what the step is for.
What the process is
Wikipedia defines nixtamalization as a process in which maize or another grain is “soaked and cooked in an alkaline solution, usually limewater,” then washed and hulled. UNESCO’s description of traditional Mexican cuisine, which we read, puts it more briefly: maize is hulled with lime, which increases its nutritional value.
The steps, as one food-science blog sets them out
Dave Arnold’s Cooking Issues, a personal food-science blog, gives a method for home cooks. Cook field corn in water with calcium hydroxide, known in Spanish as cal, for at least 30 minutes, and in his experience 40 to 60 minutes. Steep it. He says steeping time is not critical: a couple of hours is enough, and he suggests 8 to 10 hours or about 24. Drain off the liquid, called nejayote, rub the corn to loosen the skin and rinse twice. The result is nixtamal. Grind it into masa, with salt to taste. He gives ratios of lime at about 1 percent of the corn’s weight and water at two to three times its weight. We repeat this as one blogger’s method, not as safety advice, and we did not find a second source for the quantities.
Wikipedia describes the same shape of process without quantities: the kernels are cooked at or near boiling, steeped for a time that ranges from minutes to about a day, the liquid is discarded and the kernels are washed and the outer skin removed.
Why it makes dough
According to Cooking Issues, the alkaline water partly dissolves the pericarp, the outer skin, so the kernel absorbs water faster and grinds more easily. The dissolved skin becomes gummy compounds that give masa its cohesion, and gelatinized starch adds structure. Wikipedia puts the result in plain terms: untreated ground maize cannot form a dough by itself, but nixtamalized cornmeal can. That dough is masa, and dried and ground it becomes masa harina.
The word
Wikipedia says nixtamalization comes from the Nahuatl nixtamalli, combining nextli, meaning ash, and tamalli, meaning cooked corn dough. It adds that the Aztec and Maya used slaked lime, which is calcium hydroxide, and lye, which is potassium hydroxide.
Where it began
Wikipedia gives the earliest evidence as equipment on the southern coast of Guatemala dated to 1200 to 1500 BCE. Cooking Issues says the method was invented in ancient Mesoamerica more than 3,500 years ago, and that it spread to the American Southwest, where the result is called hominy and potash or lye is more common. Those two dates are close but not the same, and we leave them as stated.
What it does to nutrition, and where the sources disagree
Here we should be careful. Wikipedia says tryptophan becomes more available, which helps prevent niacin deficiency, and that calcium may rise by 750 percent, with 85 percent available for absorption. Cooking Issues says the process releases bound niacin, raises the corn’s calcium when calcium hydroxide is used and deactivates aflatoxins. But Wikipedia contradicts itself in two places. Its opening says mycotoxins such as aflatoxins are reduced “by up to 97–100%,” while its body says “by 90–94%.” And it says lime-treated maize “provided bioavailable niacin” to Mesoamericans while also calling the theory that niacin availability explains the anti-pellagra effect “disproven.” We report both and settle neither. Pellagra, the deficiency disease, is linked by Wikipedia to diets that rely on untreated maize, and the article says it was endemic in northern Italy in the late nineteenth century and in the southern United States in the early twentieth. This is not a medical page, and we give no health advice.
What UNESCO says
UNESCO added “Traditional Mexican cuisine, ancestral, ongoing community culture, the Michoacán paradigm” to its list of intangible cultural heritage in 2010. Its description calls the cuisine a comprehensive cultural model that includes farming, rituals, skills, cooking techniques and community customs. Corn, beans and chili form the base. The farming methods it names are milpas, rotating fields of corn and other crops, and chinampas, artificial farming islets in lake areas. It says corn is the basis of everyday tortillas and tamales, and that tamales are part of Day of the Dead offerings. It names grinding stones and stone mortars as characteristic utensils, and credits collectives of female cooks in Michoacán and across Mexico with keeping the knowledge alive.
Tortillas
Britannica describes a tortilla as a “round, thin, flat bread of Mexico” usually made from unleavened cornmeal, with wheat flour a less common base. Cooking Issues presses the dough in a cast-iron press lined with plastic wrap, then cooks it on a very hot surface of about 200 degrees Celsius or more for roughly 40 seconds per side, until it puffs. The blog does not mention a comal, the flat griddle that Mexican cooks use, and neither does Britannica, so we say nothing about it.
Dates in order
- 1200 to 1500 BCE: earliest evidence, southern Guatemala, according to Wikipedia.
- About 3,500 years ago: invention in Mesoamerica, according to Cooking Issues.
- 900 CE: the process has spread to the American Southeast, according to Wikipedia.
- 2010: UNESCO lists traditional Mexican cuisine.
Side by side
The three sources agree on the core: alkaline water, a soak, a wash, a grind. They disagree on the date of origin by a few hundred years, on how much aflatoxin is removed, and on how the niacin theory stands. UNESCO names the tools, Wikipedia names the chemistry, and the blog names the quantities.
What kind of sources these are
UNESCO’s intangible heritage page, which is the official description; Wikipedia, which anyone can edit; a personal food-science blog; and Britannica, which we read for one line. We read no cookbook, mill or tortilla maker and give no prices.
Questions a buyer would ask
Is the flour nixtamalized? Wikipedia says masa harina is dried, ground masa, which is nixtamalized cornmeal. Is the stone made for wet grinding? UNESCO names grinding stones as typical tools, and we say no more. Who made it? The sources do not say, and we name no maker.
What we left out
All prices. The Wikipedia remarks on corn chips and on how the process spread to the American Southeast. Any health claim beyond what the sources state. Any claim about a particular brand of masa harina, since we found none.
Quick answers
What is nixtamalization? According to Wikipedia, it is soaking and cooking maize in an alkaline solution, usually limewater, then washing and hulling it. The result is nixtamal.
Why do tortillas need lime-cooked corn? Wikipedia says untreated ground maize cannot form a dough by itself, but nixtamalized cornmeal can. That dough is masa.
Is Mexican cuisine a UNESCO heritage? Yes. UNESCO added traditional Mexican cuisine, the Michoacán paradigm, to its intangible heritage list in 2010.
Related on this site: xochimilco-canals-chinampas-trajineras, mariachi-instruments-history-unesco, cempasuchil-mexican-marigold-name-and-plant
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