Maize Was Primarily A Liquor Ingredient For More Than Four Thousand Years After Its Domestication

Maize was domesticated in the Americas around the same time as the independent Neolithic revolutions in the Fertile Crescent (ca. 8000 BCE), in both North and South China respectively (ca. 6000 BCE for Millet farming in the Yellow River Basin in the north, and around the same time for rice cultivation in the Yangtze River Basin in southern China) and in the highlands of Papua New Guinea (also around the same time).[1] 

But, this didn't lead to a full fledged Neolithic revolution with attendant civilizational and technological advances in the Americas until roughly four thousand years later (i.e. in the time period from 2700 BCE to 2000 BCE, predating the Classical Mayan period by more than a thousand years), according to a new study. 

Until then, Maize was a crop used predominantly to make alcoholic drinks, a bit like modern niche crops like agave and hops today, by people who were basically hunter-gatherers.

"Farming allowed us to live in larger groups, in the same location, and to develop permanent villages around food production. These changes ultimately led in the Maya area to the development of the Classic Period city states of the Maya between 3,000 and 1,000 years ago. However, until this study, we did not know when early Mesoamericans first became farmers, or how quickly they accepted the new cultigen maize as a stable of their diet. Certainly, they were very successful in their previous foraging, hunting, and horticultural pursuits before farming, so it is of considerable interest to understand the timing and underlying processes," he said. 

Radiocarbon dating of the skeletal samples shows the transition from pre-maize hunter-gatherer diets, where people consumed wild plants and animals, to the introduction and increasing reliance on the corn. Maize made up less than 30 percent of people's diets in the area by 4,700 years ago, rising to 70 percent 700 years later. 

Maize was domesticated from teosinte, a wild grass growing in the lower reaches of the Balsas River Valley of Central Mexico, around 9,000 years ago. There is evidence maize was first cultivated in the Maya lowlands around 6,500 years ago, at about the same time that it appears along the Pacific coast of Mexico. But there is no evidence that maize was a staple grain at that time. 

The first use of corn may have been for an early form of liquor.

From Science Daily.

The paper and its abstract are as follows:

Maize is a cultigen of global economic importance, but when it first became a staple grain in the Americas, was unknown and contested. 

Here, we report direct isotopic dietary evidence from 52 radiocarbon-dated human skeletons from two remarkably well-preserved rock-shelter contexts in the Maya Mountains of Belize spanning the past 10,000 years. 

Individuals dating before ~4700 calendar years before present (cal B.P.) show no clear evidence for the consumption of maize. Evidence for substantial maize consumption (~30% of total diet) appears in some individuals between 4700 and 4000 cal B.P. Isotopic evidence after 4000 cal B.P. indicates that maize became a persistently used staple grain comparable in dietary significance to later maize agriculturalists in the region (>70% of total diet). These data provide the earliest definitive evidence for maize as a staple grain in the Americas.

Douglas J. Kennett et al., "Early isotopic evidence for maize as a staple grain in the Americas." 6(23) Science Advances eaba3245 (June 3, 2020) (open access).

[1] Some other background and context regarding the history of agriculture follows.

Other independent Neolithic Revolutions. There were three other independent Neolithic revolutions that each occurred several thousand years after the four main independent Neolithic revolution events in the Fertile Crescent, North China, South China and Papua New Guinea. And, while the Papuan Neolithic's first crops were domestically early (just as they were in Meso-America), the full Papuan Neolithic package may not have been sufficiently assembled to allow a conversion to a food producing lifestyle until 3000 BCE to 2000 BCE.

There was an independent Neolithic Revolution in Ethiopia and across the Sahel to West Africa. 

There was a second independent Neolithic Revolution in the eastern United States which was superseded by the Meso-American agricultural package in late pre-Columbian times. 

And, there was a third independent Neolithic Revolution in the Amazon River Basin in South America which petered out without spreading widely or being replaced by the Meso-American package for reasons that are currently unknown, but were probably related to climate changes.

Assembling Neolithic Domesticate Packages. Further, each of the independent Neolithic revolutions didn't take hold until several domesticates sufficient to constitute working "package" of domesticated plants and animals sufficient to make it possible to transition from a hunter-gather means of subsistence to a herding and/or farming means of subsistence was assembled.

In the Fertile Crescent case, different components of the package of domesticates that made a Neolithic package viable with domesticated, respectively, in Mesopotamia and the Zargos Mountains, in the Anatolian highlands, and in the Levant.

In Meso-America, the "three sisters" (corn, beans and squash) were domesticated in different places at different time.

The Neolithic revolutions didn't occur anywhere in the world prior to this time for reasons related to climate change.

Derived Neolithic Revolutions. Elsewhere in the world, agriculture was largely derived from one or more of these independent Neolithic revolutions in Pre-Columbian times.

In Europe, North Africa, Iran, the Indus River Valley, and Central Asia the primary source was the Fertile Crescent Neolithic package. 

The Meso-American Neolithic package (once fully assembled and used for staple subsistence) spread to both North America and South America.

Elsewhere in East Asia and in Southeast Asia, Oceania and Northeast India, the primary source was the Chinese Neolithic package, which in many cases happened after the North Chinese Neolithic package and the South Chinese Neolithic package had integrated.

The Sahel African Neolithic package was exports to South India where it was integrated to some extent with select components of the Fertile Crescent Neolithic package.

The Neolithic packages of the highlands of Papua New Guinea, of the Eastern United States, and of the Amazon were never widely exported.

Local Neolithic Package Enhancements Places that received a particular based independent Neolithic package often added some secondary domesticated animals and crops that were domesticated locally at a later date, and often shared with other places that had agriculture based upon the same package of domesticates.

For example, guinea pigs, yams and the llama were added to the Meso-American Neolithic package in the highlands of Pacific coastal South America. Cotton and the donkey were added to the Fertile Crescent Neolithic package in Egypt. One kind of camel was added to the Fertile Crescent Neolithic package in North Africa and the Middle East, and another kind of camel was added in North Asia along the Silk Road. Horses were added to the Fertile Crescent Neolithic package in the Pontic-Caspian steppe. Some secondary grains and vegetables and cows were added to the Fertile Crescent Neolithic package in the Southeast Europe. Bananas were added to the Chinese Neolithic package in Indonesia. The indica strain of rice was added to the Fertile Crescent Neolithic package in northern India.

Likewise, some of the original crops in these Neolithic packages, like the "ancient grains" of the original Fertile Crescent Neolithic package have subsequently been abandoned or superseded.

Modern Global Agricultural Integration By the "age of exploration" starting in the late 15th century CE, regular, bidirectional maritime trade at global distances had started the process of integrating particular domesticated plants and animals from other packages into the local agricultural package. 

This has happened only sporadically before then (e.g. the merger of the North and South Chinese Neolithic packages facilitated by the development of a non-tropical strain of East Asian rice and the importation of Indian strain rice, the arrival of the yam from South America to Oceania, and the transmission of Indonesian domesticates from Borneo to Africa by Austronesian mariners).

Some of the most notable age of exploration exports to the wider world to grow domestically New World crops including spicy peppers which were rapidly adopted globally in warmer climates, the potato, the yam, and corn, the spread of wheat and cotton to North America, and the spread of coffee to Indonesia and South America. 

Other domesticated crops, like tea from Southeast Asia and tobacco from the Americas, soon became widely exported, but did not result in much cultivation outside the areas where they were already established.