Cornchip Day

What the day is

Corn Chip Day is observed on January 29. Behind a bowl of chips sits one of the most consequential food processes ever developed.

Origin and background

Corn chips are made from masa, and masa is made by nixtamalization: soaking and cooking dried corn in an alkaline solution, traditionally water with wood ash or slaked lime, then rinsing and grinding it. Mesoamerican cultures developed this thousands of years ago, and it does several things at once. It loosens the tough outer hull, changes the starches so the dough holds together, and produces the particular aroma that distinguishes a real tortilla from anything made with plain cornmeal.

The critical effect is nutritional. Corn contains niacin in a bound form the human gut cannot absorb, and the alkaline treatment releases it. Where corn was adopted as a staple without the process, which happened as it spread from the Americas into Europe, Africa and the American South, populations developed pellagra, a niacin deficiency disease causing dermatitis, diarrhea, dementia and death. It killed large numbers of people over centuries, and the technique that prevents it had been in use the whole time in the regions corn came from. The cause was only identified in the twentieth century.

The commercial corn chip descends directly from this. It is masa, pressed and fried, and the difference between a chip made from nixtamalized corn and one made from plain corn flour is immediately obvious in both smell and flavor.

The fried chip is also a case where the oil temperature decides everything, as with fritters: too cool and the dough absorbs oil instead of sealing.

How to take part

• Check the ingredients for masa or nixtamalized corn rather than corn flour.
• Warm them briefly in an oven, which revives stale chips completely.
• Make fresh tortillas from masa harina once, which takes minutes and tastes nothing like packaged.
• Read about pellagra, which is a striking case of losing a technique along with a crop.
• Salt them while still hot from the fryer if you make your own, so it sticks.