Corn is used as both a vegetable and a grain. For our purposes, in this chapter any dried corn product is considered a grain.
Corn may be dried on its own or processed with something alkaline, which makes it easier to remove the hull and germ. This second category — which gives the kernels that distinctive flavor you immediately associate with warm tortillas — has been around for thousands of years. The earliest American inhabitants discovered that soaking corn along with wood ashes (which contain lime — not the fruit but the chemical product) made the corn more digestible, and therefore more beneficial.
Here are the most common dried corn products and preparations.
Cornmeal is ground dried corn that hasn’t been treated with lime. It can be fine, medium, or coarse. You’ll find it both processed (usually under heat, so it winds up not tasting like much) and stone ground (the better choice), as well as made from yellow and from white corn. Corn flour is dried corn that has been ground into a fine powder; white and yellow versions are available. Be aware that in the UK “corn flour” refers to cornstarch.
This is masa, a dough made from ground hominy that is dried and ground; it has a texture somewhere between flour and fine cornmeal. Masa harina (also sold as masa de harina) is used to make tortillas, tamales, and other Mexican dishes. Most large supermarkets carry masa harina, and some also have the coarsely ground masa harina used for making tamales. Store masa harina for up to 6 months, preferably refrigerated.
Also sold as posole or pozole, this is whole dried corn kernels soaked in lime (calcium hydroxide, called cal in Mexico), with the hull and germ then removed. The kernels are big, and may be white, yellow, red, or blue. Dried kernels cook faster if you soak them for a few hours, as you would beans (though this step isn’t necessary). Cooked and canned hominy is also sold simply as “hominy.” Samp is cracked (not ground) hominy kernels. It is a popular ingredient in some African stews.