Uncorking the Past

by Patrick E. McGovern

  Many types of vessels that are known to have been used for chicha in Incan times have their counterparts in much earlier periods. The earliest pottery in South America, dating back to ca. 5000 B.P., seems to have been predominantly intended for fermented beverages. As yet, no chemical analyses of these vessels have been carried out, but this supposition is plausible given what we know about the difficulty of domesticating maize and the pivotal place of chicha in the mythology and social life of communities throughout the ancient Americas.

  Another tool of modern scientific archaeology—stable isotope analysis of ancient human bones—has helped determine whether corn chicha was being drunk by early Americans. The foods we eat leave telltale chemical signatures in our bones in the form of different isotopes of carbon, nitrogen, and other prevalent elements. Some very interesting results emerged when human bones from sites throughout the New World were examined. Because maize had been domesticated by about 6000 B.P., one would have expected to see a specific carbon-isotope composition that reflected the increased consumption of maize, but it was strangely missing.

  Some scientists have proposed an explanation for this anomaly. Because the analyses measured only the collagen in bone, its main proteinaceous connective tissue, they were biased toward detecting high-protein foods. Solid foods made from maize, including gruel or bread (e.g., tortillas), fit this requirement, but not fermented beverages like maize chicha, largely composed of sugar and water. Consequently, if people between 6000 and 3000 B.P. were consuming their maize as chicha, very little protein would have been incorporated into the collagen of their bones. The researchers speculated that humans began using maize as a solid food only after its ear had been substantially enlarged by selective breeding, around 3000 B.P. After this point, the carbon isotope compositions of bones dramatically changed.

  The isotopic results raise the American version of the Near Eastern query: Which came first, bread or beer, and which product spurred the domestication of barley in the Middle East and teosinte/maize in the New World?

  According to a recent proposal by John Smalley and Michael Blake, it was corn beer, or more precisely, a corn wine, that came first and provided the impetus for domesticating the plant. When a beverage is broadly dispersed, it is likely to be of deep antiquity. One of the most widely distributed fermented beverages in the Americas today is a wine fermented directly from the ultrasweet juice of pressed maize stalks. It does not go through a saccharification step, as is typical of beer. Smalley and Blake noted that modern cornstalk wine is made by pressing or chewing stalks of teosinte. Teosinte and maize both concentrate high levels of sugar in the stems of young plants. As the plants mature, the sugar moves to the kernels and is converted into starch. Collecting the stalks and ears early in their growing cycle guarantees a high-sugar resource (as much as 16 percent sugar by weight), ideal for making an alcoholic beverage. The same kind of reasoning lies behind the growing use of corn as a biofuel, which now accounts for most of the world’s production of alcohol.

  Conspicuous signs of prehistoric American interest in fermenting the sweet essence of maize show up in the form of chewed stalks, leaves, husks and ears left behind in caves of the Tehuacán Valley of Mexico, not far from the center of teosinte domestication in the Río Balsas. From about 7000 to 3500 B.P., the number of chewed maize quids declined. Over the same period, teosinte was being domesticated, and corn was coming into its own as both a liquid and a solid dietary staple.

  If teosinte and corn were exploited initially more for their sugar and wine potential, that could explain the gradual decrease in quids. This reasoning is consistent with the isotopic bone evidence implying that maize was first made and consumed as a beverage and the rapid dispersal of maize to other parts of the Americas only after it had been transformed into the larger-eared domesticate.

  As maize developed into some five thousand varieties of diverse colors, sizes, and degrees of sweetness, early Americans discovered more efficient ways to produce cornstalk wine. For example, the Tarahumara of Chihuahua in northern Mexico developed a process using ingenious nets woven of yucca fibers that replaced the chewing of the maize “cud.” By placing the cornstalks in the nets and twisting the nets between two poles, they could wring out nearly every drop of the nectar-like juice. The method is almost identical to the way ancient Egyptians carried out their final pressing of grapes.

  Other refinements followed. Perhaps as early as 3000 B.P., it was found that the tough hull surrounding each kernel could be removed by soaking and heating the milled corn in a dilute alkali solution, made from lime, wood ashes, or crushed shell. This procedure, called nixtamalization after the Aztec Nahuatl word for dough, also enhanced the amino-acid content and nutrient value of the corn.

  Ultimately, cornstalk wine slid in popularity when early Americans discovered that they could mass-produce a beer or chicha from the larger maize kernels and ears. By sprouting the maize kernels, they could activate enzymes, related to those in human saliva, that break down starches into sugar. The resulting sweet malt could be toasted, dried, and stored for future use, or diluted and fermented immediately into corn chicha.

  What the early Americans did not understand was how to start the fermentation. Unwittingly, insects probably transferred Saccharomyces cerevisiae to the sweet concoctions, whether cornstalk wine or chicha, and the yeast culture was perpetuated by using the same fermentation vessels repeatedly. Or possibly a tradition of mixing fruit and grain beverages accompanied human emigrants from Asia or became established in the Americas in the wake of experimentation with the new plants. Adding a high-sugar fruit, which has already been inoculated with yeast by insects, to a malt is a more assured way to initiate fermentation. A potent version of such a beverage from central Mexico, called the “bone breaker,” is recorded by the Spanish chroniclers: it combined cornstalk juice, toasted corn, and seeds of the Peruvian pepper tree (Schinus molle), another popular South American plant that could have provided yeast (see below).

  THE BIRTH OF CHOCOLATE

  The domestication of the cacao tree (Theobroma cacao) represents another signal achievement by early Americans. As with maize, the impetus for domesticating cacao was likely the production of a wine from its sweet fruit pulp. Cacao occurs naturally in the tropics, especially along the Pacific and Caribbean coasts of Central and South America and in Amazonia. It requires year-round water, temperatures that do not fall below 16°C (60°F), and dense understory debris to provide habitat for the midges that pollinate the cacao flowers.

  The fertilized flowers grow into football-sized pods that jut from the trunk and larger branches of the tree. Inside the pod is a juicy pulp surrounding thirty to forty almond-shaped seeds, known as beans. The beans, which contain concentrated bitter and aromatic alkaloids and other compounds, provide us with the wondrous “food of the gods” (the translation of the plant’s Latin genus name, Theobroma) that we know as chocolate. The same compounds, including the methylxanthines theobromine and caffeine, serotonin (a neurotransmitter—see chapter 9) and phenylethylamine (which has a structure closely related to dopamine and amphetamine, two other neurotransmitters), impart a similar chocolaty taste and aroma to the fruit. Ripe cacao fruits attract monkeys, birds, and other animals who are hungry for their abundant sugar (as much as 15 percent), fat (cacao butter), and protein. But animals eschew the intensely bitter beans and scatter them on the ground, where some take root as new trees.

  If a ripe pod strikes the ground and splits open, the pulp becomes liquid and begins to ferment. The Spanish chroniclers observed that native peoples along the Pacific coast of Guatemala delighted in a mildly alcoholic beverage derived from fermented cacao pulp, which they made by piling the fruit into their dugout canoes and letting it ferment there. “An abundant liquor of the smoothest taste, between sour and sweet, which is of the most refreshing coolness” (a long way from the sweet, hot cocoa to which we in the West are accustomed) accumulated at the bottom of the boat. A similar beverage is still enjoyed
in the Chontalpa region of Tabasco in Mexico and elsewhere in Central and South America where the tree grows wild or is cultivated.

  Fermentation of the pulp produces a liquid containing 5 to 7 percent alcohol. This is the first step in making modern chocolate: a mass of pulp is piled up at the cacao plantation, and after the pulp has fermented, it disintegrates and can be removed to collect the beans. As the pulp ferments and heats up, the beans start to germinate, until the internal temperatures rise to 50°C (122°F), which stops most biological processes. After five or six days’ fermenting, the beans’ astringency has given way to a more familiar chocolate flavor. The beans are laid out to dry in the sun for one to two weeks and then roasted for about an hour at temperatures approaching 120°C (240°F) to enhance aromas, colors, and tastes. Finally, the beans are shipped to chocolatiers round the world, who refine and blend them to create an array of culinary delights.

  Figure 19. Mesoamerican criollo cacao pod, full of almond-shaped seeds or “beans,” in a juicy, sugary pulp. The initial impetus to domesticate the plant probably came from converting the pulp into a fermented beverage, still made in Central and South America. Photograph courtesy of Dr. Nicholas M. Hellmuth, FLAAR Photo Archive. Photograph by Edgar E. Sacayón. Theobroma cacao, Arroyo Petexbatún, Sayaxché, El Petén, Guatemala.

  Before the early Americans learned how to make the chocolate beans into chocolate bars, sauces (moles), and beverages, they were captivated by the wine that came from the cacao fruit. Once again, biomolecular archaeology has provided the key data about this beverage. Fortuitously, in the fall of 2001, the lead story in the newsletter of my alma mater, Cornell University’s College of Arts and Sciences, was “The Birth of Chocolate” by the archaeologist John Henderson. He described how he and his colleague, Rosemary Joyce of the University of California at Berkeley, had excavated very early pottery vessels from the site of Puerto Escondido, on the Ulúa River in northern Honduras. He thought it likely that these vessels had once contained a chocolate beverage and concluded the article by stating what was really needed was chemical analysis of vessel residues to provide hard evidence for his hypothesis. It was as though a fellow Cornellian (John graduated a year after I did) was reaching out across the decades and asking for help. Although our paths had never crossed in Ithaca, I wrote to him to say that such an investigation was right up my team’s scientific alley and to propose a collaboration. Although we had previously devoted our efforts to unlocking the secrets of Old World fermented beverages, the same techniques could be applied in the New World. I soon heard back from John, who negotiated to bring some of the pottery back to the United States, and we were off and running on our scientific quest.

  The pottery samples from Puerto Escondido were some of the earliest yet found anywhere in Mesoamerica, dating back to around 1400 B.C. The site preceded the first urban communities of the Olmecs, centered on the Gulf Coast of what are now the Veracruz and Tabasco provinces of Mexico. Archaeologists had long surmised that the Olmecs, along with carving monumental stone heads and fashioning exquisite jade jewelry for their revered ancestors and gods, were the first to domesticate the cacao tree. This might explain why the best cacao in later Mayan and Aztec times came from the Chontalpa zone of western Tabasco, a dense, swampy area from which seafaring peoples carried their precious cargoes by canoe to Honduras. The ancient Mayan word for chocolate, kakawa or kakaw, derives from the Mixe-Zoquean family of languages, the same one to which Olmec belongs.

  Other regions of Mesoamerica well known for their cacao included the Aztecs’ prize area of Soconusco (Xoconochco) on the Pacific coast of southwest Mexico, the Ulúa Valley where John Henderson was working, and Izalco on the Pacific side of the narrow Isthmus of Tenuantepec. Some debate still exists among geneticists about where T. cacao was first taken into cultivation within its broad natural range. Truly wild plants are difficult to differentiate from feral descendants of cultivated plants, and sampling for wild and domesticated varieties in the historically important regions has been uneven. Yet all the archaeological and historical evidence points to Mesoamerica as the region where beverages and foods made from cacao were taken to their most sublime level. The particular cacao variety which is found there—criollo—also has an unsurpassed flavor and aroma profile, despite the more warty-looking appearance of the pod compared to the smoother and rounder forastero fruit of South America. It would be surprising if Mesoamerica, where so much effort was expended to make the best chocolate possible, was not also the area the tree was first domesticated.

  The Ulúa Valley would have been an excellent locale from which to disseminate this valuable product to other parts of Mesoamerica. The cacao tree thrives in the valley’s rich alluvial soil and tropical climate. Transport is facilitated by interconnecting waterways—mangrove lagoons, marshes, and lakes—which lead out to the river and the Caribbean. It is no wonder that when the Spanish invaded in the sixteenth century A.D., a king of Chetumal in the Yucatán, more than three hundred kilometers away, sent out a fleet of war canoes to defend the Ulúa Valley against the interlopers. The Spanish, of course, eventually won, but the fame of the valley’s cacao plantations spread to the Old World.

  To test whether the Ulúa Valley was indeed one of the earliest areas for cacao development in the New World, John chose jars and bowls from the earliest phases of the Puerto Escondido excavation, in which residences, defined by postholes, ranged from about 1400 to 200 B.C. During the first millennium B.C., the Maya civilization emerged in the lowland jungles of Guatemala and the Yucatán. Because these vessels had similarities to later spouted jars and drinking cups that the Maya reserved for their spiced, frothy chocolate drink, John surmised that the people of Puerto Escondido might have prepared a similar beverage for feasts and ceremonies.

  Either John had an eye for picking out chocolate vessels or Puerto Escondido was awash in cacao. Eleven of the thirteen pottery sherds tested positive for the fingerprint compound of cacao, theobromine. Theobromine occurs in other American plants, especially Ilex paraguariensis, a South American relative of holly whose leaves and twigs make the stimulating beverage maté or yerba-maté. This beverage is still consumed throughout South America, sometimes from a silver-accented gourd through a silver drinking tube. But among plants native to Mesoamerica, only cacao yields theobromine.

  In collaboration with the chemist Jeffrey Hurst of Hershey Foods, we demonstrated by gas and liquid chromatography, coupled to mass spectrometry, that theobromine was present in the eleven vessels and could only have been deposited there by a cacao product. Two of the jars tested were clearly intended for liquids (see figure 21). One that dated from the site’s earliest phase (the Ocotillo, from about 1400 to 1100 B.C.) had a tall neck and was strikingly shaped like a cacao pod, as if it were an ancient advertisement for its contents. The second jar dated to the most recent occupation (the Playa phase from 900 to 200 B.C.), and belonged to the wellknown “teapot” type. Jeff had already shown that the teapots of the Middle Preclassic period (ca. 600–400 B.C.) at the Mayan site of Colha in Belize contained a chocolate beverage. This type of vessel is widely dispersed from Middle Preclassic times until the Late Formative period (ca. 200 B.C.–A.D. 200) in the main areas of cacao production, from southern Mexico to El Salvador along the Pacific coast, and from Belize to Honduras along the Gulf of Mexico. It has also been found at many inland sites, including Veracruz, highland Chiapas, the Valley of Oaxaca, and central Mexico. The finest examples have been recovered from elite burials, such as those from a tomb at Monte Albán in Oaxaca in which nearly half the vessels were bridge-spouted teapots. Several were adorned with human “effigy” figures, with one wearing a macaw mask.

  Until Jeff’s analyses, it was pure speculation that the teapots might have once held a chocolate beverage. They are not illustrated on any of the later Maya frescoes and painted vessels. They appear to have first been associated with chocolate by the early twentieth century archaeologist Thomas Gann, who recovered several from a Mayan tomb at Sant
a Rita Corozal in Belize and noted their resemblance to the typical serving decanter for chocolate used in Europe since the sixteenth century.

  Curiously, the spouts of some of the early American teapots were attached near the base and curved backward, so that it would have been nearly impossible to pour a liquid from them. This odd spout placement is quite likely an important clue to their function. Later Mayan depictions of the cacao drink preparation show the beverage being poured at a substantial height from one cylindrical vessel into another in order to create a thick head of foam. Thousands of years later, the Spanish chroniclers describe how the Yucatán Indians, descendants of the Maya, made a “foaming drink [from cacao and maize] which is very savory, and with which they celebrate their feasts.” Conceivably, the awkward-looking teapots might have been used in an earlier period to create a foam by blowing air through the spout or stirring the beverage vigorously through the main opening. As the foam rose through the spout, one had the option to inhale the foam or drink directly from the mouth of the vessel.

  Figure 20. Painting from a Late Classic Mayan vase, showing a ruler about to partake of a foaming cacao beverage. Probable tamales covered with a cacao-mole sauce are heaped inside a serving bowl under the ruler’s platform. Photograph K6418 © Justin Kerr.

  The earliest chocolate aficionados during the Ocotillo phase at Puerto Escondido lacked such vessels to prepare their drink. They did have cacao-shaped serving jars and elegant high-fired and burnished cups, decorated with carved and molded designs of stars, diamonds, and human faces. Yet we have no evidence that they frothed this beverage, and our biomolecular archaeological results indicate that the primary attraction of this first cacao drink was its alcohol content.