Heritage Field Notes · Category A
Nixtamalization — treating corn with an alkaline solution — is a 3,500-year-old technology that makes corn's B vitamins bioavailable, removes the hull, and transforms dried field corn into a nutritious staple. The USDA documented the ash and lime methods used in American households.
In 1942, the USDA Bureau of Human Nutrition and Home Economics published "Hominy and Hominy Grits," documenting the preparation methods used across the American South, Appalachia, and the Southwest for processing dried corn into hominy. The bulletin addressed two alkaline processing methods: wood ash lye (the older method) and food-grade lime (the method that was by 1942 displacing wood ash as lime became widely available).
Both methods produce the same result: the corn hull loosens and slips off, the kernel swells and softens, and the niacin (vitamin B3) bound in the corn's cellular structure becomes bioavailable to human digestion. This last point is the nutritional crux. Populations that ate corn as a dietary staple without nixtamalization developed pellagra — a severe niacin deficiency disease. Populations that nixtamalized their corn did not. The USDA documented this connection in multiple publications from the 1930s and 1940s.
The bulletin's practical purpose was preserving the household hominy tradition in communities that might lose the knowledge as processed hominy became commercially available. The food science behind the preservation rationale was straightforward: dried field corn could be stored indefinitely, processed into hominy as needed, and provided a nutritionally complete grain food that stored better and tasted better than the dried kernel alone.
Primary Source
Hominy and Hominy Grits
U.S. Department of Agriculture, Bureau of Human Nutrition and Home Economics. USDA Bulletin. Washington, D.C.: Government Printing Office, 1942.
Public domain — U.S. government work. Search the Internet Archive →
The Two Methods
The ash lye method (documented in the bulletin as the older traditional method): make a weak lye solution by leaching hardwood ash with water — the same process documented in the soap-making bulletin. Pour this solution over dried corn kernels, bring to a simmer, and cook until the hulls begin to slip. This typically takes 30-45 minutes.
Drain the lye solution, wash the corn thoroughly multiple times in fresh water, then rub the softened hulls off by hand or by working the corn against itself in water. The bulletin specified washing until the water runs clear — residual lye makes the finished hominy bitter.
The processed corn then requires further cooking (2-4 hours in fresh water) to fully soften the kernel. The bulletin noted that wood ash lye concentration was variable, making this method less consistent than lime processing, which is why lime had largely displaced it by 1942.
The lime method uses food-grade calcium hydroxide (cal, slaked lime, pickling lime) — a precisely consistent alkaline material available at Latin grocery stores and many supermarkets. The ratio: 1 tablespoon cal per quart of water, add 1 cup dried corn, bring to a simmer, cook 30-45 minutes. Cool overnight in the lime water.
Drain, wash thoroughly, remove any remaining hulls by rubbing. The washed, processed corn (masa) can be ground fresh for tortillas and tamales, cooked whole as hominy, or dried and ground as masa harina. This is exactly the same process used commercially for every tortilla chip and tamale sold in North America.
Safety: food-grade calcium hydroxide is safe at these concentrations. It is distinct from construction lime (calcium oxide, quicklime) which is caustic. Use only food-grade cal from the baking or canning aisle.
What It Teaches
The history of nixtamalization and pellagra is one of the clearest examples in food history of what happens when a food processing technique is abandoned without understanding why it worked. When corn spread from Mesoamerica to Europe in the 16th century, the nixtamalization process did not travel with it. European populations that adopted corn as a dietary staple developed pellagra at epidemic rates. The disease was eventually traced to niacin deficiency, and the niacin was eventually traced to the processing difference.
The USDA's 1942 bulletin was not written with this full epidemiological context — the pellagra connection was understood, but the mechanism (niacin bioavailability) was still being established. The bulletin's practical focus was on maintaining a food tradition that had clear nutritional value even if the complete science wasn't yet documented.
For modern households, the practical application is straightforward: dried field corn is inexpensive, stores indefinitely, and is transformed into an extremely nutritious and versatile food through a process that requires nothing but food-grade lime and time. Masa for tortillas, hominy for stew, grits from ground hominy — all of these begin with the same basic nixtamalization step. The knowledge to do it yourself converts an abundant, storable staple into a broad range of food options.
Sources