Ancient Peruvians partied hard, spiked their beer with hallucinogens to win friends

Lacing the beer served at their feasts with hallucinogens may have helped an ancient Peruvian people known as the Wari forge political alliances and expand their empire, according to a new paper published in the journal Antiquity. Recent excavations at a remote Wari outpost called Quilcapampa unearthed seeds from the vilca tree that can be used to produce a potent hallucinogenic drug. The authors think the Wari held one big final blowout before the site was abandoned.

“This is, to my knowledge, the first finding of vilca at a Wari site where we can get a glimpse of its use,” co-author Matthew Biwer, an archaeobotanist at Dickinson College, told Gizmodo. “Vilca seeds or residue has been found in burial tombs before, but we could only assume how it was used. These findings point to a more nuanced understanding of Wari feasting and politics and how vilca was implicated in these practices.”

The Wari empire lasted from around 500 CE to 1100 CE in the central highlands of Peru. There is some debate among scholars as to whether the network of roadways linking various provincial cities constituted a bona fide empire as opposed to a loose economic network. But the Wari's construction of complex, distinctive architecture and the 2013 discovery of an imperial royal tomb lend credence to the Wari's empire status. The culture began to decline around 800 CE, largely due to drought. Many central buildings were blocked up, suggesting people thought they might return if the rains did, and there is archaeological evidence of possible warfare and raiding in the empire's final days as the local infrastructure collapsed and supply chains failed.

Before that, however, the Wari enjoyed a period of relative peace and prosperity, with a capital city (just northeast of today's city of Ayacucho in Peru) that served as the center of the Wari civilization. The use of hallucinogens, particularly a substance derived from the seeds of the vilca tree, was common in the region during the so-called Middle Horizon period, when the Wari empire thrived.

Vilca typically grows in the dry tropical forests in the region. The trees produce long legumes filled with thin seeds. The seeds, bark, and other parts of the tree all contain DMT, a well-known psychedelic substance that is also found in the ayahuasca brews of Amazonian tribes. However, the primary active ingredient is bufotenine, the effects of which quickly wear off if the drug is taken orally. So it's usually smoked, ingested in the form of snuff, or used as an enema by those seeking the full hallucinogenic effect. A 4,000-year-old pipe laced with bufotenine residue and related paraphernalia was found in an Incan cave in Argentina in 1999—the oldest archaeological evidence to date for using vilca in South America.

There is also evidence from historical accounts that a juice or tea derived from vilca seeds was sometimes added to chicha, a fermented beverage made from maize or the fruits of the molle tree native to Peru. This is one way to take vilca orally while still getting a weaker, sustained psychedelic effect, since the beta-carbolines produced during the fermentation of chicha suppress the stomach enzymes that counter the high by deactivating the active compounds. "Collective consumption of vilca-infused beverages is also documented ethnographically, with the more sustained experiences recounted contrasting with the overwhelming hallucinogenic rush produced when consumed in other manners," the authors wrote.

For instance, people of the neighboring state of Tiwanaku were known to mix such hallucinogens with alcohol, specifically maize beer. There are monoliths depicting figures holding a drinking cup in one hand and a snuff tray in another, and smoking or inhaling vilca was part of a long-standing ritual tradition to foster personal spiritual journeys.

Biwer et al. think the Wari used vilca for a different purpose: to practice statecraft on a smaller, more intimately social scale. The culture was known for hosting elaborate feasts marked by the serving of alcoholic beverages. The remains of maize and molle are common at Wari archaeological sites, and pre-Hispanic serving vessels that were chemically analyzed showed traces of molle beer. Molle was likely the preferred crop for chicha because, unlike maize, it wasn't also grown for food, plus it is drought-tolerant. The drupes are also rich in hydrocarbons that serve as MAO inhibitors. "The hydrocarbons, when combined with the beta-carbolines produced by fermentation, would have heightened the psychotropic effects of vilca," the authors wrote.

There are depictions of vilca seed pods on Wari jars that are about the right size for serving chicha, but until now, there has been a lack of physical evidence supporting the hypothesis. Then archaeologists began excavating a remote Wari outpost called Quilcapampa between 2013 and 2017, likely home to just 100 Wari, even at its peak. They found the expected decorated drinking vessels, ceremonial clothing, stone tablets, and so forth, but no weapons indicating any kind of military presence.

That led the researchers to wonder whether the Wari might have opted for a different political strategy from conquering new regions by force. Perhaps they threw the elaborate feasts as a way of forging strong social ties with the inhabitants of the more remote regions in which they settled. They based this hypothesis on what they discovered in the soil around Quilcapampa. The excavation team collected 51 soil samples from various locations at Quilcapampa and then sifted the soil through a sieve to recover any plant material, which the arid conditions of the valley helped preserve.

The most abundant plant material they found was molle, which isn't surprising given its ubiquity in the region. Hundreds of thousands of molle drupes and stems were collected from all over the site. Fully 99 percent of the drupes didn't have resin and were deformed, strongly suggesting that they had been soaked or boiled to remove sugars—mostly likely to make molle chicha.

The team also recovered 16 vilca seeds, the first ever recovered from a Wari site. Unlike the molle drupes, the seeds were only found in a couple of Wari residential compounds, one of which also included the large pit where the bulk of the molle drupes were recovered. The authors believe molle chicha was likely brewed there. Since there was no snuff paraphernalia recovered from the site, it's most likely that the vilca was added to the chicha. This would be a new method of ingesting vilca, although chemical analysis of any residue still needs to be done to confirm the hypothesis.

“Instead of an abrupt, out-of-body experience, you would have a more elongated high [that] you would be able to enjoy with other people,” co-author Justin Jennings, a Royal Ontario Museum archaeologist who led the excavation, told Science. “[The Wari] take something that is an antisocial drug and make it a social one. I see these as boozy family dinners, building social relationships one [feast] at a time. The Wari are telling the locals, ‘Bring the molle, and we’re going to add the special sauce.’”

The trees don't grow naturally near Quilcapampa, so the vilca would have been imported to the Wari site, suggesting that it was a tightly controlled substance. Their guests would have lacked both access to the imported seeds and the knowledge of how to prepare the psychoactive brew.

"By tying their esoteric knowledge of obtaining and using vilca as an additive to molle chicha... Wari leaders were able to legitimatize and maintain their heightened status," the authors concluded. "These individuals were able to offer memorable, collective psychotropic feasts but ensured that they could not be independently replicated."

DOI: Antiquity, 2022. 10.15184/aqy.2021.177  (About DOIs).