Directions
In its earliest Native American form, culinary lime (aka culinary lye and potash) was a mixture of water and wood ash in which corn was cooked to remove the clear outer coating of each corn kernel. (That cellophane-like coating is called pericarp, incidentally, and you’ll recognize it as the clear stuff that gets stuck between your teeth when you eat popcorn). Simply put, wood ash and water mixed together form potassium hydroxide, a naturally caustic chemical that makes hard proteins in the corn pericarp soluble—it literally eats the pericarp away. Today, more often than not, taking the place of the water-and-wood-ash brew is culinary lime, a white powder purified from natural calcium deposits, that is stirred into water to make lime water.

Dried corn simmered in lime water is called hominy (a North American colonial frontier term) or posole or nixtamal (both Central or Native American words); the last also names the cooking process. Native Americans favored nixtamal preparation because it allowed—and still allows—dried corn to cook quickly and promoted, in their view, its digestibility and nutrition. Modern nutritional assessment of the nixtamal process confirms Native American instincts: Nixtamal makes niacin and other micronutrients in corn accessible in ways that simmering dried corn in plain water does not. Nixtamal corn is America’s first nutraceutical, and it tastes damn good.

In the American South, hominy preparation during the Great Depression came to be known as “bucket lye hominy” for the farm bucket used to prepare it: Wood-fire ash was collected in a bucket, the bucket filled with rainwater, and the mixture steeped like tea. Today, a handful of talented and dedicated restaurant chefs employ similar old-time techniques, taking ash leftover from hardwood grill fires to make lime water, which they then use to make hominy and masa. The rest of us, though, use culinary lime, whose demand is preserved by stalwart home canning cooks—e.g., by Southern cooks who traditionally use it to crisp and keep their pickles green. Some supermarkets still carry culinary lime—at Walmart, for instance, it is available under its Latin American name, cal. If you prefer to have culinary lime appear on your doorstep, Anson Mills offers it as well.