Recently I found myself in the grocery store facing a rather prosaic dilemma: What was the difference between cornmeal and masa, that corny foundation of tortillas and tamales? Was there a difference? They certainly looked the same on the shelves. Weren’t they both just ground-up corn? I wanted to make blue-corn enchiladas for my lovely—and had a vague notion of needing masa for that task—but the store carried only a white corn variety. Maseca, it was called. They did, however, stock numerous kinds of cornmeal: coarse-ground, fine-ground, blue, yellow, white, germed and de-germed. I stared longingly at the blue meal. It would make such pretty tortillas. I almost gambled and bought some, but a nagging thought stayed my hand: No, Peter, you need masa to make tortillas. That blue shit won’t work. Though this thought didn’t explain to me why exactly I needed the stuff, and why cornmeal wouldn’t suffice, I heeded it anyway. (A fortunate move, as it so happened, for my dinner plans later.) Turns out the story of masa isn’t as prosaic as I had assumed.
Masa is Spanish for “dough”. In the Americas the word is usually used in reference to masa de maíz, a corn dough made from freshly prepared hominy. (Hominy, by the way, is a chewy, puffed-up permutation of corn.) To fully understand masa, one must become familiar with something called nixtamalization, a procedure of which hominy is a direct result. Simply put, nixtamalization is a process whereby whole, dried corn kernels are cooked and soaked in a dilute alkaline solution—usually treated with wood ash or slaked lime (calcium hydroxide)—so that the pericarp, or hull, of the kernel sloughs off, and the endosperm swells with water. The alkalinity helps dissolve the glue-like hemicellulose of the kernel’s cell walls, softening the fibrous plant tissue, denaturing the proteins, and even converting some of the corn’s oils into emulsifying agents. After cooking and steeping (which may take hours or days, depending on the style of preparation), the poofy kernels—known as hominy at this point—are thoroughly washed and either ground fresh into masa de maíz, or dried and ground into shelf-stable masa de harina, which literally means “dough flour”. Technically, what I bought in the grocery store was masa de harina, which must be reconstituted with water and kneaded a bit before rolling. Because of the chemical changes effected by nixtamalization—including, among much else, protein denaturation and dissolution of hemicellulose—masa readily forms a dough that can be rolled and patted into tortillas, tamales, pupusas, arepas, and other delicious foods.The reason cornmeal won’t do this is because it’s not cooked, nor is it soaked in lime—two crucial steps that soften the kernels and better prepare the proteins within to recombine with one another, forming a pliable dough. Cornmeal is just dried, ground corn. This distinction wasn’t always apparent, of course—clearly not, because I had no idea up until this morning—and, curiously enough, some have paid dearly for the oversight.
The process of nixtamalization comes from the Aztecs, who coined the term by combining the Nahuatl word for “ashes”—nextli—with the nicely evocative tamalli, meaning “unformed corn dough”. It’s been practiced probably since the cultivation of maize in Mesoamerica, sometime around 1200 BCE. What the Aztecs undoubtedly realized was that nixtamalized corn was easier to grind, formed a tacky, versatile dough, and smelled and tasted better than untreated kernels. They probably also noticed that eating it, especially with beans, gave them strength and energy, whereas consuming the untreated corn alone conferred less of a benefit. What modern science has discovered is that nixtamalization actually makes corn more nutritious, at least for us humans. By soaking the kernels in lime, the niacin (also called vitamin B3) naturally present in corn becomes available for uptake, instead of just passing through the colon undigested. Niacin is a nutrient essential to humans, one of the forty to eighty so far identified. A deficiency in niacin—a condition still common in parts of Africa, Indonesia, and China, where malnourishment is rife—can lead to pellagra, a nasty disease characterized by diarrhea, dermatitis, dementia, and eventually death, if untreated. When maize was introduced to the Old World in the sixteenth century, it quickly became established as a primary food crop from southern Europe to much of Africa and eastward to Asia. What didn’t travel so swiftly, however, was the practice of nixtamalization. As a result, many who were relying increasingly on this miraculous grass for food weren’t getting the full suite of nutrients, and pellagra became a tragically widespread malady. It was first described in 1735 in Spain and soon plagued much of the Old World. It even reached epidemic proportions in the American South in the 1900’s. Eventually people noticed that areas of high corn consumption had commensurately high incidences of pellagra, and many believed that the kernel itself harbored some strange, nefarious toxin. It wasn’t until 1915 that an American scientist named Joseph Goldberger made the connection between corn-eating and pellagra, though it would be another twenty-two years before niacin was finally isolated as the missing link.
Anyway, back to my story. I bought the maseca, kneaded it with water, rolled the tortillas, made the enchiladas, and all was well. Secretly I was disappointed that they weren’t blue, but since that day I have found blue masa online and now, by golly, there’s no stopping me.