The Diversity of Zea Mays
Corn or maize (Zea mays) is perhaps the most important human food crop in the world, and probably one of the most controversal crops as well, owing to human manipulation of its genetics—by both traditional methods as well as modern genetic modification.
Corn has a controversial reputation due to how modern agriculture has genetically modified for mass production, bred to withstand the toxic conditions of conventional growing with pesticides, most often destined to be fed to livestock or used to make fuel. But corn is much more than animal feed or fuel. Corn is an important ingredient to the cuisine of our region in the SW USA, and of the Americas in general. Its towering nature makes it a fun crop to grow if you have the room.
Corn is much more than the modern monocrops that dominate agriculture.
There are many methods of growing corn, traditional and modern. Corn is best grown in full sun, and since corn needs lots of nutrients to grow, it is best grown in enriched soil. Most often in our region, it is grown as a “three sisters” crop. Sweet corn is planted in the spring (March-April) for the summer crop, and then in the monsoon season (July-August) for a fall crop. Other types can be planted throughout the warm season, but beware, corn does not tolerate high heat and low humidity during the period of tasseling. Therefore, timing is important: plant the spring crop before April 15 to ensure that the pollen released during the corn's tasseling period (30-70 days after planting depending upon variety) will occur before the dry early summer period to ensure fertilization. Alternatively, for the later crops, plant in mid-late July with the summer monsoon season and the corn will reach maturity when the temperatures drop a little and humidity rises.
Pay attention to descriptions when you purchase some corn varieties. Some varieties flower in response to a shortening of days and are best planted in the monsoon season, to be triggered by the shortening of days as fall equinox.
Three sisters planting with corn, beans, and squash
Corn is best direct-seeded. You rarely find them as transplants, as they don’t fair well as such. And corn is best planted in blocks rather than rows as it is a wind-pollinated plant. In our region, we often grow corn as a “three sisters” garden—corn does very well planted with bean crops that can vine up its vertical stalks, and squash plants that can shade the roots. The bean crops also encourage higher amounts of nitrogen in the soil due to their mycorrhizal relationships. For more on three sisters planting click here.
Corn can be an intimidating crop due to its diversity. What sort of corn should you grow and why? Below are the major groups of corn that you may encounter in seed catalogs: varieties for fresh eating, roasting, cornmeal, hominy, and some just for ornamental value or intellectual curiosity. Most edible types of corn also can produce huitlacoche, which is a fungus that grows on the ears of corn and is delicious. If you grow any amount of corn, you are likely to naturally get a few ears with this fungus. More on huitlacoche here.
Don’t be scared! It’s not science fiction, it’s huitlacoche!
The best places to get heirloom corn varieties
Native Seeds/SEARCH: By far the best place to get a large variety of heirloom corn varieties, especially of regional interest. This is by far our favorite source for corn seed.
Seed Savers Exchange: Best to join SSE to get the entire, full catalog. One of the sources for the ornamental japonica varieties of corn.
Baker Creek Heirloom Seeds: Not as exhaustive as Native Seeds/SEARCH, but they have some varieties of interest that occur worldwide.
Victory Seed Co: great alternative source for a large variety of corn.
Finally at the bottom of the article are some important terms concerning culinary methods regarding corn. This is by no means en exhaustive overview of corn and the associated cuisine. Massive books have been written on the subject, so just consider this a quick introduction and overview of corn.
Teosinte
(Zea mays ssp. parviglumis)
Teosinte is the common name for a group of four annual and perennial species of the genus Zea native to Mexico and Central America. Their general growth form is similar to that of maize, although they have much longer lateral branches. The name, teosinte, is of Nahuátl Indian origin, and it has been interpreted to mean “grain of the gods”. Some species of teosinte are distinct from maize both genetically and taxonomically, and they appear not to have played any role in the origin of maize. However, one form of teosinte, known as Z. mays ssp. parviglumis, shares a particularly close genetic relationship with maize and available evidence indicates that it is the direct ancestor of maize. This teosinte grows in the valleys of southwestern Mexico, commonly as a wild plant along streams and on hillsides, although it can also invade cultivated fields as a weed. It is most common in the Balsas River drainage of southwest Mexico and hence is also known as Balsas teosinte. This is the region that it is believed corn was domesticated about 9,000 years ago from these plants.
Today, it is mostly grown for intellectual curiosity, though the stalk is chewed in Mexico for its sweet juices.
Popcorn
(Zea mays var. everta)
Strawberry Popcorn
One of the the oldest form of domesticated corn—in modern times it is mostly used as popped corn (most people these days just call it popcorn). This variety of corn is also used nixtamalized (see description below) and used ground as coarse cornflour for grits, atole, or polenta, or it is used whole as hominy.
Flour corn
(Zea mays var. amylacea)
Hopi Blue Corn
Has a high starch content and is easily ground into flour. Some flour corn types can be harvested in what is called the milk stage (see below for description). Flour corn is normally nixtamalized (described below) and used to make ground corn flour, or used as whole, unground kernals for posole, chisos, or parched corn. Many landraces of flour corn are hybridized with flint corns (see below) or popcorn (see above) and their characteristics do not easily fit within these taxonomic categories.
Dent corn
(Zea mays var. indentata)
Hickory Cane Dent Corn
This is a type of field corn often used as livestock feed, in industrial products, or to make processed foods. Because each kernel has a hard starch on the outside, and a soft starch on the inside, when dried the soft part collapses creating the famous “dent” in each kernel. Most commercial corn grown in the world today is derived from yellow dent corn. The individual ears are hefty and large, supported by singular, strong stalks that tend to branch less than flour or flint types of corn. Used for cornmeal, elote (see below), hominy (and then into masa), or fermented into beer (Chicha, tesguino, Umqombothi) and perhaps further distilled into corn whisky.
Flint corn
(Zea mays var. indurata)
Otto File Flint Corn
Flint corn (similar to dent corn) is distinguished by a hard outer shell and kernals with a range of colors from white to red. Because flint corn has a very low water content, it is more resistant to freezing than other vegetables. It also helps them store well, and resist insect or rodent infestation. It is called flint corn because the kernels are notoriously hard “like flint”. Nixtamalized and made into a coarse cornmeal used for grits, polenta, and atole, as well as toasted and ground for pinole. Many landraces of flint corn are hybridized with flour corn (see above) or popcorn (also above) and their characteristics do not easily fit within these taxonomic categories.
Sweet corn
(Zea mays var. saccharata) & (Zea mays var. rugosa)
Country Gentleman sweet corn
This is the most familiar variety of corn to anglo people in the US (who aren’t farmers, anyway), Sweet corn is a hybridized variety of maize with a high sugar content—the result of a naturally occurring recessive mutation in the genes which control conversion of sugar to starch inside the endosperm of the corn kernel. This process is retarded in sweet corn, preserving the sugars that make it sweet.. Unlike field corn varieties, which are harvested when the kernels are dry and mature, sweet corn is picked when immature (milk stage) and prepared and eaten as a vegetable, rather than a grain. Since the process of maturation involves converting sugar to starch, sweet corn stores poorly and must be eaten fresh, canned, or frozen, before the kernels become tough and starchy.
Waxy corn
(Zea mays var. ceratina)
Waxy corn or glutinous corn is a type of field corn characterized by its sticky texture when cooked as a result of larger amounts of amylopectin. This corn has peculiar traits and was first described from a specimen from China in 1909. The starch content of the kernels is what separates waxy from regular yellow dent field corn. This is not a difference that can be seen by just looking at a corn field. Normal dent corn kernels consist of 75% amylopectin and 25% amylose while waxy varieties are nearly 100% amylopectin. After the wet milling process the resulting starch is used as a thickener and stabilizer in many food products. Waxy also makes good adhesives. Cardboard boxes may contain glue made from waxy corn. The sticky backing on envelopes is another adhesive product. The discovery in China of a distinct type of maize bears the historical question whether maize was known in the Orient before the European discovery of America. This isn’t a corn typically grown by the home grower, though it may be of interest for those wishing to create adhesive, or feeding livestock.
Occasionally but rarely some Asian heirlooms of waxy corn appear in the seed market.
Pod corn
(Zea mays var. tunicata)
Pod corn is not a wild ancestor of maize as once thought, but a mutant where each individual kernel is enclosed in long, membranous husks (known as glumes). This variant is interesting but only of ornamental or intellectual interest.
Striped maize
(Zea mays var. japonica)
Magnificent ornamental flint-type corn from Japan; known in the 1890s as Striped-Leafed Japanese Maize. Variegated leaves striped with green, white, yellow, and pink. Tassels are dark purple, kernels are burgundy. Use like flint corn, though normally just grown as an ornamental.
Some important corn cuisine terms
Milk Stage
About 18 to 20 days after silk emerges, the kernels are mostly yellow and contain "milky" white fluid. The milk stage of development is the infamous "roasting ear" stage—it can be picked and roasted to be eaten.Sweet corn is picked at this state. This is also the stage that, followed up with roasting, renders some of the less sweet corn types to be eaten like a sweet corn.
Nixtamalization
This process is commonly utilized in the production of tortillas and other related maize-based food products. The maize kernels are cooked with alkali, like lime or sometimes wood ash lye, and steeped in the cooking water with subsequent washing, at least twice, ensuring the removal of any remaining organic components and excess alkali. Nixtamal is the product obtained after this process, and it is subsequently ground to produce soft dough named masa. This is the base ingredient for the production of tortillas and other Mexican products. Remarkable physico-chemical changes occur in the maize during nixtamalization (resulting from heat treatment, lime addition and the steeping and grinding processes) which remarkably improve the nutritional quality of the maize. In particular, partial starch gelatinization, partial lipid saponification, solubilization of some proteins surrounding the starch granules and the conversion of the cell wall hemicellulose components into soluble gums all strongly influence the rheological and textural properties of the final products. Additionally this process is known to remove up to 97–100% of aflatoxins from mycotoxin-contaminated corn.
Chicos
Green or steamed corn that is dried is called chicos corn. It was at one time a common and widespread foodstuff but unfortunately it seems to have been mostly forgotten except in parts of the southwestern US and particularly in New Mexico.
Parched Corn
Roasted and dried whole corn kernels that are normally salted. They are eaten as a dry snack.
elote
A popular street food in Mexico, elote is a dish comprised of cooked sweet corn slathered in a spicy mixture of mayonnaise, crema, and chili powder and then sprinkled with cheese. There are many variations on elote.
atole
A thick, sweet, corn-based drink or gruel served hot.
polenta
A paste or dough made from coarse cornmeal, which is boiled and typically then fried or baked.
Chicha, Tesguino, & Umqombothi
Corn Beers
There are many methods of making corn beers. We encourage you to explore the many methods.
Hominy
Hominy is a food produced from dried maize kernels that have been treated with an alkali, in a process called nixtamalization. The corrosive nature of the solution removes the hull and germ of the corn and causes the grain itself to puff up to about twice its normal size.
masa
A corn dough that comes from ground nixtamalized corn. It is used for making corn tortillas, gorditas, tamales, pupusas, and many other Latin American dishes.