BioEd Online

Shawl pins found on the floor of an excavated brewery have helped archaeologists to weave together a picture of ancient life in Peru. The pins belonged to elite women of the Wari Empire and support the idea that the site, which sits atop a 600-metre-high rock mesa called Cerro Baúl, served as a centre of diplomacy.

The 25-hectare summit of Cerro Baúl is known to have once been a bustling city, packed with houses and ceremonial buildings. Although archaeologists have known about these ruins since the 1970s, the exact purpose of the ceremonial areas has remained unclear.

The puzzle attracted the interest of Michael Moseley, an anthropologist at the University of Florida in Gainesville. Moseley has closely studied the Wari Empire, which ruled much of what is now modern-day Peru before being overtaken by the Incas around AD 1000.

Through careful excavation and analysis of the site, Moseley and his fellow researchers have pieced together a story of what they think happened there: the inhabitants were beer-makers, they say. And the workers involved were probably high-class women. The researchers say the booze was probably produced for drinking ceremonies with the neighbouring Tiwanaku people, with whom the Wari competed for scarce resources in the desert environment.

The Wari have been described as relatively secular and militaristic. The Cerro Baúl site represents a unique location where they had direct contact with members of the Tiwanaku state to the south.

Berries in the ashes

The team describe in Proceedings of the National Academy of Sciences¹ how the ceremonial area of Cerro Baúl is composed of a series of rooms where ash deposits suggest the presence of numerous fire pits. Berry seeds in the deposits, along with many fragments of ceramic vats and ceremonial cups, support the idea that the facility served as a brewery.

In the same region today, brewers of the traditional, beer-like 'chicha' drink boil spicy berries to create a syrupy mash that is later fermented.

The archaeologists tried their hand at recreating the ancient chicha recipe while visiting the region, though given the results Moseley says: "I'm not sure our ethnobotanist got the recipe right." The result was so spicy they had to mix it with modern beer to make it drinkable.

Moseley and his colleagues also found nearly a dozen shawl pins embedded in the brewery floor. These pins, which look like long needles with flattened heads, are thought to have belonged to the most privileged Wari women.

This hints that brewing was not a slave's task but part of a wealthy woman's sphere of activity. It also reinforces the idea that the elite class occupied Cerro Baúl and could have held drinking ceremonies with Tiwanaku representatives.

The archaeologists admit that the women could have thrown their pins on the floor as part of a ritual once the brewing was completed by someone else. But they point out that the pins are found throughout the ash deposits. Alternatively, the heat from the boiling vats could have made the women remove their shawls, they suggest, and the pins were lost in the process.