**1. Introduction**

Sustainable governance requires a shared set of values by which political elites affirm their allegiance to a set of ideals. They may differ in their interpretation of how they arrive at those ideals, but in successful states they ultimately cooperate for their political futures [1]. That shared set of values requires an understanding of their common past and of their collaborative potential and those understandings are forged in political discourse. In ancient Peru, and in many other societies, those shared interests were built in ritual acts consummated in special accords.

In the Wari empire (600–1000 CE), those agreements were formed, in part, during elite festivals, involving the consumption of *chicha de molle*, an alcoholic beverage of superb potency. Served in ceramic vessels that invoked the supernatural and or communicated elite allegiances [2,3], *chicha* consumed during ritual drinking sessions fomented political alliances and reified Wari ideology [4]. The most elaborately decorated ceramic cups may have established a link between vessels and solidified the relationships between the Wari elite who drank from them and the supernatural beings that controlled

water availability and fecundity that were presumably represented on these cups. The practice of drinking *chicha* invoked the flow of mountain water and represented the shared desire to exert supernatural control over the most precious resource—water [5].

These rites of incorporation relied on both specialized knowledge on how to produce them, as well as the material means to enact them at the various venues throughout the empire. Specialized knowledge involved the harvesting of clays to build the ceramic bodies and the acquisition of pigments to create the highly ritualized iconography painted on the vessels. It required the esoteric knowledge of the geometric designs and the graphic and vivid supernatural beings painted on the vessels and the means to execute them [6]. It also required a knowledge of the art of brewing and an understanding of the ethnobotanical materials that were the ingredients in a successful beer [7].

The material means to produce these events, in the Wari case, revolved around highly decorated and ritually charged iconography on ceramic brewing and serving wares [8]. Use of renewable local resources may have ensured that the various regional venues for these events were not dependent on resources beyond the regional governor's immediate control. That allowed for these festive events to be independent of disruption to trade routes, political bickering outside the local area, or interference from external adversaries. In other cases, ornate imported ceramic vessels might signal stronger affinity with the imperial center. However, their replenishment would be dependent on external producers distant from the brewing and feasting locales. Interference in the delivery of these goods could impact the ability to carry out the festivals that reaffirmed political ties and alliances.

The other important component for producing a Wari festival was the raw material for the brew itself. *Chicha* can be made of many different ingredients [9]. The most common base for *chicha* in the late prehispanic period was maize, and it remains to this day the most popular ingredient in the Andes. Other *chichas* from distinct areas of the Andes were reported by Spanish chroniclers to be made of tubers, peanuts, strawberries (*Fragaria chiloensis*) and other fruits, quinoa, and the berry of the Peruvian pepper tree, *Schinus molle*. This latter ingredient is especially interesting since finds of large quantities of desiccated *molle* seeds are often found in Wari sites, and provide a compelling indication of the type of *chicha* favored by the Wari [10]. We argue that both the ceramic vessels from which Wari beer was served, as well as the composition of the beer itself, were critical to making these events uniquely Wari. And it was only in these special circumstances that political allegiances sanctioned by Wari customs could be formed.

These accords were materialized both in the media from which the sacred beverage was consumed and in the liquid itself. The ceramic vessels in which the *chicha* was served were especially created for the elite event, and the brew which cemented the agreements conceived was also an extraordinary concoction focused on Wari culinary traditions rooted in local-imperial relations created for the occasion. Likewise, the events themselves were held in Wari architectural frames implanted within administrative centers throughout the imperial realm. These architectural complexes included features like platforms that highlighted the role of the patron of the feast in asymmetrical power relations with the attendees [11].

In this contribution, we utilize archaeometric methods to elucidate the technologies for producing and serving the political elixir for cementing relationships between elites in the Wari realm: *chicha*. In particular, we evaluate the special raw material sources used in the production of ritually decorated ceramics in which the brew was provided, as well as the essential constituents of the brew itself as preserved in the pores of the ceramics from which it was made and served.

#### *1.1. Cerro Baúl Brewery as Study Focus*

The materials on which this research is based were recovered from an ancient Wari brewery discovered at the site of Cerro Baúl [10,12]. Cerro Baúl was the southernmost administrative center in the Wari realm. Located in the Moquegua region of southern Peru, it occupied the summit of a unique mountaintop locale on the frontier with Wari's imperial rivals, the colonies of the Tiwanaku polity [13,14] (Figure 1). It was thus both a cosmopolitan political center and an embassy to a rival

polity. The nature of political interaction on this frontier was a critical example of Wari state practice, and at its heart was a large-scale brewing facility dedicated to producing a unique Wari brew served in highly decorated drinking vessels made on site [6]. Cerro Baúl provides evidence that Wari colonial governance in Moquegua was maintained in part through a ritual feasting center around *chicha* production. This pattern of governance persisted for four centuries on the southern Wari frontier, and implies the practice, as well as the governmental system it supported, were remarkably sustainable, including during periods of more arid climate.

**Figure 1.** Map of the Cerro Baúl site in the Moquegua research area.

Previous research has highlighted the contexts of the brewing traditions and the material remains of production debris [15–17] as well as the nature of Wari political economy [18]. Here we focus on archaeometric analysis of the materials used to create this event, arguing that it was the special contexts of production that made these alliances unique. We assess the nature of the material ingredients that formed the ceramic vessels and the potent brew they contained (Figure 2). This paper uses the results of ceramic sourcing studies and residue analysis of the ceramics from the *chicha* brewery at Cerro Baúl to understand how this practice sustained political interactions over the latter half of the first millennium CE.

**Figure 2.** *Cont*.

**Figure 2.** Example vessels from the Cerro Baúl brewery identified as part of the Baúl chemical group by INAA. They represent cups, fermentation and serving vats, and a *kero* or drinking mug.
